|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
24.127.166.64
In Reply to: RE: DIY PPP 6V6 Amp posted by drlowmu on January 11, 2017 at 20:19:31
I built this amp as monoblocks before. Sounded good.A lot more thought went into this amp that is not apparent in the picture. Being PP type, symmetrical is very important and more so than your SE amps. The power supply is not as critical as SE amps, but is of good design.
On a stereo chassis I tried separate power supplies for each channel and did not like the sound. Some others also like a single power supply vs two on same chassis. Unless monoblocks, two separate power supplies is a mistake on one chassis IMO.
Transformer and choke will have a ferrite lined steel cage. Under chassis top will also have a ferrite shield. Fields will not interfere with each other. Audio transformers will be outside the ferrite shield. This is a choke input power supply. Choke is rated 1.5 x the current being used. A second choke & oil capacitor separates the next stage from power tube stage. Paper/oil caps are used through out.
All leads will be same length. That is why the symmetrical layout. Lead length is important as you know.
Power supply and Heyboer M6 lamination custom transformer has been calculated in PSU2. B+ current capacity is more than double the demand. Choke is 27 ohms or close to your 20 ohm limit.
Input jack that will be in the front center is about two inches from input tube.
All wiring is silver including the ground wire. The ground is placed above the 6CG7s on ceramic standoffs for equal length to all amp grounds. The power supply ground connects at the far end and the ground terminates to chassis only at the input jacks.
The amp will perform fine and layout is not only symmetrical, it is shielded to the point it acts like it is 3 feet square, but without bad news long lead lengths. The ferrite shields allow this short lead length. Which is more evil, long leads or ferrite sheet shielding.
Rectifiers are 5V4G. The rectifiers can be placed anywhere. It has no effect as to the location IMO.
Edits: 01/11/17 01/11/17 01/11/17 01/11/17Follow Ups:
Is the M6 transformer your PT or outputs?
Count me a fan of Heyboer!
M6 lamination power transformer was custom built by Heyboer Transformer. M6 provides more power output in smaller package vs standard power transformer M19 laminations.
The output transformers are Dynaco ST-70 (A-470) new manufacture exactly to old specs including winding turns, gage of wire, interleaves, etc from Triode Electronics. It is a great sounding transformer and accurate. Many audiophiles do not know this. Most audio transformers use M6 laminations.
I'm toying with remade Z565....haven't played with A470. The original Dynaco 70 circuit sure did measure well...damn popular amp as well...probably for a reason!
I like your build!!!
Z565 are one of the best audio transformers ever built.
I found the Z565 to have a very characteristic sonic fingerprint. Even with radically different topologies. I built an amp with a pair, and then upgraded to an output wound exactly like a Peerless S-265-Q, but with taps 20, 30% instead of the OE 50%. They cleaned the Z565's clock, and I got another pair made for the 4E27 amps, and got those with 20, 30 and 40% taps.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Interesting. At Electron One transformer tests the Z-565 had about a perfect square wave output and the Peerless had overshoot on the square wave test.
The Z565 are $190 a pair and the Peerless is about $1200 a pair if MagnaQuest still builds them.
Personally, I think the Dynaco A-431 sounds better than the Z565, but the A-431 are lower P to P impedance.
If the Peerless sound as good as you state, they are worth the money.
What you may discover at some point is that a winding house with an NC winder, and the winding details gotten from taking apart a transformer can make copies of anything that is put in their hands. I supplied an S265Q, and had them made in pairs a few times...:)
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
BTW- The shielding is called Giron. It will take the transformer and choke down to about zero AC field with two layers. I might as well have the power transformer & choke a 100 feet from the chassis.I also use a Corcom AC line filter.
Edits: 01/15/17
Thanks for the explanation, and I totally appreciate all the thought and care you put into this build.
A+++.
ALL silver wire is not needed, but silver is NICE in critical spots, I use a lot of m22759/11 these days, but I DO use silver in three spots (1) RCA jack to grid of input tube, doubled-up (2) My direct couple, about 19 AWG, tripled-up and (3) off the center tap of my DHT Ef XFR, tripled-up, under 2.5 inches, to the top of the 2A3's Rk resistor.
I hope you get great performance.
In my early DIY years, Bob Fulton mentored me on a P-P-P 6B4G amp, six outputs per channel and it was on eight chassis, weighed about 700 hundred pounds. Wouldn't play the big Fulton speakers at high levels. Now a days, ALTEC VOTT A7-800s and a single JJ 2A3-40 for Finals. Coming up soon, Q1 or Q2 - 2017, monoblock JJ 2A3-40 amps.
Have fun, I am !!
Jeff
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: