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Partial tear down of Willsenton R8


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On 20/09/2020 at 10:20 PM, demoiree said:

@2Dculture 

 

I just tried swapping out those 6sl7(with tungsol 6sn7) and the buzz seems to have reduced quite abit , so I suspect might be the stock 6sl7 quite noisy ? 

 

Will wait for some quality 6sl7 to arrive and report back my findings . 

6SL7, 6SN7 are basically like the 'interchangeability' of the 12AXX series of small tubes.  you can use them in eachothers circuits, but it will change the tubes operating point. it may work, it may not.

 Example, I have a pair of monoblocks that use a 12AX7 as the driver tube, if I replace it with a 12AU7, the amplifier will work, but, the circuit makes the 12AU7 start to overdrive, and anything more than 15 watts output (drive) the tube clips/distorts.

So changing them may seem to work, you might even prefer the sound? But that is the trade off.

 

quote from another forum (tubes).

"Just to add to Ed's thread: Same in only pin configuration and heater and plate voltage - but not the same operating characteristics. 6SL7's have a higher amplification and a lower transconductance than the 6SN7. The tubes are close enough, however, to WORK in each other's sockets if the amp or preamp just happens to be designed within their respective operating characteristics (my amp manufacturer informed me that the 6SL7 can work - but not substituted -in place of the 6SN7 although I haven't tried it). IMO, if your equipment is designed around one or the other, use just that. I doubt that any amp designer would be surprised to learn that another tube than spec'd sounds better in his topology."

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I am not an expert on tube amp like many on this forum however writing this blog to help those who are thinking of buying Willsenton R8 or those who owns it and want to know bit more about it. I am no

It came!!     ??????   Ordered November 22nd.  Arrived January 26th, by ocean.  (I was too cheap to pay the airfreight)    Off we go!  

An unexpected development here. Last night, I removed my MELZ 6SL7 tubes and replaced them with the Tung Sol 6C8G. I do not think I will go back to the MELZ.    I can hear the thuds of Stere

On 20/09/2020 at 12:47 AM, demoiree said:

as I found using the R8 via aux/cd, the sound stage is unbalance , bias toward the right speaker , as soon as I use my tube preamp via the pre in the bias is gone , the singer is smack bang in the middle .

 

Hello everyone, I'm new to the forum and also an R8 owner (for about two months now). Looks like there is some great discussion and information here, so thank you for that. @demoiree It's interesting you mention this because I am having the same issue with my R8, where the soundstage is slightly imbalanced, in favor of the right channel. The strange thing is that it is only noticeable on some music - Not everything. But when it is apparent, the vocals, which should be dead center, lean to the right, enough to be an annoyance. It is 100% the R8, as I have tested all sources, cables, and speakers, etc. It is also not the tubes, as I have done much rolling and the imbalance remains. Tube biasing is correct. Can anyone speculate as to what might be going on here? Could it be something inherent in the circuit design, or perhaps an out-of-spec resistor, etc.? I think I will eventually take it to my local hifi shop for service to try and sort it out.

 

Aside from this occasional annoyance, I absolutely love the R8. For tube amps, I had previously owned the Muzi X7, and before that, vintage McIntosh separates (C20 pre w/ss power). Both were great, but not the presentation I was personally looking for. I will say it took some effort to get the sound I love out of the R8. I remember my first thought when I listened to the R8 was "meh". A combination of "break in" and rolling the preamp tubes made it into a beautiful, musical amplifier. More specifically, it now has that deep soundstage I was chasing. It is very addicting. If I can just figure out this channel imbalance, then it will be perfect for me and I can stop obsessing over the next class a/b tube amp...

 

Btw, I am using it with Gold Lion KT88s. Next week I have Tung-Sol EL34Bs arriving, so that will be interesting to experience the difference. I'm very curious what I will prefer.

