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Perhaps a decent 10k pot? You could, if to be a permanent set up, also use any pot of reasonable value to find the right attenuation, pull it out of circuit and measure it, then replace with two suitable resistors of good quality.
Pot for LF55
Filipe,
I normally use a RK27 Alps rated to 20k.
They are conductive plastic and last well. All pots have some influence on the sound quality, the best are attenuator, but they are VERY expensive, like the DACT.
Hugh
Filipe,
I normally use a RK27 Alps rated to 20k.
They are conductive plastic and last well. All pots have some influence on the sound quality, the best are attenuator, but they are VERY expensive, like the DACT.
Hugh
Good point with the resistor in series, that would minimize impact on SQ.
Hugh thank you or the recommendation i will try one of those.
Hugh thank you or the recommendation i will try one of those.
I built my Aksa 55 just over 20 years ago! and I use it to this day. I recently became paranoid about the age of the power supply caps and replaced them, (like for like) but I think the old Rifa PEH200s were still going strong - such is their reputation. At the time of building I used some better components - nonpolar black gates, expensive replacements for C1 and C8. I understand that a number of upgrades became available for this amp. Is it still possible for me to obtain/apply these upgrades now?
WOW!! That's a few years back, the 55 was my first commercial product and was released in mid-2000 so that was one of the early ones!
Send me an email and I can discuss how to improve the AKSA a little more. I'm at aspen01 -at- optusnet.com.au
Thanks for the post!
Hugh
Send me an email and I can discuss how to improve the AKSA a little more. I'm at aspen01 -at- optusnet.com.au
Thanks for the post!
Hugh
Hi, Hugh - I sent an email to the address you gave me a couple of days ago. I'm at alan.calderwood@virgin.net. Thanks.
Houdi,
So i am quite puzzled with resistor sourcing, i thought to ask opinions .
Until now i identified 1/4w , 1/2w , 1w resistors by its size alone. But when on 2 different orders from Mouser i get these, i dont know who to believe anymore:
All these were ordered as 1W resistors. I suspect only the blue ones are 1W.
Can a 1W resistor be that small ? It looks like 1/4w to me. Does it depend on the brand ?
I ordered some Vishay Dale resistors, CMF55 and they are spec'd to 1/2w.
Their size seems to equal a 1/4w resistor !
So i get puzzled by resistor physical size. These Vishay CMF55 were ordered both from Mouser and a German supplier, and both clame to be 1/2w.
Any thoughts ? I wouldn't want to destroy Hugh's amp because of resistor ratings.....
So i am quite puzzled with resistor sourcing, i thought to ask opinions .
Until now i identified 1/4w , 1/2w , 1w resistors by its size alone. But when on 2 different orders from Mouser i get these, i dont know who to believe anymore:
An externally hosted image should be here but it was not working when we last tested it.
All these were ordered as 1W resistors. I suspect only the blue ones are 1W.
Can a 1W resistor be that small ? It looks like 1/4w to me. Does it depend on the brand ?
I ordered some Vishay Dale resistors, CMF55 and they are spec'd to 1/2w.
Their size seems to equal a 1/4w resistor !
An externally hosted image should be here but it was not working when we last tested it.
So i get puzzled by resistor physical size. These Vishay CMF55 were ordered both from Mouser and a German supplier, and both clame to be 1/2w.
An externally hosted image should be here but it was not working when we last tested it.
Any thoughts ? I wouldn't want to destroy Hugh's amp because of resistor ratings.....
Last edited:
I am more convinced that different technologies in production of resistors lead to different sizing, i was just not expecting such huge differences.
Regarding for example the 180 ohms 1W , bought from Mouser :
PR01000101800FA500 Vishay / BC Components | Mouser Portugal
A 6.5mm length resistor looks like a 1/4W but spec says its a 1W ! 😱
Their datasheet specifically says :
FEATURES
• High power in small packages (1 W / 0207 size
to 3 W / 0617 size)
So the question that still hangs is for Hugh : is it ok to use these on the LF100 ?
Look good quality, known brand....its just they are tiny 😀
Cheers all
Filipe
Regarding for example the 180 ohms 1W , bought from Mouser :
PR01000101800FA500 Vishay / BC Components | Mouser Portugal
A 6.5mm length resistor looks like a 1/4W but spec says its a 1W ! 😱
Their datasheet specifically says :
FEATURES
• High power in small packages (1 W / 0207 size
to 3 W / 0617 size)
So the question that still hangs is for Hugh : is it ok to use these on the LF100 ?
