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Partial tear down of Willsenton R8


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Posted (edited)
13 hours ago, xlr8or said:

Here you go:

 

Screenshot_20210506-070559_FTBC Lite.jpg

 

Adjust the bias to 35 mA.

 

Thanks Kirk, but I am still confused. The app asks me to input the Plate Current, which you have shown as 35mA - where do you get this figure from - it isn't in the data sheet I posted. Also, you say to adjust the bias to 35mA, but what does that 61.6% 'Bias' figure indicate - that is the figure the app calculates after I input the following:

 

Max Plate Dissipation - 25W (I can get that from the data sheet OK)

Plate Voltage - 440V (I got this figure from you in this thread, specific to the R8 AIUI).

Plate Current - I can't see this info in the datasheet but am required to put it in.

 

Once I have entered those three items of info, I then press calculate and the app computes:

 

Bias - 61.6%

Plate Dissipation - 15.4W

 

What am I missing?

 

EDIT: As I was replying to Ian, it occurred to me that the Plate Current figure may be specific to the amp, not the tube (hence it not being in the datasheet). If so, where does the 35mA figure to set the bias come from?

 

 

Edited by Zed Zed
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18 hours ago, muon* said:

What does the app ask for?

 

You have to input Max Plate Dissipation, Plate Voltage and Plate Current. The amp then calculates Bias as a percentage figure (percentage of what??) and Plate Dissipation in Watts.

 

 

 

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Posted (edited)

Just set to 35ma, the plate voltage is 440v and it uses 10 ohm cathode resistors, so yeah, 35ma sounds right.

 

Edit: for an EL34

I don't use that app' so can't advise on it, but obviously Kirk knows it well.

Edited by muon*
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Posted (edited)
6 minutes ago, muon* said:

Just set to 35ma, the plate voltage is 440v and it uses 10 ohm cathode resistors, so yeah, 35ma sounds right.

 

I am not getting something here. If, for the R8, I always set Plate Voltage to 440v and Plate current to 35mA, what is the app calculating? It calculates two data once the three user-filled data are input, one of which is 'Bias' expressed as a percentage (in the case of the 6CA7 it is 61.6% and the other is 'Plate dissipation' expressed as Watts (15.4W in this case).  I can't see how the app calculates the mA setting I need to be able to use my fancy new meter (when it gets off the slow boat from China). Sorry to be so thick on this, but it is all new to me.

 

I can, of course, just use the 35mA figure for the meter as you and Kirk have said, but in that case, I can't understand what the purpose of the app is.

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Posted (edited)

It's to confuse you :lol:

 

Seriously, under Bias in that app it is showing percentage, not the setting you need, that is expressed in the plate current bit, so if you set them at 35ma you get 61.6% or whatever and that is in the green zone so is good!

 

At least that is how I'm seeing it.

Edited by muon*
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3 minutes ago, muon* said:

It's to confuse you :lol:

 

Haha. Then it is working exactly as intended! :) 

 

3 minutes ago, muon* said:

 

Seriously, under Bias in that app it is showing percentage, not the setting you need, that is expressed in the plate current bit, so if you set them at 35ma you get 61.6% or whatever and that is in the green zone so is good!

 

At least that is how I'm seeing it.

 

But I have to put in the Plate current data myself! I thought the purpose of the app was to tell me what mA setting I needed for a specific tube/amp. If the purpose of the app is to tell me that the tube I am using is OK within the parameters of the amp (green zone) that's fine, but what I was trying to establish is the figure I am trying to achieve with the fancy new bias meter when I adjust the bias pots. Kirk rightly pointed out that a meter will be better than the dial on the R8 which just tells me to centre the needle, but gives me no idea of the actual bias current. Using the new meter I can twist the bias pot to get an exact readout in mA - but of course this requires me to know what that readout should be. So far, the only way I can get that bit of crucial data is from you and Kirk ;) But I suspect that there is another way, for those poor buggers who do not have the advantage I have of knowing you guys (it's not what you know, it's who you know etc ;) )

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Posted (edited)
2 minutes ago, Zed Zed said:

 

Haha. Then it is working exactly as intended! :) 

 

 