 

 

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1 hour ago, echorec said:

 

Hello everyone, I'm new to the forum and also an R8 owner (for about two months now). Looks like there is some great discussion and information here, so thank you for that. @demoiree It's interesting you mention this because I am having the same issue with my R8, where the soundstage is slightly imbalanced, in favor of the right channel. The strange thing is that it is only noticeable on some music - Not everything. But when it is apparent, the vocals, which should be dead center, lean to the right, enough to be an annoyance. It is 100% the R8, as I have tested all sources, cables, and speakers, etc. It is also not the tubes, as I have done much rolling and the imbalance remains. Tube biasing is correct. Can anyone speculate as to what might be going on here? Could it be something inherent in the circuit design, or perhaps an out-of-spec resistor, etc.? I think I will eventually take it to my local hifi shop for service to try and sort it out.

 

Aside from this occasional annoyance, I absolutely love the R8. For tube amps, I had previously owned the Muzi X7, and before that, vintage McIntosh separates (C20 pre w/ss power). Both were great, but not the presentation I was personally looking for. I will say it took some effort to get the sound I love out of the R8. I remember my first thought when I listened to the R8 was "meh". A combination of "break in" and rolling the preamp tubes made it into a beautiful, musical amplifier. More specifically, it now has that deep soundstage I was chasing. It is very addicting. If I can just figure out this channel imbalance, then it will be perfect for me and I can stop obsessing over the next class a/b tube amp...

 

Btw, I am using it with Gold Lion KT88s. Next week I have Tung-Sol EL34Bs arriving, so that will be interesting to experience the difference. I'm very curious what I will prefer.

 

 

Great to see another happy user of R8 ?. What preamp tubes are you using?

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@echorec

 

Thanks for sharing your experience here! regarding the imbalance I'm pretty sure it is the stock 6sl7 tube is playing up , but will confirm once I receive a new set of 6SL7. 

 

Have you tried using the pre-IN and see if the channel imbalance is still evident?

 

Keen to hear your experience with EL34!

 

 

 

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5 minutes ago, demoiree said:

@echorec

 

Thanks for sharing your experience here! regarding the imbalance I'm pretty sure it is the stock 6sl7 tube is playing up , but will confirm once I receive a new set of 6SL7. 

 

Have you tried using the pre-IN and see if the channel imbalance is still evident?

 

Keen to hear your experience with EL34!

 

 

 

It's definitely not the tubes as I have been rolling all of them and the imbalance is there regardless. But not every recording... It's strange. I have not use the pre-in, but will try that with my SS preamp later this week. Thank you for the suggestion!

 

In the case of the 6SL7s, I've used 2 different NOS sets so far. The first were a pair of Brimars, which I felt shrunk the presentation and were a tad muddy to my ears. My favorite so far are a matched pair of GE 6SL7GTs. These made a huge difference in 3D presentation and eliminated any harshness in the highs and mid-highs. I am completely happy with these, but rolling is so addicting, and I want to add some more 6SL7s to my arsenal, so I'm going to order a pair of Sylvania 6SL7GTs this week. Trying to decide whether to get the Gold Brand or Military Sylvanias... But, for sure, the stock 6SL7s are HARSH in my system. I do not like them at all.

 

For 6SN7s, I've rolled new Russian Tung-Sols and and NOS RCAs. The differences between all of them are fairly subtle, but I can hear more fine detail with the RCAs in. For example, the reverb trails from certain percussion can be heard decaying into the distance. Very cool.

 

Excited to hear EL34Bs!! I've never had an EL34 amp in my room, so it will be a new experience for me. It seems that most people will fall into either the KT88 camp or the EL34, and rarely both, so I await with open ears.

