Hi Franz
I am not familiar with JC-2 but it looks like there is a mistake in that circuit.
You have source of n channel jfets connected to drain of p channel jfets.
Is is it meant to be like that?
Actually, when I need a buffer, I use a B1. When I need a line amplifier with some gain: a JC-2
There is not difference between source and drain with jfets.
An externally hosted image should be here but it was not working when we last tested it.
Have you read a report on the different performance when jFET is reversed D for S?
Could you link us to that report?
I believe that RF jFETs can be asymmetrical, but we are using audio jFETs.
Would the bf862 qualify as a possible asymmetrical RF jFET?
This is true 😛 a few people will... Actually, there are some that are symetrical or whatever but, some that are not. I believe there are "long channel" and "short channel" types and it's the long channel ones that are not reversable.
I have used the BF862 in reversed D & S without any problems.
If you know how a JFET is being constructed in silicon, you will also understand why it works.
Patrick
If you know how a JFET is being constructed in silicon, you will also understand why it works.
Patrick
Hardly perfect, but why don't you start a thread on the topic?
Supposedly this thread is about changes in the F5 power amp and how they sound...
_-_-bear
Supposedly this thread is about changes in the F5 power amp and how they sound...
_-_-bear
I have planned a F5 with BUZ900/905, mounting the pcb now... Is any changes needed with the BUZ mosfets? (also have IRFP here, for next version..)
Arne K
Arne K
hey, hang on
are you saying that we could also reverse just one of the jfets, and not the other 😕
because this would be quite nice
meaning that it would much easier to mount them "face to face", as commonly suggested, very strongly 🙄
Du Franzl,
auf dem ETF habe ich von einer deiner Nachbarn verstanden Du lernst schon seit langem.
Google translate:
You Franzl
on the ETF I understand from one of your neighbors, you learn a long time.
You Franzl
on the ETF I understand from one of your neighbors, you learn a long time.
My impressions of F5 and Aleph J
Last few months I built few Pass amps - namely F5 and Aleph J. I built the stock version of F5 as well as Toshiba output variant. FWIW, I would like to write few of my personal build & listening impressions on the stock versions of F5 and Aleph J.
From a hardware standpoint, the F5 is easier to build, has lesser components and simpler schematic. The F5 runs hot, but not as hot as Aleph J. Latter also requires matched output pairs, whereas one need not have matched output pairs to build a F5. I have used 500VA toroids with stock Pass power supply with 60000uF on each rail of 24V DC.
Connected to Fostex FE206E based Back Loaded Horn speakers, I have listened to these amps extensively last few months. Both sound terrific and to my mind, is the best sound I have heard all my life. Both the amps require very high quality source material and can expose any weakness in the front end very quickly. So one gets onto another journey of fixing the front end right, and then may be speakers next.
To my ears, Aleph J sounds fuller and richer and slightly less forgiving when playing vinyl. On the other hand if one were to describe F5 - then I can use the term "High Definition" or "Ultra High Resolution", to define it's sound. Extremely unforgiving on it's source. Relatively speaking, little weakness in lows, but highs and mids to die for. I know one has 2nd order and the other has 3rd order harmonic distortion pattern, but it does not matter to me. They both are one of the best amps one can build and probably far exceed commercial amps in mid to high end bracket.
YMMV.
Thanks Mr. Pass for sharing your design and getting great amplification, within reach of common DIYers like me. Next on my plate is J-BOZ...
Cheers.
Last few months I built few Pass amps - namely F5 and Aleph J. I built the stock version of F5 as well as Toshiba output variant. FWIW, I would like to write few of my personal build & listening impressions on the stock versions of F5 and Aleph J.
From a hardware standpoint, the F5 is easier to build, has lesser components and simpler schematic. The F5 runs hot, but not as hot as Aleph J. Latter also requires matched output pairs, whereas one need not have matched output pairs to build a F5. I have used 500VA toroids with stock Pass power supply with 60000uF on each rail of 24V DC.
Connected to Fostex FE206E based Back Loaded Horn speakers, I have listened to these amps extensively last few months. Both sound terrific and to my mind, is the best sound I have heard all my life. Both the amps require very high quality source material and can expose any weakness in the front end very quickly. So one gets onto another journey of fixing the front end right, and then may be speakers next.
To my ears, Aleph J sounds fuller and richer and slightly less forgiving when playing vinyl. On the other hand if one were to describe F5 - then I can use the term "High Definition" or "Ultra High Resolution", to define it's sound. Extremely unforgiving on it's source. Relatively speaking, little weakness in lows, but highs and mids to die for. I know one has 2nd order and the other has 3rd order harmonic distortion pattern, but it does not matter to me. They both are one of the best amps one can build and probably far exceed commercial amps in mid to high end bracket.
YMMV.
Thanks Mr. Pass for sharing your design and getting great amplification, within reach of common DIYers like me. Next on my plate is J-BOZ...
Cheers.
Thanks for putting your impression out there!
If I may say so, if you like the resolution of the F5, you'll like the BOZ-J.
I'm working on my second BOZ-J with higher quality parts: "naked" Vishay resistors, Mundorf caps (Supreme for by-pass) and stepped attenutator. Should be an interesting comparison also.
Vince
anilva congrats on your build.
Wery interesting point yo make.
Tell me more please
What differencies with the Toshiba sound vise and component wise?
What do you listen to?
What front end?
What are your faw test records?
What components you use rail voltagges bias?
Wery interesting point yo make.
Tell me more please
What differencies with the Toshiba sound vise and component wise?
What do you listen to?
What front end?
What are your faw test records?
What components you use rail voltagges bias?
Waiting for few things to reach me to start the BOZ-J build. Thinking of adding a remote control based input selector and volume control. I have seen a few of them on eBay. Any views?
Cheers.
Toshiba was little better than IRFPs, but I need to check them out better. I am building a dual output pair Toshiba F5 with jfet degeneration and cascoding (not bridged). Will post my experience with that.
My music is classic rock, contemporary rock, indian classical, film music etc. My front end is a marantz cd player and a technics SP-10 turntable. 24 volts rail voltages and stock bias for F5.
If it's a short signal path and the noise is low, I'm all for it.
Thought this might be of interest. A friend turned me on to this company- Bent Audio
They have a motor control for DACT and Shallco attenuators.
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