But I have to put in the Plate current data myself! I thought the purpose of the app was to tell me what mA setting I needed for a specific tube/amp. If the purpose of the app is to tell me that the tube I am using is OK within the parameters of the amp (green zone) that's fine, but what I was trying to establish is the figure I am trying to achieve with the fancy new bias meter when I adjust the bias pots. Kirk rightly pointed out that a meter will be better than the dial on the R8 which just tells me to centre the needle, but gives me no idea of the actual bias current. Using the new meter I can twist the bias pot to get an exact readout in mA - but of course this requires me to know what that readout should be. So far, the only way I can get that bit of crucial data is from you and Kirk ;) But I suspect that there is another way, for those poor buggers who do not have the advantage I have of knowing you guys (it's not what you know, it's who you know etc ;) )

35ma is good as the app indicates with It's % in the green zone.

Edited by muon*
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Posted (edited)
3 minutes ago, muon* said:

35ma is good as the app indicates with It's % in the green zone.

 

Ah - the light is glowing dimly in my brain . . . So the bias current can be a range!  IOW, if I decide to run the tubes a bit hotter, so long as the result stays in the green zone, I am OK? If I want to run them a bit cooler, that is also OK?  If I am right, is there an 'idea' setting for bias - eg is it 'ideal' to run so that the green zone figure is 50%, or 60% or whatever?

 

IOW, if I input a bias percentage of 35%, the app tells me I need to set the meter to 19.9mA.  A bias percentage of 60% requires a meter reading of 34.1mA and so on. Have I finally understood?? ;) 💡💡💡

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1 minute ago, Zed Zed said:

 

Ah - the light is glowing dimly in my brain . . . So the bias current can be a range!  IOW, if I decide to run the tubes a bit hotter, so long as the result stays in the green zone, I am OK? If I want to run them a bit cooler, that is also OK?  If I am right, is there an 'idea' setting for bias - eg is it 'ideal' to run so that the green zone figure is 50%, or 60% or whatever?

I guess smack in the middle of the green zone, whatever that is.

 

But trust me that with 10ohm cathode resistors and that plate voltage 35ma is the common setting used.

 

If running them colder you will get a more relaxed sound but maybe too relaxed (system dependent) and running them hotter they live a shorter time and might be prone to instability quicker if there is an issue.

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As long as the selected plate current runs the tube in the green zone it's fine. The 440v is fixed and cannot change. It's an inherent feature of the R8 and represents the B+ going to the power tubes. I would advise using 35mA as it's only at 61.6% of total power dissipation of the tube and at the lower end of the green zone.

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1 hour ago, muon* said:

I guess smack in the middle of the green zone, whatever that is.

 

But trust me that with 10ohm cathode resistors and that plate voltage 35ma is the common setting used.

 

If running them colder you will get a more relaxed sound but maybe too relaxed (system dependent) and running them hotter they live a shorter time and might be prone to instability quicker if there is an issue.

 

1 minute ago, xlr8or said:

As long as the selected plate current runs the tube in the green zone it's fine. The 440v is fixed and cannot change. It's an inherent feature of the R8 and represents the B+ going to the power tubes. I would advise using 35mA as it's only at 61.6% of total power dissipation of the tube and at the lower end of the green zone.

 

Thanks guys. I (finally) understand it now.  35mA it is. Meter has been ordered.  👍👍👍

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Just AAMOI, the bias on all four (KT88) tubes is totally stable again today, so I think I can rule out a problem with the R8 itself. Fingers still crossed. And I still intend to get those resistors fitted.

 

Although the sound of the KT88s isn't for me, I am impressed at how much more grunt the amp has when using them - a big reduction on the volume control for my usual listening levels. But it#s still EL34s for me I think - I am not lacking power with my speakers/room/music/listening level preferences.

 

I also like the way the KT88s look - very 'purposeful'. But the amp is for listening, not looking :) 

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I am fortunate to have a very good guitar shop not too far away from where I live, and since guitar amps are invariably tube amps, the shop also sells a wide variety of tubes. They are exclusively current production, however. So today, I have acquired a matched quad of four Tung Sol EL34B tubes, which, by all accounts, are not too bad for current production tubes. I just couldn't listen to the KT88s really, and I did try, but they are not for me. Or at least, the stock Willsenton KT88s are not, and I have never heard any others.  I went this route as an alternative to replacing the one faulty EH 6CA7 Fat Boy, or buying a fresh quad of those. Now that I have the four EL34Bs, I will probably just get a single EH 6CA7 replacement. My intention ultimately is to get a matched quad of NOS EL34s and I suspect that the new TS EL34Bs will do for me for now. Also, I am wary about spending serious wedge on four NOS tubes until I have had those resistors fitted.

 

The new TS EL34Bs are installed, biased to the centre of the meter, and have approximately 30 minutes of burn-in on them ;)  But you know what -- I can tell immediately how much more they are to my taste and how much more I am enjoying them than the KT88s. Immediately.  I will recheck the bias in a couple of hours and adjust if needed, and then keep an eagle eye on them for a few days just to be on the safe side.

 

Thanks, yet again, for the help I have received from this amazing thread. I would be totally lost without you guys! 

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Posted (edited)

OK - what may be useful info . . .  I took a close look at the suspect EH 6CA7 tube. It has a bad case of dandruff on the inside!  At first I thought the little marks were on the outside of the glass, but they are on the inside, and they move around if I shake the tube. A bit like a really cr&p snowglobe. I checked the other tubes and none of them have any traces of this.

 

So, any ideas as to a) what the white residue is and b) what can cause it? Clearly something is amiss with this one tube.

 

I have marked in red one or two of the examples, for clarity, but you can see plenty all over the tube.

 

2021-05-06_15-48-02.png.447c11f310f657224da7a66b4c2fb2e0.png

 

2021-05-06_15-47-32.png.cf2132f0dbcd67646f7b98e26d42aad9.png

 

Edit: I was just showing / boring Mrs Zed with this and notice the dandruff had moved about quite a bit and seems to be breaking up into smaller particles as I handle the tube. See this photo:

 

2021-05-06_15-58-25.png.cb27461aedf69f2e799027bf26671627.png

 

 

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5 hours ago, Zed Zed said:

I am fortunate to have a very good guitar shop not too far away from where I live, and since guitar amps are invariably tube amps, the shop also sells a wide variety of tubes. They are exclusively current production, however. So today, I have acquired a matched quad of four Tung Sol EL34B tubes, which, by all accounts, are not too bad for current production tubes. I just couldn't listen to the KT88s really, and I did try, but they are not for me. Or at least, the stock Willsenton KT88s are not, and I have never heard any others.  I went this route as an alternative to replacing the one faulty EH 6CA7 Fat Boy, or buying a fresh quad of those. Now that I have the four EL34Bs, I will probably just get a single EH 6CA7 replacement. My intention ultimately is to get a matched quad of NOS EL34s and I suspect that the new TS EL34Bs will do for me for now. Also, I am wary about spending serious wedge on four NOS tubes until I have had those resistors fitted.

 

The new TS EL34Bs are installed, biased to the centre of the meter, and have approximately 30 minutes of burn-in on them ;)  But you know what -- I can tell immediately how much more they are to my taste and how much more I am enjoying them than the KT88s. Immediately.  I will recheck the bias in a couple of hours and adjust if needed, and then keep an eagle eye on them for a few days just to be on the safe side.

 

Thanks, yet again, for the help I have received from this amazing thread. I would be totally lost without you guys! 

 

The TS EL34Bs are still my number one out of many power tubes I've rolled in the R8. I wanted to push you to get them a while ago, but you were enjoying your EH. Now the question I have been wondering: How do they compare/differ from the EH 6CA7? The 34Bs are my "one to beat" which I can compare everything else, and the EH 6CA7 is one of the few power tubes I have not yet tried, so curious to hear your thoughts.

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20 minutes ago, echorec said:

the EH 6CA7 is one of the few power tubes I have not yet tried

When you say this are you talking about current production only?

 

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36 minutes ago, echorec said:

 

The TS EL34Bs are still my number one out of many power tubes I've rolled in the R8. I wanted to push you to get them a while ago, but you were enjoying your EH. Now the question I have been wondering: How do they compare/differ from the EH 6CA7? The 34Bs are my "one to beat" which I can compare everything else, and the EH 6CA7 is one of the few power tubes I have not yet tried, so curious to hear your thoughts.