 

Ok, so I feel like maybe the R8 is a bit quirky, so here's another odd thing that happened a few days ago: We had some thunder storms and wind in the forecast, so unplugged all my gear for the day as a precaution. The next day, I plugged the R8 back in and turned it on immediately. The first power tube (V1) lit up like a red light bulb and I heard a bad electrical current sound out of my left speaker! The KT88 was getting full voltage and bias was not working on that tube, so I shut it off. I assumed it was a bad tube, so I changed the tube, turned it on, and it did the same thing to the new tube! I thought, ok there is something now wrong with the bias circuit for V1. I was devastated. Then I thought, maybe I should unplug the unit and plug it back in to see if it "resets" something. I did this, except rather then turning the R8 on immediately after plugging it in, I waited a couple minutes. Turned it on, and everything was fine. What the heck happened?!?! So let me ask: is turning the amp on immediately after plugging it in a bad thing? Because I feel like that had something to do with what I experienced. I am totally perplexed, but happy the problem has not returned. Btw, those tubes that went red work and sound fine. I do notice one of them has lost some bias when I check it, however.

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@echorec

 

Seems to be an issue with V1 socket or component on that tubes have dry solder or loose. I do that all the time and never had any issue like that. These kind of issue can happen when power filter caps are not discharged and you turn on the amp which surges voltage to tubes (and hence it is recommended not to turn on amp for 5 mins after turning it off).

With R8, as it has adopted floating earth for pre-amp heather voltage, main power caps discharges within few seconds of turning it off and should not have this issue.

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22 minutes ago, echorec said:

 

Ok, so I feel like maybe the R8 is a bit quirky, so here's another odd thing that happened a few days ago: We had some thunder storms and wind in the forecast, so unplugged all my gear for the day as a precaution. The next day, I plugged the R8 back in and turned it on immediately. The first power tube (V1) lit up like a red light bulb and I heard a bad electrical current sound out of my left speaker! The KT88 was getting full voltage and bias was not working on that tube, so I shut it off. I assumed it was a bad tube, so I changed the tube, turned it on, and it did the same thing to the new tube! I thought, ok there is something now wrong with the bias circuit for V1. I was devastated. Then I thought, maybe I should unplug the unit and plug it back in to see if it "resets" something. I did this, except rather then turning the R8 on immediately after plugging it in, I waited a couple minutes. Turned it on, and everything was fine. What the heck happened?!?! So let me ask: is turning the amp on immediately after plugging it in a bad thing? Because I feel like that had something to do with what I experienced. I am totally perplexed, but happy the problem has not returned. Btw, those tubes that went red work and sound fine. I do notice one of them has lost some bias when I check it, however.

touch wood , never occurred to my R8 , and I did immediately turn on after plugging in the cord . 

 

however this exact same thing happened yesterday on my recently acquired oldchen K3 ....  but according to the original owner it could be bias is off,  I still quite curious why and how it happened so suddenly for that particular tube socket. waiting for my bias tool to arrive and re-bias all the tubes and see if it re-occurs or not. if not @Atmaj could enlighten me... do you or know of someone good at trouble shooting tube amp issues like this? 

 

 

 

 

 

 

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@demoiree

 

Don't be scared with red hot tubes, it is common with tube amps ?. My take would be to first set the bias and check if it happens again. 

 

If it happens again then it may require a thorough investigation. One of my friend professionally repairs tube amps and he is in south east Melbourne. Please let me know how you go with bias setting and then we can ask him to have a further look.

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@Atmaj

 

Thanks for the reassurance , it all happens so randomly and scared the s**t out of me . 

 

Will do ! Finger crossed it is just the bias ! These days very hard to come by a  good tube amp specialist , especially in Melbourne. 

 

Will keep you guys updated !

 

 

 

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Tung-Sol EL34Bs came yesterday and I got to spend a couple hours with them, so I thought I'd share some first impressions. These came from Upscale Audio, who burns all tubes in for 72 hours, so I would consider these broken/burned in. My first thought was that vocals sounded different. More laid back or pushed back, like a couple feet behind the speakers, instead of level with the speakers like with the KT88s. There was definitely a small loss of "oomph" to the music and the soundstage is *slightly* smaller in width/height but is also slightly deeper, especially the center-fill of the stereo image. Overall I feel a sense of the sound being more lush and liquid, vs more powerful and detailed with the KT88s.

