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1 minute ago, planet10 said:

As we well know, measured distortion does not even come close to being able to describe how a device sounds. You have to listen to them connected to real loudspeakers.

 

And if youbelieved they were you wouldn’t be building amps & such with tubes.

 

dave

As above, not saying high distortion amps - like a lot of high power tube amps- don’t sound good they just aren’t high fidelity. But as an speaker building friend use to say; “pick the distortion profile you like and stay with it”.  The fidelity “thing” never struck him me until I built my first Holton 300W amp and experienced utterly clear transparency. Once you hear it it’s hard to go back. Doesn’t stop me dropping in my 2W 6L6 SE UL power amp though for a week or so at a time. 

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Stereo Subs & Two Way Monitor Build   It’s been slow going on my two way monitor with stereo sub build but I’ve finally finished finished one of the two subs!!!   The subs are 10inch CSS drive

Finally finished my 6sn7 preamp. 😀 not a bad outcome considering 50% material was recycled. Thanks a lot mwhouston for schematics.

Thanks Pete Sure! Pretty much just used common spray acrylics (cans) for the whole job. Not shy of using 2k but just trying to save on costs.  After the cabs where routed i gave th

I have heard a number of very low distortion amplifiers, and they were all too often not very good. Each amplifier has to be considered on its own merit, driving loudspeakers — they ar e system, and one can often get lower measured distortion in compination than when measured separtly.  On example is a low R[/sub]out[/sub] amp driving a speaker designed to be used with a high R[/sub]out[/sub]  amplifier vrs a more suitable amp even thou the 1st can have measured distortin magnitudes lower lower than the 2nd.

 

dave

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“pick the distortion profile you like and stay with it”.  That's pretty good "rule of thumb" for anyone

 

Interesting thing - I got boards over from Tom Christianson (Neurochrome) to build his version of "ye ol' gainclone lm3886" amplifier using his exact BOM - the really surprising thing about this extraordinary low distortion version is how neutral it sounded - not flat and irritating like the old Crown and such "low distortion amplifiers", but a very nice sound indeed - not exactly my "cup of tea" into Fr drivers but never-the-less, a very pleasant surprise indeed - go figure.

 

I have the 150W modules (NVx-200) for bass from Tassie - another low distortion amp that's excellent for bass -  a tricked out F6 for mids/tops from >150Hz.   (FAB, or WAW, Dave?)

 

Glad to see your health is in the mend, Dave.

 

 

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Tom brought his big 200w prototype to diyFEST one year. A really good sounding amplifier (but perhaps a touch to low an Rout to match my speakers, but skinny speaker wire should fix that.

 

Not sure what FAB is, but the mains have been mostly our big A12pWeN/A7.3eN MTM WAWs. But there are. a few other WAW and alot of sngle (and double) driver FRs.

 

When i get my diyAudio Store diy version of the FW B4, i’m going to swap these in (almost as good a sound, but prettier and the shape better suited to my room). This pic not my room.

 

Ellipsa-1st-veneered.jpg

 

Ellipsa-inside-1000.jpg

 

dave

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13 hours ago, planet10 said:

I started out w Firstwatt when a friend loaned me his 1st gen ACA. I loved them. Then i got 2 newer ACA with a bit more power. Then a confluence of events allowed me to get a SIT-3 which is an incrediable amp. Curiousity has me wondering abou tthe ones i between like your F5.

 

dave

The F5 is a different beast to anything I have heard before. I understand why people say it is too bright but even with my speakers I was up until 4am listening last night so it isn't fatiguing. It is very impressive with good recordings and punishing to bad ones. In some ways it reminds me of my Halcro in detail retrieval it's not my perfect amp/sound but I am very happy with it and will tinker with it a little more and try the F6 or Aleph J when I can and swap them in :)

If you have the itch and like the ACA and SIT-3 then go for it. It is great that many can be built in the same chassis with same PSU

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2 hours ago, planet10 said:

Ellipsa-inside-1000.jpg

 

Wow, those look like something from an aircraft factory. Beautiful form and construction.

