|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.0.212.232
In Reply to: RE: Consider this DC circuit for 2A3 posted by Frihed89 on November 21, 2014 at 23:15:48
Frihed89:In 1947, Jack Robin and Chester Lipman published a small $2.00 book entitled “Practical Amplifier Designs”, sub-titled “45 Proven Circuits for the Technician and Experimenter “. One of their circuits in this book actually was a two stage direct coupled (6SF5 - 6B4G) all triode amp shown by you in this thread, and probably similar to the “Fi” amps of today .
A couple decades later, I imagine Asano and Shishido were obviously privy to that book and schematic you posted.
The Serious Stereo amp is somewhat different.
Topology wise, it does NOT take the B+ for the driver tube from the top of the Final's tube cathode. ( Not stabilized and too low in VDC ). No, not at all. It uses a R/C network off of the main B+, a slightly higher B+, and feeds the front end tube from a "cleaner" and higher B+, a R-Dropper you may call it. Dennis voltage choices and op points are ideal for highest fidelity and longevity.
Additionally, unlike many a DC amp I have seen, Dennis employs a simple shunt regulator, a no feedback type, such that it lowers the Z of the driver supply to wonderful levels. This gives his amps a GREAT low end, and stabilizes the mu of 100 driver tube, advantageously. So, the driver stage is totally shunt regulated, unflappable, and has a mVAC content of under 2 mVAC !!
Then, there are other DF topology audio circuit tweeks that I am not at privy and hesitant to discuss, but very very effective from my experimenting with them.
Dennis, in my experience, has the "most perfect" topology and execution of any of these DC amps I have studied, by far. And I am not just talking about his B+ filtering to the finals, LSES !!!
Just A-B Dennis' DC 2A3 amps, particularly his latest ones !!!, with ANY other DC amp. That tells the tale. Lakerfan uses a mildly-updated early DF amp, and reported what he hears to us - and he claims he has owned 50 SETS !!
Jeff Medwin
Edits: 11/22/14 11/22/14Follow Ups:
set up a separate SS forum or a DC 2a3 forum and spare us.
Hi Jeff.I know you mean well, and like what you hear, but all I wanted to do in the first place was to contribute something useful to the guys here.
What I didn't want was for me or my equipment to become a "Hot Topic" discussion item.
Everyone on here has the right to his own favorite topology, and right or wrong, ordinary-sounding or not, he also has the right to believe in it.
In fact, believing in what one is doing is a key step towards improving anything, so give these guys a break.
I don't wish for this "praise-to-the-moon", and then "kick-to-the-Gutter", "scientific", then "non-scientific" cycle to persist any longer--it's not useful to forum members, many of whom are plenty smart enough to understand both camps..
The Flame-Outs are getting increasingly psychotic to say the least-- even to the point of denying the common IEC socket wiring topology that EVERYBODY uses!.
Let's all return to reality and common decency and do things objectively, and show due respect for different apps, methods, and listening preferences..
---Dennis---
Edits: 11/22/14
OK, will do and co operate. Cheers !!
Jeff Medwin
Please keep the craziness in the crazy thread below. This thread doesn't need it.
Get a room...separate forum. did Gusser not say he stands corrected regarding IEC as you acknowledged you could not see it was properly connected in the photo. He did not "deny" something common. Has Don Garber been around this forum shilling?
Edits: 11/22/14
Moving forward would be not to bash or slight another design.
Someone on one side of this conflict has recognised that the bickering needs to stop. There is a small prospect of improved relations; maybe even civility, heaven forbid.
To both sides: if you simply can't let it go and move on, let us know what outcome you would like from this petty conflict and how - perhaps with our help - you are going to achieve it. But really, trying to square a ledger of past grievances rarely in my experience delivers productive outcomes for either side of a conflict. It is currently rather miserable - move forward.
Act like the intelligent professionals you claim to be.
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
After all the discussions below must we still endure this in every thread here?
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: