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Dear All,Last weeks I’ve been busy making ‘prototype’ boards for the all new amp I’m building. I wanted to test a few things, so I wired up some stuff… And as always it became a ‘beautiful mess’ I would like to share.
First impressions. AWESOME!! This is the first all DHT amp I have breadboarded with a low DCR (not low C and H yet) PSU.
FYI, this is an integrated Aa (series battery biased) cap coupled to VT25 (cathode bias) cap coupled to a 300B (fixed bias). Aa and VT25 heaters are supplied via a VCCS, Aa is loaded by a CCS/resistor combo, the VT25 is choke loaded.
Thanks for looking and sorry for the bandwidth!!
(select right button / show images show the compete image on screen).
Regards,
Nickel Core
Follow Ups:
Now that is one wild assed breadboard! I've got to show this to my wife, 'cause she will count her lucky stars after she sees this. I bow to the master.
If so, the student has surpassed the Meister!If not - he's going to be awesome after some coaching from you!
I think you missed your calling. Push-Pull monoblock I hope, so we can see two of these side by side. It is pretty awesome. What is the circuit? I think I missed that thread.
...what you see is a integrated SET amp.3 stages, input xfrm-> PEC Pot-> Aa-> cap-> 10Y-> cap-> 300B
First stage has series battery bias, second stage cathode bias, third stage fixed bias.
First stage CCS loaded, second stage L loaded.
Filaments via a VCCS for the first two stages, third stage AC.
PSU:
First and second stage: CLC one per channel (6X4 rectified)
Third stage LCLC one per channel (GZ37 rectified, the OPT size chokes you see on the back are 10H / 5R chokes).
Fixed bias, CLC one per channel (6X4 rectified)Each filament / VCCS combo has its own transformer (there is another rather large heater/filemament transformer inside the amp you can't see).
Aa runs @ 185V / -3.6V bias
10Y runs @ 340V / -26V bias
300B runs @ 450V / -90V biasYou see a humpot too besides the 10Y's because I want to check if i can get away with AC on the driver too.
Basically this a breadboard on which I want to try a few things for a slightly over the top integrated amp (with phono-stage) I'm currently building.
The rest of the system:
AN-Lexus sig. speaker rewired with AN-Vx and upgraded with hemp drivers
AN-TT Three reference with RS-A1 arm and Kondo-IOJ
AN-S8 step-up
DIYHifi LCR Cole Riaa
All interconnects are AN-SOGON
Regards,
Nickel Core
have you checked what kind of hum you get with AC heating on the 300b? I am soon going to try some cancellation methods to get mine down lower than it is currently. this is also a 3stage 300b amp, but only 2 are dht (choke loaded 6b4g driver).
hello zarniwoop !an idea. why not sub in a 2a3 for the 6B4G so you can run your driver on AC at 2.5 VAC / 2.5 A.
that should sound even better than a DCed Ef 6B4G I would guess.
hi,
Even with a 2a3 I doubt it would work to use AC heating. In theory, the hum from the two ac-heated dhts should cancel somewhat when they are coupled in series as common-cathode stages. guess the driver overwhelms that effect since its amplified further.i'm going to try to stay with AC on the 300B. I still maintain that its not possible to get a really quiet amp with AC heating dhts (in SE) without some tricks. Maybe at 2.5v its tolerable.
Well, with the 10 turn hum pots I'm able to get down to unhearable hum level at my listening position with my 97dBA speakers (you can feel some 50hZ hum when touching the cones though).
I am sure it will be beautiful in a chassis too.
its more beautiful than mess. way cool.i would love to leave my amp like that permanently. its like teslas workbench or something. great symmetry of that layout... breadboard of the gods.
123
But here in the NL we really all have 1Mbs DSL or more at home.
.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
What exactly do you mean by too large?Doesn't it load?
I have my screen set at 1024 X 768 and the pics more than fill the screen. I have to scroll to see the whole picture.I'm guessing that's the complaint. I have none.
Nice amp. Now build it all again with a normal PS. :-)
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
LOL: Wait till you see the PSU's for my new amp.. You will have a bad day!! ;-)When you select right mouse button -> show picture you will get the whole picture to fit on your screen.
"When you select right mouse button -> show picture you will get the whole picture to fit on your screen."I knew that.
I saved this pic at 72DPI and 10" wide.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I resize images usually to 700 pixels and less than 60KB file size for audio-forum use. This'n's 600 pixels wide.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
I love the WAF :-)
.
Hi.My wife would have divorced me 33 years ago if I fouled up my residence like this!
My workbench (adjoining my audio den) is in a far end corner of my house basement, out of sight of my home-sweet-home upstair. I got to tidy it up everytime I finish my session. Or curtain lectures will follow.
She hate soldering fumes & my HiFi noise.
c-J
PS: What human rights we men should have? Check up my post below.
Probably no pets either.
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