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Yes Dan, the F5 has lots of good things about it - upgrading the power supply makes a  big difference and also trying some of the 'audiophool' resistors in the signal path makes a big change too - you can "soften" it off a bit with a Cap Multiplier supply and  the Manganin resistors and still maintain the high definition levels  - maybe worth considering if you upgrade it.

 

Sorry Dave, Full (ranger) with Assisted Bass - now knowns as WAW - I'll get there in the end!   Marvelous craftsmanship, your speakers.

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1 hour ago, HdB said:

Yes Dan, the F5 has lots of good things about it - upgrading the power supply makes a  big difference and also trying some of the 'audiophool' resistors in the signal path makes a big change too - you can "soften" it off a bit with a Cap Multiplier supply and  the Manganin resistors and still maintain the high definition levels  - maybe worth considering if you upgrade it.

 

Good to know thank you. It is so time consuming reading through the DIY audio forums for what can be done.

Do you mean just the transformer in regard to the PSU or the filter circuit too?

Will look into resistors, cheers

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4 hours ago, planet10 said:

Built by my partner Chris. After we got back together i wasn’t allowed to build cabinets, just design them :^)

 

dave

Balance the hobby/job with life. Make everyone happy and you’ll be happy too. And you will be better creative. 

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Yeah Bunno, The F5 has been around quite a while now and many variations, yes, and much info to plow thru if you're so inclined. 

I found the basic F5 with Nichicon power caps and Dale resistors to be a bit bright for me so I started playing with it to change the sound to a softer sound without losing any details or transients to suit my system and ears - this may not be what you want to don't rush to make changes yet. 

 

There are currently a couple of projects about building Cap Multipliers power supplies for amps like these and these mostly drop 2 - 5 volts on each of the rails - if you have something like 24volts now (+/-24v), the drop won't make much difference to the amp's operation unless you're running inefficient speakers, a 'head-banger', etc so the existing transformer will be okay - the recommended size was 18v sec @  300 va (for both channels) but many people have used either 2 trannies or a bigger 500va unit - if you're not using big amounts of power, stay simple for now.

 

I found the bridge diodes  did make a difference to the sound (but many people think I'm crazy - could be right too!) - I was happy with the MSRF 860s and 1560s but ended up with the low loss, low noise Shindengen Schottky bridges - only a small change.

 

Resistors - I'd better mention now that some of these fancy resistors are a crazy price - the "U-beaut' naked Vishays (TC2575) are somewhere around $18 each and the Manganin ones I mentioned used to be around $6ea - you don't need many for this amp but it quickly adds up.   It's something to maybe consider later or if you've built a Jim's Audio kit with Nova power caps, for example.

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After building a way over specced F5 for another in a 5U I would go for the two massive PSs and double (300VA) trannies but maybe cheap Rs. I also liked the thermistors on the 250V both active and neutral for surge protection. 

 

 

4C770F1A-6709-4E20-AA55-206224DCD611.jpeg

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Got a compactish full horn system up and running.

I bought the bass horns which come from a Wireless World published design from 1970 .They are a folded horn which I am guessing were designed to be used in corners.These sat in my shed for a few months.Frankly I was not expecting much from them .I got around to replacing the 12 inch woofers with some Fostex FW305 s which I had already and which have been described as good in horns.The Edgar 500Hz tractrix midrange loaded with Dynaudio dome midranges and bullet tweeters I have had for over 20 years.

What has surprised me is how low the bass goes in these.Even not in corners.

I am measuring good bass down to at least 40Hz I was not expecting much below 100hz .And it is really good tight clean bass .[See in room response].Yes it needs some tidying up but the bass extension is surprising.