 

Anyway, those are some first thoughts. I'll report back in a week or so after I've had more time with them.

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8 minutes ago, echorec said:

Tung-Sol EL34Bs came yesterday and I got to spend a couple hours with them, so I thought I'd share some first impressions. These came from Upscale Audio, who burns all tubes in for 72 hours, so I would consider these broken/burned in. My first thought was that vocals sounded different. More laid back or pushed back, like a couple feet behind the speakers, instead of level with the speakers like with the KT88s. There was definitely a small loss of "oomph" to the music and the soundstage is *slightly* smaller in width/height but is also slightly deeper, especially the center-fill of the stereo image. Overall I feel a sense of the sound being more lush and liquid, vs more powerful and detailed with the KT88s.

 

Anyway, those are some first thoughts. I'll report back in a week or so after I've had more time with them.

That's great. Are these NOS or new production TS? I have heard good things about new TS 34Bs.

 

I am currently testing EH 6CA7 big bottle and GL KT77 along with some NOS Hitachi 6CA7 and Chinese 6L6. Still breaking in so can't comment at the moment but KT77 are sounding very dynamic for now.

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12 minutes ago, Atmaj said:

That's great. Are these NOS or new production TS? I have heard good things about new TS 34Bs.

 

I am currently testing EH 6CA7 big bottle and GL KT77 along with some NOS Hitachi 6CA7 and Chinese 6L6. Still breaking in so can't comment at the moment but KT77 are sounding very dynamic for now.

These are new production. I think they sound great, btw. It'll just take more time for me to understand the differences. I can already tell that the tubes I use in the R8 will be a sort of "flavor of the month" kind of thing. I like that. I like variety.

 

Looking forward to hear your thoughts on all those varieties! That should be a lot of fun.

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Enjoying rolling tubes ?

 

I already had TL 6SN7 and I like those so not comparing with any other brand.

 

Compared 6SL7s between Tung Sol, Sovtek, Philips JAN 5691 and NOS Sylvania 6SL7 GT. Sovtek is nothing but stock Chinese tubes. Exactly same in construction and sounds same as well. Only rebranded and labled as Made in Russia.  TL and Philips are good but Sylvania are brilliant.  Very smooth and clean sounding so settled on it.

 

In Power tubes, all EL34 versions are better sounding than KT88 (at least to my choice). So far Gold Lion KT77 are out. They are overly dynamic in mids. I like perfectly balanced fequency response so didn't like it much.

6L6 are good but sounding more like KT88. Vintage Hitachi 6CA7 are good but I have 2 only so out of question. 

I have added TungSol EL34B as well in the comparison. Now breaking those but sounding great as true EL34 out of the box with bit of a less high frequency response. Hope it will improve with breaking in.

 

Will update soon on final verdict. 

Edited by Atmaj
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Totally agree about the Tung Sol EL34Bs - The top (and bottom) is a bit rounded with the R8. In my case, they pair well with my speakers, which are bright and are detailed. Everything is smooth and balanced. Zero fatigue and I think they also sound great at night time volumes (I'm usually around 65-70db at night) and the soundstage retains its size. Those with speakers that lean warm/dark, or possibly neutral may find that these are not a great match for the R8, imo. But they really pair well with my metal dome tweeters. I haven't switched back to the KT88s yet as I am enjoying these too much.

 

That's interesting about the KT77s. Those were going to be my next purchase, but I'm thinking I'll pass since I seem to be overly sensitive to midrange imbalance or forwardness. Hmmm... Now trying to decide if I want to spend the cash on some SED Winged-Cs. They are really expensive, but the way I look at buying tubes is that I am buying them for future use, and probably future amplifiers, so I don't mind building a bit of a collection. If not those, then probably some GL KT88s...

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On 03/10/2020 at 5:06 AM, echorec said:

Totally agree about the Tung Sol EL34Bs - The top (and bottom) is a bit rounded with the R8. In my case, they pair well with my speakers, which are bright and are detailed. Everything is smooth and balanced. Zero fatigue and I think they also sound great at night time volumes (I'm usually around 65-70db at night) and the soundstage retains its size. Those with speakers that lean warm/dark, or possibly neutral may find that these are not a great match for the R8, imo. But they really pair well with my metal dome tweeters. I haven't switched back to the KT88s yet as I am enjoying these too much.

 

That's interesting about the KT77s. Those were going to be my next purchase, but I'm thinking I'll pass since I seem to be overly sensitive to midrange imbalance or forwardness. Hmmm... Now trying to decide if I want to spend the cash on some SED Winged-Cs. They are really expensive, but the way I look at buying tubes is that I am buying them for future use, and probably future amplifiers, so I don't mind building a bit of a collection. If not those, then probably some GL KT88s...

Yes, GL KT77 has a forward and loud mids compared to TL 34. I have Sonus Faber which are already rich in mids hence it was too much for me. 

 

If you want to add something, think of EH 6CA7 fat bottle. Very well balanced having mids of EL34 and solidness of both top and bottom end of 6L6. 

 

For me  now the battle remains between TS EL34 and EH 6CA7. I read somewhere that TS EL34 has a solid base after braking in so waiting for that.

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I wonder how easy it it would be to do a " True Bypass" mod of the preamp thus enabling the R8 to have an external preamp plugged into it... As it stands it is not meant to be ideal to plug an external dedicated preamp into the Preamp Section of an integrated. Having the versatility of a proper ' Power Amp Only' option opens up a world of possibilities.. Just a pity that feature wasn't correctly implemented from the start. Can it be sorted? 

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13 hours ago, bryansamui said:

I wonder how easy it it would be to do a " True Bypass" mod of the preamp thus enabling the R8 to have an external preamp plugged into it... As it stands it is not meant to be ideal to plug an external dedicated preamp into the Preamp Section of an integrated. Having the versatility of a proper ' Power Amp Only' option opens up a world of possibilities.. Just a pity that feature wasn't correctly implemented from the start. Can it be sorted? 

It can be done but will require some changes in the current circuit.

When you select Pre-In input:

  1. 6SL7's plate voltage and heater voltage need to be turned off (no point in burning those tubes if not using it.)
  2. The input shall be then directly routed to phase splitter section
  3. Additional circuitry will require to match impedance of 6SN7 input with Pre-amp output

However, this amp was designed primarily as an integrated amplifier and doing above changes will require precise calculations to make sure that it operates as Power amp only with max efficiency. An experienced tube amp designer will require to do that for sure.

 

Now the question is, is this change worth? this will only bypass 6SL7 pre-amp section so is that tube/section negatively affecting your sonic qualities of the pre-amp? I am sure it won't if you use quality tubes. 6SL7 is a twin triode but only one triode is used as a gain stage and other one is just a buffer with unity gain. R8 designer has designed this pre-amp section very well and in my opinion, that is one of the main reason this amp sounds so good and noise free.

Now a days it is rare to see any new amp using 6SL7 as these high gain tubes are bit difficult to handle for amp designer but has great sonic characteristics. 

 

On the other hand, I haven't seen any tube integrated amp which also work as a true power amp (not even Prima Luna does this). I would buy a true power amp if I am after that kind of configuration only.

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@Atmaj

 

the muzishare x7 seems to be dead quiet when switched to poweramp mode , unlike the R8 which i can hear instant hiss when operating in poweramp mode.

 

makes me wonder of the x7 is truly bypassing the preamp stage . 

Edited by demoiree
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11 minutes ago, demoiree said:

@Atmaj

 

the muzishare x7 seems to be dead quiet when switched to poweramp mode , unlike the R8 which i can hear instant hiss when operating in poweramp mode.

 

makes me wonder of the x7 is truly bypassing the preamp stage . 