 

I am glad you asked! Now it is early days and my TS EL34Bs have only a few hours on them, so please bear that in mind. HST, WOW!  Just WOW! I am blown away. They have the edge on my EH 6CA7 Fat Boys. The midrange is even more lovely and so smooth and euphonic and musical. The top is clear without a hint of strain or stridency. Human voice is a little more forward, but not too much, and has an even greater sense of realism. And the bass is, to my taste, terrific. It is deep enough and has a fabulous 'organic' and 'fruity' quality, which I like. It may tend a little to plumpness but personally I like bass that way as it is more reflective of the kind of bass I hear in real life. I dislike the 'dry', 'fast' bass that seems to be the modern trend. But remember my musical tastes of course!! For those who rejoice to Led Zep etc, then maybe these EL34Bs would not be what they want.

 

Personally, I would not recommend that you try the EH 6CA7 Fat Boys (unless you really want to just to scratch the itch). Not because they are not great tubes, because I think they are, but simply because they are not massively different to the TS's. Like I say above - the latter 'have the edge' and they do, to my ears (and in the context of my tastes and other gear), beat then in all the parameters which are important to me. Knowing that you and I seem to share our tastes very closely, I suspect your view of the EH 6CA7 Fat Boys would be similar to mine. A great tube, but less great than the TS EL34B.

 

As you may have read, I have been using the Willsenton KT88s for a couple of days, but they are everything that is opposite to what I have said above. In the end I couldn't take the sound any more and had to drive out to a local guitar shop earlier today and buy myself a perfectly matched pair of the Tung Sols. I am sure I will eventually try some NOS EL34s. If they beat these Tung Sols, I will have died and gone directly to heaven :)

 

BTW, I am 'all Tung Sol' for the moment. I have the four EL34s, three of their current production 6SN7s and two NOS 6C8G 'Black Bottoms' in the 6SL7 positions. The latter will change when those ShuGuang Black Treasures eventually find their way off the boat. Can't be long now. I will burn in the EL34Bs for 70 or 80 hours before I install the ShuGuangs.

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48 minutes ago, muon* said:

When you say this are you talking about current production only?

 

 

Yes, new production. Would love to get some vintage 6CA7s at some point, but my gear priorities have changed and I have so many tubes that my wife is starting to become suspicious. 😅

 

20 minutes ago, Zed Zed said:

 

I am glad you asked! Now it is early days and my TS EL34Bs have only a few hours on them, so please bear that in mind. HST, WOW!  Just WOW! I am blown away. They have the edge on my EH 6CA7 Fat Boys. The midrange is even more lovely and so smooth and euphonic and musical. The top is clear without a hint of strain or stridency. Human voice is a little more forward, but not too much, and has an even greater sense of realism. And the bass is, to my taste, terrific. It is deep enough and has a fabulous 'organic' and 'fruity' quality, which I like. It may tend a little to plumpness but personally I like bass that way as it is more reflective of the kind of bass I hear in real life. I dislike the 'dry', 'fast' bass that seems to be the modern trend. But remember my musical tastes of course!! For those who rejoice to Led Zep etc, then maybe these EL34Bs would not be what they want.

 

Personally, I would not recommend that you try the EH 6CA7 Fat Boys (unless you really want to just to scratch the itch). Not because they are not great tubes, because I think they are, but simply because they are not massively different to the TS's. Like I say above - the latter 'have the edge' and they do, to my ears (and in the context of my tastes and other gear), beat then in all the parameters which are important to me. Knowing that you and I seem to share our tastes very closely, I suspect your view of the EH 6CA7 Fat Boys would be similar to mine. A great tube, but less great than the TS EL34B.

 

This is perfect, thank you! Your description of the TS EL34B sound in the R8 matches my general opinion. For sure, they have the best midrange out of the 7 quads I've rolled (all new production except the RFTs). Their midrange is the most liquid and three dimensional. Some changes I experienced in my 34Bs after I first bought them: The soundstage opened up after a week or two. They have the most natural and largest soundstage out of all my power tube rolling. The top end became clearer and the midrange also "bloomed" over that first two weeks. Yes, they get better. Enjoy!

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1 hour ago, echorec said:

 

Some changes I experienced in my 34Bs after I first bought them: The soundstage opened up after a week or two. They have the most natural and largest soundstage out of all my power tube rolling. The top end became clearer and the midrange also "bloomed" over that first two weeks. Yes, they get better. Enjoy!