IMG_0522.JPG

IMG_0525.JPG

Edited by THOMO
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@HdB@mwhouston

 

Thank you both. That is great info and made my research a lot easier.

 

I have a 360VA Noratel and a 500VA Sedlbauer. The 500VA is going to be a tight squeeze to use current vertical mount so will probably need a layout change. Also have the Vishay bridge rectifiers so they are definitely going in soon.

 

Yeah that is crazy prices for resistors but still relatively cheap compared to buying retail amps/upgrades so might be worth a try? Doubt my mismatched trannys is a good idea though.

 

The F5 turbo would be something else. What are the insulators you used? The keratherm ones?

 

This is my thermistor setup though not done by me

96394404_937457786719126_5819797406111236096_n.jpg

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3 hours ago, Bunno77 said:

@HdB@mwhouston

 

Thank you both. That is great info and made my research a lot easier.

 

I have a 360VA Noratel and a 500VA Sedlbauer. The 500VA is going to be a tight squeeze to use current vertical mount so will probably need a layout change. Also have the Vishay bridge rectifiers so they are definitely going in soon.

 

Yeah that is crazy prices for resistors but still relatively cheap compared to buying retail amps/upgrades so might be worth a try? Doubt my mismatched trannys is a good idea though.

 

The F5 turbo would be something else. What are the insulators you used? The keratherm ones?

 

This is my thermistor setup though not done by me

96394404_937457786719126_5819797406111236096_n.jpg

Just bought a bunch of them myself. 

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Our Mr Cowan came up with some gems, eh - he did some really excellent amps too

 

I'd suggest you stay with the single trannie if you can fit it - there's vertical brackets available or just get one of those heavy duty timber building brackets and knock the barb down - works like a charm.

 

About those mains wires/thermistor connector,  I'd suggest adding an insulating patch underneath - can't be too careful - also, those thermistor sometimes get really hot and you might need a ceramic connector - Jaycar keep them.

 

The one resistor I'd suggest you play with is the 220R gate stoppers - if you can, get some Kao metal films for a slightly softer sound, or maybe Beyschlaggs (the Roe 'resista' ones) if you can find them - I've got some here if you want some.

 

I have the keratherms but for some reason I still like using the messy 'goo' or those grey pads for temporary setup.

 

   Something else I've never managed well is the mounting bolts/washers for the power fets, plus, often changing the boards out,  so I use those dual transistor clips (RS number 504-0609) and cut in half -  the ridgid ones that work okay too.

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19 minutes ago, Red MacKay said:

Any pics of that 4P1L pre in action?

Nope. This is 6SN7 pre with power supply in same chasis.
4p1L pre will need two Larger separate chasis. I am thinking supratek style two chasis. 
 

 

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27 minutes ago, Red MacKay said:

Any pics of that 4P1L pre in action?

No chasis. Just left runnning sitting on the floor. Need to find two chasis.

C0FEFCA9-E593-4A1D-AF68-E75B386B4878.jpeg

Edited by SumonKabir
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How do you find the sound of the 4P1L tube.

Also any microphonics from the tubes.

I'm sure you are being careful but Please mount the PCB on a piece of plywood for testing.

Steve.

 

 

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On 02/05/2020 at 2:39 PM, mwhouston said:

Hope the member doesn’t mind me putting this up but here is a newly completed F5 turbo with some high end parts. Pretty well every tweak you could include has been. A way over specked double PS makes this a dual mono build.
 

5U heavy extra thick enclosures with steel sub-chassis. Two 300VA shelled trannies.. 16 X 15A supper fasting diode pairs and 192,000uf of caps snubbed a number of times. .  Don’t want to say to much before the member has a chance to hear but very impressed so far. 