I am doubtful. Having dead quite does not mean it is bypassing pre amp section. My Yaqin MC 100B was also quite and normal in Power amp mode but it wasn't true Power amp either. Yaqin has a resistor to drop the signal as well as removes the feedback to reduce gain in Power amp mode.

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X7-diagram.pdf

 

are we able to tell from the attached schematics that it bypasses the preamp stage? 

 

from my untrained eye , it seems to still go through the preamp tubes.

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You are correct.  Everything goes through 12AX7 which is a preamp tube.

 

The PRE IN has 47K in series resistor to drop the signal level. When S2 is turned on, RL1 takes input directly from Pre IN rather than volume control thus mimicking Power amp stage bypassing volume control .

 

image.thumb.png.32f57b8c3736ee2ed9d06f633e1e0d67.png

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@pretender

 

not fully , as i still finding ways to A/B test them without switching on and off each time i compare , as that really takes away my memory on some nuances that i hear. 

 

@Atmaj do you think is safe to mute and plug in a headphone to cut off the speaker output(without turning it off)? i can hear the speakers not getting any hiss or white noise when i plug in a headphone, does it mean that the transformer output has been cut?

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@pretender I can add a few comments regarding the X7 and R8. While I didn't have them both at the same time, I remember the X7's presentation distinctly. I thought it had a great amount of detail, was very energetic, exciting, and had nice control. It just wasn't different enough from my SS integrated. By different, I mean more "tubey" and holographic (holophonic?), which is specifically what I had in mind when I ordered it. The R8, on the other hand, ended up being exactly what I was looking for in presentation (after a lengthy break-in and replacing all tubes). It has the holographic qualities in well-recorded/mixed music I was looking for and, with the EL34's, can get lush and very 3D in the midrange, and is a nice contrast to the presentation of my SS amp. I need to experiment more with the R8's KT88s, but I think the X7 was a bit better when it came to detail and overall control, but I just didn't experience that holography the same way I do with the R8. There's just a very distinct sense of space and depth with the R8 in my setup. It is very addicting. So I think neither is better/worse and, as is the case with most hifi, it all comes down to personal preference and system synergy.

 

@demoiree Regarding headphone/speakers - I'll wait to see what Atmaj says, but I thought it was curious: When I plug headphones in, my subwoofer is still seeing some signal from the R8, as I can hear music weakly through the sub. So I must turn it off if I use headphones. On the other hand, my main speakers are dead quiet during headphone use. So, I'm also curious as to what's going on.

 

Also, I am not experiencing any hiss when using the R8 as a "power amp" as you are. Is this happening with other tube combos as well?

 

Well, I couldn't help myself and ordered some more preamp tubes. This time I have a matched pair of NOS TungSol 6SU7GTY coming -- The high spec military grade 6SL7. Anecdotally, these seem to perform at the same level, if not better, than Red Base RCAs, so it will be interesting to hear them in the R8's circuit.

 

 

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@echorec

 

thanks for sharing your experience with the X7 ! if comparing stock to stock , out of the box the X7 wins hands down, maybe due to higher quality JJ preamp tubes are fitted on the X7 . 

 

I still yet to start tube rolling the R8 as I want to grasp how the stock sounds first ,  having said , I bought some new production EH EL34 and tungsol 6SN7 , but haven't decided which 6SL7 I should get yet , from what i read the 6SL7 seems to be the heart and soul on how the R8 performs? 

 

regarding the white noise /hiss , i suspect it is due to the stock 6SL7 , will report back if the noise still evident once i roll in some quality 6SL7(which i still not sure what to get yet!)

 

 

 

 

 

 

 

 

 

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@demoiree Oh you have some fun ahead of you rolling the R8! I did not like the stock preamp tubes at all -- Confined soundstage, very little holography, and harsh in the upper mids and highs. Get a nice matched pair of 6SL7.  Definitely worth putting some money here. I've been using NOS because my system leans bright, and the NOS have all been smoother in the top, with an open and 3D soundstage. One thing I really appreciate about the R8 is that you can set it up to be lush and syrupy or punchy and detailed. Right now, I am enjoying the former with EL34b's and NOS preamps.