 

I have already noticed that huge soundstage!  I am very excited to hear how these develop when they have 80 or more hours on them. :) 

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9 hours ago, Zed Zed said:

OK - what may be useful info . . .  I took a close look at the suspect EH 6CA7 tube. It has a bad case of dandruff on the inside!  At first I thought the little marks were on the outside of the glass, but they are on the inside, and they move around if I shake the tube. A bit like a really cr&p snowglobe. I checked the other tubes and none of them have any traces of this.

 

So, any ideas as to a) what the white residue is and b) what can cause it? Clearly something is amiss with this one tube.

 

I have marked in red one or two of the examples, for clarity, but you can see plenty all over the tube.

 

2021-05-06_15-48-02.png.447c11f310f657224da7a66b4c2fb2e0.png

 

2021-05-06_15-47-32.png.cf2132f0dbcd67646f7b98e26d42aad9.png

 

Edit: I was just showing / boring Mrs Zed with this and notice the dandruff had moved about quite a bit and seems to be breaking up into smaller particles as I handle the tube. See this photo:

 

2021-05-06_15-58-25.png.cb27461aedf69f2e799027bf26671627.png

 

 

Why is there a silvery coating inside a vacuum tube? (adventures-in-audio.com)

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11 hours ago, Zed Zed said:

OK - what may be useful info . . .  I took a close look at the suspect EH 6CA7 tube. It has a bad case of dandruff on the inside!  At first I thought the little marks were on the outside of the glass, but they are on the inside, and they move around if I shake the tube. A bit like a really cr&p snowglobe. I checked the other tubes and none of them have any traces of this.

 

So, any ideas as to a) what the white residue is and b) what can cause it? Clearly something is amiss with this one tube.

 

I have marked in red one or two of the examples, for clarity, but you can see plenty all over the tube.

 

2021-05-06_15-48-02.png.447c11f310f657224da7a66b4c2fb2e0.png

 

2021-05-06_15-47-32.png.cf2132f0dbcd67646f7b98e26d42aad9.png

 

Edit: I was just showing / boring Mrs Zed with this and notice the dandruff had moved about quite a bit and seems to be breaking up into smaller particles as I handle the tube. See this photo:

 

2021-05-06_15-58-25.png.cb27461aedf69f2e799027bf26671627.png

 

 

Looks like flakes from the mica spacers.  I haven't seen this before on any of my tubes.  Yours must be special 🙂  Or maybe you need to change shampoo?

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It could also be flakes coming off the anode plates or heater wire. I've seen this before for new production tubes only. Vintage ones nope. Well not yet any way. What all this points to is the high likelihood that one of the operating points on the amp is outside spec. It could be the heater or it could be the B+ just going to the V2 position. For the tube to fail in 3.5 months (Feb-May) suggests to me the amp is the main contributor. 

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12 hours ago, BLAH BLAH said:

 

The silvery coating is OK - the residue in the tubes is a sort of flakey substance. Googling suggests that it is most often caused by a vacuum leak from the tube, which apparently can have various causes. Obviously, I have no idea at all what it could be ;) I am betting for now it is a faulty tube (because that is a less painful option) and am keeping my eye closely on the bias and, of course, the tubes themselves. If one of the new EL34s starts to exhibit the same problem, then it has to be the amp. I am planning to take it in at some point to have that resistor fitted so they guy can check it thoroughly for other potential problems at the same time. 

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One thing to mention, @Zed Zed, is that during my research of the EH 6CA7, I came across many warnings that this tube is or was notoriously unreliable. There was even one tube dealer that stopped carrying them because of too many failures. It seems that quality has improved since those posts, however. Do yours happen to have date codes?

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Posted (edited)
49 minutes ago, echorec said:

One thing to mention, @Zed Zed, is that during my research of the EH 6CA7, I came across many warnings that this tube is or was notoriously unreliable. There was even one tube dealer that stopped carrying them because of too many failures. It seems that quality has improved since those posts, however. Do yours happen to have date codes?

 

I will check the tubes and boxes for codes and report back.

 

Unfortunately, no date codes. Nothing on the tube itself other than the manufacturer's logo and branding.  Nothing on the box other than the little sticker with the test result data and a bar code. Searching the bar code number returns nothing. I bought the tubes from vivatubes.com so I think I will contact them and see what they say. I'm not especially bothered about a refund or replacement (although I won't say no) because the TS EL34Bs I have replaced them with are, IMO, superior.

 

EDIT: OK, I have emailed the seller and sent him the photos I posted here. I'll update the thread on the response I get which, hopefully, will be positive.