77D97D15-7CDF-4F81-B61B-DEC823C2C173.jpeg

This my amp that I asked Mark to build for me. I decided that I wanted the F5 Turbo V1 which is a standard F5 with higher PSU rails to achieve a few more watts. I think this one would be approx 38w output. And also the large dual mono PSU

- PRP resistors amp boards

- Charcroft Z Foil input resistors

- PSU resistors Panasonic/Riedon

- PSU caps Epcos 

- 2x 400va Toroidy shielded TX's

- NOS Toshiba J Fets

 

I've had a few listens to it so far just to put a few hrs on it. In short this is the best amp I've heard with my Zu Druid speakers. Some say the F5 is bright/harsh but I don't hear a hint of either. I'm certainly pleased that I spent all the $$ as it has resulted in a cracker of an amp, I'm truly impressed.

 

 

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18 minutes ago, Gryffles said:

This my amp that I asked Mark to build for me. I decided that I wanted the F5 Turbo V1 which is a standard F5 with higher PSU rails to achieve a few more watts. I think this one would be approx 38w output. And also the large dual mono PSU

- PRP resistors amp boards

- Charcroft Z Foil input resistors

- PSU resistors Panasonic/Riedon

- PSU caps Epcos 

- 2x 400va Toroidy shielded TX's

- NOS Toshiba J Fets

 

I've had a few listens to it so far just to put a few hrs on it. In short this is the best amp I've heard with my Zu Druid speakers. Some say the F5 is bright/harsh but I don't hear a hint of either. I'm certainly pleased that I spent all the $$ as it has resulted in a cracker of an amp, I'm truly impressed.

 

 

For the four to six hours I got to hear this BIG build in my main rig I was throughly impressed. It may lean a little to the bright side but only just and this is through my Altec/Faital horns. Also it is a very pleasant lean and just releases more detail in the music.

 

If this was the only amp I could keep I’d die a very happy man. Fabulous bass that goes way deep and and full. Mids are really excellent treble extension unlimited. Detail comes right though. 
 

Based on what I have heard I’ve ordered a pair of boards myself. Not sure I’m going to the extremes and expense of this build but if I did it would be money well spent. So glad it has found a happy home and I’m hoping one day to hear it with the Zus. Sounds like a killer combo. 

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I'm toying with putting a Tube-i-zator valve output stage in my other BIII DAC and I need a transformer with 150V & 9V secondaries for this built. I sent an email to Harbuch Transformers who have made custom transformers for me in the past, I haven’t heard back so I thought I'd have a go at making one myself. In the end I thought it would be much easier to buy a transformer of the right size and put on the 150v secondary myself. Of course, this could all end up in the bin :)

I bought a 120VA, 9-9v transformer from Element 14 for less than $40 and have removed one of the 9v secondaries. I tested the 9v outputs before I dismantled it, and as usual I have more volts out than the rated voltage, 10v in this case, with 230v coming in. There is another benefit in doing this, I can remove some of the turns on the other secondary and reduce the output voltage to 9V. It turns out that about 98 turns gets you 10 volts out, which means I’m going to need about 1400 turns to get what I want, hmmm thats a lot of turns, better not loose count 😊

The wire for the 150v will cost between $15-$25 dollars so all up it should cost about $60. The last couple I had made cost close to $200 plus postage and their output voltages were higher than I ordered. I need to choose the wire size and then get about 200lm of it. I may save $150ish but I’ll earn my money doing the winding. All a bit of fun.

Tran 3.jpg

Tran 4.jpg

Tran 2.jpg

Tran 1.jpg

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How critical is the 150V ?  A quick google shows 120 to 150 V for that circuit board.   I was thinking, what about using back to back transformers and take the voltage from half the second transformer's primary?  If you want to boost it a bit, you could remove or add turns to the 9V connection between the transformers.  Just thinking out loud...

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The original Tube-i-Zator (which I made some years back) talked about 120v-150v but the latest board only notes 150V so I thought I'd stick with that. Always happy to hear a thought  :)

 

I need 0.1amp out so I thought I'd go for the 30awg which has a maximum of 0.142amp. I will probably wind the wire on a stick doubled over first so I only have to go around 700 times, yay.