 

For subwoofer, I use an active sub which also has speaker level terminals, so I simply run a pair of speaker wire connected with bananas to the R8. My main speakers are connected to same R8 terminals with spades. It's a nice, clean way to do it if you're using an amp with no sub outs, like the R8.

 

 

 

 

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1 hour ago, demoiree said:

@pretender

 

not fully , as i still finding ways to A/B test them without switching on and off each time i compare , as that really takes away my memory on some nuances that i hear. 

 

@Atmaj do you think is safe to mute and plug in a headphone to cut off the speaker output(without turning it off)? i can hear the speakers not getting any hiss or white noise when i plug in a headphone, does it mean that the transformer output has been cut?

When you connect the headphone, speakers are disconnected and transformer output is diverted to headphone. It is very safe to do that.

 

If you want a less trouble then it is safe to disconnect speakers WHILE AMP IS ON MUTE. Just turn the volume control to min to be safe as well. 

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I am also done with my tube rolling with R8 and ended up with below configuration

 

6SL7 - NOS Sylvania 6SL7GT

6SN7 - new Tung Sol 6SN7GTB

Power Tubes - EH 6CA7EH fat bottles.

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1 minute ago, demoiree said:

Will check with him what else he has 

Yeah, check with him Neil is a nice guy. I think he still has Brimmer.

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6 hours ago, demoiree said:

@echorec

regarding the white noise /hiss , i suspect it is due to the stock 6SL7 , will report back if the noise still evident once i roll in some quality 6SL7(which i still not sure what to get yet!)

Yes, I believe you're right. On stock 6SL7, I hear a buzz/hiss when I put my ear near the mid woofer. When I rolled to a shuguang 6SL7, the sound went from a buzz/hiss to a hum. 

 

I barely hear the sound when I listen nearfield. Moving back a couple of feet, I can't hear either noises 

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The Tung Sol 6SU7GTY's arrived yesterday. Very neat looking tubes. These are the NOS brown micanol base, black glass military variants with matched triode elements. According to the seller, their burn-in is ~48 hours, so I have some time to go to make judgement. But 5 hours in I can already hear a subtle change in presentation.

 

I'm curious - The manual specifically warns against leaving the R8 idling for long periods of time. Why is this?

R8.jpg

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       Melody EL36S
      was just serviced By melody and tubes only have 8 hours of play on them. 
      i have the box it came in Aswell.
      pick up only due to the amp weighing 35KGS

      Photos:

      PLEASE READ
      If you include any reference to pricing whatsoever in this section (excluding RRP), your ad will not be approved If you are advertising multiple items, you must post one bulk price only, or post seperate ads for each item If you don't include photographs of the actual item being sold, your ad will not be approved You understand that a reasonable donation for selling fees is expected upon successful sale of your item
      - if you have previously sold items and not made a donation, your advertisement may not be approved.
    • By PG2019
      Item Condition: Very Good Shipping Options: Shipping is available at agreed cost. Suburb or Town: Melbourne State: Victoria Payment Method: EFT Reason for selling: NLR Further information:
      Selling my Bob Carver 350 Mono Amplifier, the amplifier was custom made in 240 Volts specifically so there is no need for a step down transformer. The condition is excellent hardly used, build quality is super,and each amplifier is individually handcrafted in the USA by "Tubular" Joe Bonin. Both amplifiers are finished in a lovely crimson red colour which looks absolutely superb.  Due to inherent design of the amplifier the Power Tubes which are the KT120 have a increased lifespan and run much cooler. 
       
      In terms of power, the amplifiers are rated at 350 into 8 and 400 into 4 more than enough power to drive the most difficult of speakers. I have all the original packaging so shipping should not be a problem. 
       
      If you have any questions or would like further information please do not hesitate to contact me.
       
      Price is Negotiable.
       