 

EDIT 2: The dealer you mention is our very own Jim of ValvesnMore I think?  Jim McShane - is that the guy? Certainly, assuming for now that my issue is the tube and not the amp, my experience seems to bear out the unreliability thing - just 3 months old, not abused etc.

 

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Posted (edited)
1 hour ago, Zed Zed said:

 

I will check the tubes and boxes for codes and report back.

 

Unfortunately, no date codes. Nothing on the tube itself other than the manufacturer's logo and branding.  Nothing on the box other than the little sticker with the test result data and a bar code. Searching the bar code number returns nothing. I bought the tubes from vivatubes.com so I think I will contact them and see what they say. I'm not especially bothered about a refund or replacement (although I won't say no) because the TS EL34Bs I have replaced them with are, IMO, superior.

 

EDIT: OK, I have emailed the seller and sent him the photos I posted here. I'll update the thread on the response I get which, hopefully, will be positive.

 

EDIT 2: The dealer you mention is our very own Jim of ValvesnMore I think?  Jim McShane - is that the guy? Certainly, assuming for now that my issue is the tube and not the amp, my experience seems to bear out the unreliability thing - just 3 months old, not abused etc.

 

 

The more I re-read reviews and anecdotes on various forums, the more I realize date codes probably wouldn't matter because premature failures are reported all the way back to the 2000s. I think the seller referenced in that thread is: http://www.mcshanedesign.net/ , not the same guy that does the videos. He is still, as of last month, not selling those tubes for the same reason. He warranties tubes for 90 days, so that says a lot about his feelings on reliability of these. I only mention all this because premature failures were a common theme when I looked into these tubes and were the main reason I never ended up trying them. You'll still need to figure out what happened with yours and, fingers crossed, hopefully it was just the tube and not the R8.

 

 

Edited by echorec
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2 hours ago, echorec said:

 

The more I re-read reviews and anecdotes on various forums, the more I realize date codes probably wouldn't matter because premature failures are reported all the way back to the 2000s. I think the seller referenced in that thread is: http://www.mcshanedesign.net/ , not the same guy that does the videos. He is still, as of last month, not selling those tubes for the same reason. He warranties tubes for 90 days, so that says a lot about his feelings on reliability of these. I only mention all this because premature failures were a common theme when I looked into these tubes and were the main reason I never ended up trying them. You'll still need to figure out what happened with yours and, fingers crossed, hopefully it was just the tube and not the R8.

 

 

 

Yeah, he'd have been stung on mine if he'd offered a 90 day warranty on them - it failed at 89 days! :)  It's interesting that two of my tubes (the Tung Sol 6C8Gs) are 70 years old and still going strong, while the 89 *day* old tube is kaput. You may recall that I liked the Tung Sol 6C8Gs so much that I bought another pair as 'backup' in case of failure. Seems like I should have bought a couple of spare 6CA7s instead ;) 

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Jim McShane is very conservative and over criticises every singke modern tube he comes across for the exact same reasons above. He's been doing it for years and has been allowed to get away with it because all of us believe him. He does it so you can buy 'fully stress' tested tubes from him that have been screened for long hours in operation to confirm they won't fail but he still offers a limited 90-day warranty. Is that because he's placed the tubes under stress already? I bet you all didn't know he doesn't sell vintage types as he won't put them through the same 'stress' tests. He used to sell some Jan NOS stock made in the 1970's and 1980's that he claimed didn't need the stress test because they had already been screened by the US government. 🤣

 

Also, there are misnomers emerging in this thread that Tung-Sol vintage and Tung-Sol modern are considered to be the same. They're NOT 2 of the same. Tung-Sol modern is a trademark of Ekectro Harmonix Russia. All the tubes are being made in the exact same factory. They're for audiophool use only and nothing more or less. They don't go through any stringent test requirements before leaving the factory. We live in a society today where money is plentiful and most items we buy are consumable. Consider modern tubes in this category. I would even go as far as saying most amps coming out of China are in the same category. Expect failures in both camps. They're here to stay. Enjoy what you have for the time you have it working. When it gives way replace it. 🙂

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Posted (edited)

Back to the R8. If any of you toob rollers have spare pocket change available and don't want to buy consumable toobs here are some adorable looking 6SN7 subs from the yesteryear GEC Hammersmith UK factory that will probably outlast you and your kids.

 

https://www.ebay.com.au/itm/CV1102-GEC-true-NOS-x-rare-military-triode-akin-6F8G-one-pair-/203303070000

Edited by xlr8or
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2 hours ago, xlr8or said:

Back to the R8. If any of you toob rollers have spare pocket change available and don't want to buy consumable toobs here are some adorable looking 6SN7 subs from the yesteryear GEC Hammersmith UK factory that will probably outlast you and your kids.

 

https://www.ebay.com.au/itm/CV1102-GEC-true-NOS-x-rare-military-triode-akin-6F8G-one-pair-/203303070000

 

They are lovely - and not all that expensive. About 50% more expensive than the new ShuGuang Black Treasures I just bought for the 6SN7 position. Great looking tubes too - very similar to my Tung Sol 6C8Gs (which are totally a-ma-zing!). 

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2 hours ago, xlr8or said:

Back to the R8. If any of you toob rollers have spare pocket change available and don't want to buy consumable toobs here are some adorable looking 6SN7 subs from the yesteryear GEC Hammersmith UK factory that will probably outlast you and your kids.

 

https://www.ebay.com.au/itm/CV1102-GEC-true-NOS-x-rare-military-triode-akin-6F8G-one-pair-/203303070000

 

I bet these would kill any new production valves. I would save money, buy these and just enjoy the music 😊

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35 minutes ago, Jehuty said:

 

I bet these would kill any new production valves. I would save money, buy these and just enjoy the music 😊

 

They were specifically developed for use in the Avro Lancasters during WW2. Apparently, they were the most sophisticated comms valve of the time period.

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Posted (edited)

I think I have been stating the incorrect settings.

 

I set my bias at .35v which is 350mv, I guess that is 350ma? or is it 35ma? when we are talking about a 10r cathode resistor?

 

This gets me confused.

 

 

 

 

 

OK, expressed over 10 ohm resistor a measurement of .35v or 350mv equates to 35ma.

Edited by muon*
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Ian, that works out fine. You want 35mA or 0.035A. For a 10ohm resistor that's V = I x R = 0.035A v 10ohm = 0.35V = 350mV.

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20 minutes ago, xlr8or said:

Ian, that works out fine. You want 35mA or 0.035A. For a 10ohm resistor that's V = I x R = 0.035A v 10ohm = 0.35V = 350mV.

Yes, if I have it right .035v if a 1 ohm resistor? and .35v with a 10 ohm resistor.

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15 minutes ago, muon* said:

Yes, if I have it right .035v if a 1 ohm resistor? and .35v with a 10 ohm resistor.

 

Yes - that's correct. 👍

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9 hours ago, Jehuty said:

 

I bet these would kill any new production valves. I would save money, buy these and just enjoy the music 😊

 

WARNING: AHEAD LIE DANGEROUS WATERS - PROCEED AT OWN RISK :) 

 

It's an interesting idea that nobody can manufacturer a vacuum tube properly any more. I can see that in the immediate aftermath of the move to transistors manufacturers would lose interest in tubes - a market they would see as finished, or at least in terminal decline. Compare it loosely with the shift from analogue LPs to digital CDs. But once it becomes evident that there is a newly resurgent or continuing market for a product, usually some enterprising manufacturers will step in to fill the vacuum (excuse the pun), much as we have seen with, for example, turntables.  Once this happens, there is no real reason that I can see why the new manufacturers would be incapable of making a quality product. That is not to say, of course, that there will not be shoddy products turned out for a fast buck, which happens in every field of manufacture, all the time. But equally, in every field that I can think of, good quality manufacturers exist, serving a more discerning market.

 

When tube amplifiers ruled the roost, and SS came along and usurped their hold on the market, the initial SS amplifiers were mostly less than good. Ditto with early CD players. There was a learning curve. Eventually, SS amp and CD player manufacturers figured it out and began to make high quality products which were offered in a diverse marketplace in which high quality and low quality existed side by side. It was up to the buyer to decide which end of that scale he was going to choose, or could afford.

 

So today, as with analogue content and hardware, eg turntables, there is a large demand for quality valves across the world. Why would we believe that no contemporary manufacturer would be able to step in to meet this demand with a good quality product? After all, there is a huge market for valves/tubes in the world of guitar amplification and it would seem strange to believe that guitar players universally did not care about quality or reliability.  And these musicians, by and large, cannot take a chance on vintage tubes - they have to have equipment which can stand the rough and tumble of touring and the high expense of recording in studios, where they can't afford equipment downtime when they are paying a huge sum of money, by the hour, for the use of the facility.