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10 hours ago, DQ828 said:

 I sent an email to Harbuch Transformers who have made custom transformers for me in the past, I haven’t heard back

 

I know the feeling here...

 

6 weeks ago I sent an enquiry to Peter at Harbuchs, nothing.  Then two weeks later I rang him and we spoke, I then emailed details again.  ...Over a month has passed and I am still waiting.

 

Also 6 weeks ago, I rang RF Waves in Perth enquiring prices on a pair of 600va Noratel trannies.

 

I was soon informed by the gentleman on the other end of the phone that I was conversing with an experienced electrical engineer and that I was wasting my money and only needed 300va trannies, they would be plenty.

 

I was expecting to pay $350ea or whatever for the size I asked for.  All that was required was to a quote a price   No - not too hard. surely?  ...Well, apparently it was.

 

So what is wrong with these people?  They don't want to sell product?  Is my $700 or so, so small that they don't need it?  I was after all asking for a standard product in their range with no time limit specified to supply as I understand I would be a lesser sale in their business.

 

So now I guess I must head overseas to source what I want.  A great shame.  Toroidy in Poland have a great reputation amongst audio buddies for being totally professional and supplying a great product.  Plitron in Canada also come to mind.  Any other suggestions?

Edited by Red MacKay
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1 minute ago, Red MacKay said:

 

So now I guess I must head overseas to source what I want.  A great shame.  Toroidy in Poland have a great reputation amongst audio buddies for being totally professional and supplying a great product.  Plitron in Canada also come to mind.  Any other suggestions?

 

 

For a couple of decades I used Harbuch for power toroids.  However, for my current build, when I approached Peter, I got the same kind of runaround.

 

So I ordered from Tortech.  No stuffing around - and they shipped them quickly.  So that's who I'll be buying toroids from, from now on.

 

But if it's EI-type traffos you want - I recommend:

  1. Voller Transformers, in Moorabbin, 9553-3222, or
  2. Southern Electronic Services, in Dandenong, 9706-4202.

 

Regards,

Andy

 

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10 hours ago, DQ828 said:

I'm toying with putting a Tube-i-zator valve output stage in my other BIII DAC and I need a transformer with 150V & 9V secondaries for this built. I sent an email to Harbuch Transformers who have made custom transformers for me in the past, I haven’t heard back so I thought I'd have a go at making one myself. In the end I thought it would be much easier to buy a transformer of the right size and put on the 150v secondary myself. Of course, this could all end up in the bin :)

 

I bought a 120VA, 9-9v transformer from Element 14 for less than $40 and have removed one of the 9v secondaries. I tested the 9v outputs before I dismantled it, and as usual I have more volts out than the rated voltage, 10v in this case, with 230v coming in. There is another benefit in doing this, I can remove some of the turns on the other secondary and reduce the output voltage to 9V. It turns out that about 98 turns gets you 10 volts out, which means I’m going to need about 1400 turns to get what I want, hmmm thats a lot of turns, better not loose count 😊

 

The wire for the 150v will cost between $15-$25 dollars so all up it should cost about $60. The last couple I had made cost close to $200 plus postage and their output voltages were higher than I ordered. I need to choose the wire size and then get about 200lm of it. I may save $150ish but I’ll earn my money doing the winding. All a bit of fun.

 

Tran 3.jpg

Tran 4.jpg

Tran 2.jpg

Tran 1.jpg

A brave man. 

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Red,  I have used both Piltron and Toroidy, both are excellent.

Another is Amplimo (Toridal transformer.com) but in the current climate shipping is going to be a killer.

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Free shipping?  Well there is over half the cost saved there!

 

1kV.  Awesome.  It's all about current capability...  What are you using for a soft start?

 

Thanks to everyone with suggestions.

Keep them coming in so everyone can share our options.

 

 

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