      PLEASE READ
      If you are advertising multiple items, you must post one bulk price only, or post seperate ads for each item If you include any reference to pricing whatsoever in this section (excluding RRP), your ad will not be approved If you don't include photographs of the actual item being sold, your ad will not be approved










    • By Atmaj
      Item Condition: Used Shipping Options: Pickup available but audition is not available. Suburb or Town: NARRE WARREN State: Victoria Payment Method: Cash on Pickup Reason for selling: Upgrading Further information:
      Up for sale is Yaqin MC 100B Integrated tube/Valve amplifier in excellent working condition along with $300 worth of upgrade.
      This is a true duel mono block amp having 2 seperate power transformer for each channel (hence there are 4 transformer rather than 3 which are on most of tube amps).
      Pre-amp tubes have been upgraded to Electro Harmonix 12AX7
      Coupling Capacitors have been replaced with Mundorf MCap Supreme 1uf. Capacitors are so big that they had to be mounted on chassis rather than the PCB (check photos).
      These 2 upgrade make this amp comparable to high end tube amplifier.
      A great sounding amplifier, ready to drive any speakers even less efficient speakers.
      FEATURES:
      Preamplifier uses SRPP amplification circuit and Nagao-type inverter, Cathode output circuit to promote.
      TWO connection mode: Ultra Linear Amplifier (UL) and triode (TR).
      Duel Mode: INTEGRATED AMPLIFIER mode or pure Power AMPLIFIER mode.
      The output transformer use audio special alloy and high strength Anaerobic enamel-insulated wire. It uses special coiling process.
      This amplifier is made with audio special Enthusiast electrolytic capacitor (MKP), capacitive cross-linked and high quality metallic resistance.

      SPECIFICATIONS:
      Performance Index
      Output power: 30W×2 (8O) Triode (TR) connection
      60W×2 (8O) Ultralinear (UL) connection
      Distortion: =1.5%
      Signal noise ratio (SNR): =90dB (A)
      Frequency Response: 5Hz~80KHz (-2dB)
      Input sensitivity: INTEGRATED AMPLIFIER mode: 0.25V / Power AMPLIFIER mode: 0.6V
      Vacuum tubes: KT88×4 6SN7×4 12AX7×2 (You can also replace it with 6550EH×4 6N8P×4 6N4×2)
      Dimensions: 390mm x 490mm x 190mm
      Weight: 30kg

      I have original box. Pick up from Narre Warren. Happy to post with buyers expenses and arrangements. 
       

      Photos:






       
      PLEASE READ
      If you are advertising multiple items, you must post one bulk price only, or post seperate ads for each item If you include any reference to pricing whatsoever in this section (excluding RRP), your ad will not be approved If you don't include photographs of the actual item being sold, your ad will not be approved
    • By mbd
      Item Condition: Excellent condition. Has lived most of its life in the box. Shipping Options: Pickup available but audition is not available.,Shipping is available at agreed cost. Suburb or Town: Melbourne State: Victoria Payment Method: Paypal, EFT Reason for selling: NLR Further information:
      I'm doing a bit of a cleanup, and have some gear that has reached the point of needing to be sold (thanks to all the sellers' items on here that have caught my fancy lately).
       
      This MF X-Can V3 was bought over 10 years ago and had its caps and tubes upgraded prior to purchase. Details about the mods that were done to it can be found in this thread and described by user 'deadie' whom I bought it from: https://www.head-fi.org/threads/benny-pimped-my-ride.190320/ - I paid around USD$400 at the time, and I have no idea what kind of market value it'd have today.
       
      In addition to the US power adapter, I also have UK adapter, and a UK->Australia converter, so you can use this in quite a number of countries with the additional bits.
       
      I believe I'm asking a very fair price on these, but feel free to reset those expectations if needed. 
       
       
      Photos:
       






    • By dr_carl
      Right now there seems to be a wealth of opportunities in the realm of tube audio here on SNA. Lots of top quality gear at excellent prices.
       
      Or am I  biased, having just gone further down the tube path?



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