Hi,
I recently bought through this forum a set of AKSA 55N amp. modules.
I noticed that the emittor resistors are nice quality Dale 1 ohm, 1%, 5W.
Are these the correct values ? 1ohm seems high, the DF will be lowered.
The only amp I've seen 1 ohm resistor were on the Hiraga le monstre.
Should I buy some 0.47ohm or 0.33, 0.22 ohm ?
Thanks,
Eric
I recently bought through this forum a set of AKSA 55N amp. modules.
I noticed that the emittor resistors are nice quality Dale 1 ohm, 1%, 5W.
Are these the correct values ? 1ohm seems high, the DF will be lowered.
The only amp I've seen 1 ohm resistor were on the Hiraga le monstre.
Should I buy some 0.47ohm or 0.33, 0.22 ohm ?
Thanks,
Eric
Member
Joined 2009
Paid Member
Hi Eric
I have not seen the schematics but follower output (if that is the case) and high feedback factor (high open loop gain) makes this emitter resistor value a negligible effect on DF...
But anyway a DF >= 20 is probably enough for most speakers...
Good luck with your new amp.
Fab
I have not seen the schematics but follower output (if that is the case) and high feedback factor (high open loop gain) makes this emitter resistor value a negligible effect on DF...
But anyway a DF >= 20 is probably enough for most speakers...
Good luck with your new amp.
Fab
Last edited:
Hi Eric,
The original design used 5W ceramic block wire wound Noble 0.47R. That is what I would recommend you use.
However, the set you built might not be quite the same as the original, because I never did use 1R. But to re-iterate Gareth's comment, DF is over-rated and I always found that if you had a DF more than 40 you lost a lovely decay from the bass and midrange which never sounded very natural to me. I concur with Fab, he is correct in my experience too.
I'm quite sure with 1R it will sound very nice, because there is plenty of global feedback around that amp and the feedback - around 60dB of it - reduces the Zout and around 50milliohms, which would drive a rusty nail to symphony levels........
It's really amusing, the AKSA was created in January 2000, and just now I have revisited it using very different active components, different output stage (mosfet) and recompletely redesigned feedback and compensation. I am calling it the Super AKSA, SAKSA for short (!!?) and after all my perambulations with this circuit in the last week it sounds about five times better than the original. I hope this too will become a classic!!
Cheers,
Hugh
The original design used 5W ceramic block wire wound Noble 0.47R. That is what I would recommend you use.
However, the set you built might not be quite the same as the original, because I never did use 1R. But to re-iterate Gareth's comment, DF is over-rated and I always found that if you had a DF more than 40 you lost a lovely decay from the bass and midrange which never sounded very natural to me. I concur with Fab, he is correct in my experience too.
I'm quite sure with 1R it will sound very nice, because there is plenty of global feedback around that amp and the feedback - around 60dB of it - reduces the Zout and around 50milliohms, which would drive a rusty nail to symphony levels........
It's really amusing, the AKSA was created in January 2000, and just now I have revisited it using very different active components, different output stage (mosfet) and recompletely redesigned feedback and compensation. I am calling it the Super AKSA, SAKSA for short (!!?) and after all my perambulations with this circuit in the last week it sounds about five times better than the original. I hope this too will become a classic!!
Cheers,
Hugh
Attachments
Last edited:
Hi Hugh,
Problem solved ! The first transistor's base had a cold joint therefore was floating...
Please PM me regarding the required bias for each amp, my emitter resistors are 1 ohm instead of 0.47ohm. What voltage value should I be looking for if I connect my voltmeter across the 2 resistors.
BR,
Eric
Problem solved ! The first transistor's base had a cold joint therefore was floating...
Please PM me regarding the required bias for each amp, my emitter resistors are 1 ohm instead of 0.47ohm. What voltage value should I be looking for if I connect my voltmeter across the 2 resistors.
BR,
Eric
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.