 

So, while I can easily accept that vintage tubes are excellent, I struggle to accept that no modern tube can also be excellent. Manufacturers today have vastly superior technology to assist them than existed decades ago. Robotised production has brought down costs and increased quality in every field of manufacturing (take cars as a good example of that, or medical care). Computer-aided design and manufacture has revolutionised numerous industries - take loudspeakers for example where a quality exists today at a standard and at prices inconceivable 40 years ago. Why would these things, which have come to pass in pretty much every industry, fail to apply to the manufacture of vacuum tubes?

 

Note that I am not suggesting that vintage tubes cannot sound magnificent, and maybe more magnificent than many (or even most) modern tubes, but since they generally cost several times more money, this is to be expected really. It is inappropriate to compare a $30 modern tube with a $300 vintage tube - apples and oranges. Obviously, there will be many cheap modern tubes which are of poor quality, just as there are many cheap anything that is of poor quality. But that does not preclude the possibility of excellence if comparing like with like. Just because something is old does not automatically render it good,  just as something which is new is not automatically poor.  It is up to the individual to examine the options and choices and make the best decision he or she can within the bounds of their knowledge, information and budget.

 

Personally, I have some vintage tubes which are magnificent (my Tung Sol 6C8G Black Bottles for example, or my MELZ 6SL7s) and have just recently bought four current production Tung Sol EL34Bs which are showing tremendous promise. And, according to online tracking, today I will receive a pair of new ShuGuang Black Treasure CV181 (6SN7 equivalent) which, by all accounts, are fabulous-sounding tubes. Time will tell how they sound or how reliable they are.  Would I also love those tubes Kirk linked to?  You bet your a$$ I would. If they are still around in a couple of months, after I have burned in the ShuGuangs, I would love to buy them and try them. If, as more likely than not, they are not around, I may be able to stretch Kirk's generosity and ask him to help me find something similar. And as a bonus, I absolutely love the look of those tubes which feature a grid cap (like my 6C8Gs). :) 

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Posted (edited)

China and Russia kept making tubes for the military as they are not effected by EMPs, throughout the cold war period at least, while consumer goods moved to transistors as they were smaller and cheaper to produce..

 

Military standards needed to be tougher and withstand more rigorous environmental conditions with tighter tolerances in many cases than for HiFi, and a lot of the coatings and stuff used in many old NOS tubes are not allowed to be used in manufacturing today due to health and safety and environmental reasons.

 

Even before transistors tubes needed to be pretty rugged as consumer products like TV's and Radios had to be transported over big distances across country and over seas in some cases. But you will find among old tubes the military verities made to more stringent specifications with longer life.

 

Modern consumer manufacturing is based on affordable manufacturing as this increases the profit/bottom line, and means being more competitive.

 

Edit: Note that many of the old names are now owned by New Sensor that started out as an American distribution business, and most of the tubes or all are made in just maybe two factories located in old Russia.

 

BTW, zed zed, the old Philips TDA1541 chip was difficult and expensive to manufacture, the main reason they moved to easier and cheaper chip manufacturing processes.

Edited by muon*
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@Zed Zed I am not great at writing too long. Thank you for your in-depth response, that shows a lot of respect and I do appreciate it. So, apologies in advance if my response is not as sophisticated.

 

I've been playing valves since 2009, not as long as Kirk or the other valve connoisseurs here but I did spend my money on new production valves. Luckily, before I spent too much on them, I met a number of SNAers who had had decades of experience with valves and they quickly showed me how the NOS valves were simply better all around in terms of musicality and my preferences in sound. So from there, instead of buying the latest and greatest, I started collecting vintage audio gears. If I ever need money, I could easily sold them at the price I paid for or even higher because old valves (especially NOS) do appreciate in time. So, for me there really is no reason to buy new production valves.

 

Just a food for thought, if the new production valves are better, why do people still pay a lot more money for the Western Electric 300b? And no, it's not because they are rare. And remember, the market is not stupid and it is not a fluke to have people willing to pay that much money for countless times.

 

Enjoy your journey! 😃

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