Look good quality, known brand....its just they are tiny 😀
Cheers all
Filipe
Hi Filipe,
Yes, you can use them, but they are EXPENSIVE, Vishay strikes again.......!!
As better and better construction technique comes along, resistors seem to becoming smaller and smaller. These are rated to 1W, so they should run pretty hot!
They will be just fine. However, the bootstrap resistors and the fb resistors should not use metal oxide resistors. I even use carbon composition on the fb divider, they promote even order rather than odd. XRK did a lot of work on this and found that CC resistors do more H2, which is 'warmer'.
I have a very large stash of Beyschlag resistors which were metal film resistors from the eighties. They always sounded very good.
None of your photos came through, Filipe, I'm sorry I could not see them. But I saw the Mouser/Vishay link you included.
Cheers,
Hugh
Yes, you can use them, but they are EXPENSIVE, Vishay strikes again.......!!
As better and better construction technique comes along, resistors seem to becoming smaller and smaller. These are rated to 1W, so they should run pretty hot!
They will be just fine. However, the bootstrap resistors and the fb resistors should not use metal oxide resistors. I even use carbon composition on the fb divider, they promote even order rather than odd. XRK did a lot of work on this and found that CC resistors do more H2, which is 'warmer'.
I have a very large stash of Beyschlag resistors which were metal film resistors from the eighties. They always sounded very good.
None of your photos came through, Filipe, I'm sorry I could not see them. But I saw the Mouser/Vishay link you included.
Cheers,
Hugh
Hi Hugh,
Yes maybe i did put the wrong link with pictures.
For reference, this is an example of 4 types of 1W resistors.
Different brands, different technologies, huge size difference. All Metal Film.
Yes maybe i did put the wrong link with pictures.
For reference, this is an example of 4 types of 1W resistors.
Different brands, different technologies, huge size difference. All Metal Film.
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Nice to have found this thread!!
I'm a new member here. One of the reasons for joining is AKSA. The sound signature does not age at all.
I have a very early version of this beautiful amp. Acquired it a couple of years ago; a pre-owned unit that has passed many hands and homes.
It needs a new enclosure, placement/layout and terminals.
As compared to commercial amps, this one makes my speakers sing happily.
One of the sweetest sounding amps that I've owned or heard.
Cheers,
Raghu
I'm a new member here. One of the reasons for joining is AKSA. The sound signature does not age at all.
I have a very early version of this beautiful amp. Acquired it a couple of years ago; a pre-owned unit that has passed many hands and homes.
It needs a new enclosure, placement/layout and terminals.
As compared to commercial amps, this one makes my speakers sing happily.
One of the sweetest sounding amps that I've owned or heard.
Cheers,
Raghu
Which one do you have, Raghu?
(It should be written on the PCB.)
I've been through:
* AKSA 55N+ and AKSA 100N+
* Lifeforce 55 and Lifeforce 100
* NAKSA 80
* and, currently, Hugh's diyAudio offering - the Alpha Nirvana (40w into 4 ohms).
All are still in use except the Lifeforce 100 monoblocs which, due to me changing my spkrs, I no longer need.
Andy
Member
Joined 2009
Paid Member
@andyr @Bigun
I think it is the original AKSA55. Will open it up later today and take some pics.
The last time I opened the top cover and looked at it was 2 years ago.
At the time the assembly resembled a 6th grade science project 😀.
The unit needs some TLC. So planning a new enclosure, an IPA bath and reorientation of boards, transformers and connectors.
Since I don't have any documentation, I'll have to work carefully.
Cheers,
Raghu
I think it is the original AKSA55. Will open it up later today and take some pics.
The last time I opened the top cover and looked at it was 2 years ago.
At the time the assembly resembled a 6th grade science project 😀.
The unit needs some TLC. So planning a new enclosure, an IPA bath and reorientation of boards, transformers and connectors.
Since I don't have any documentation, I'll have to work carefully.
Cheers,
Raghu
It says "AKSA Audiophile 55W Class AB Amp V2.1"
The PSU board is mounted upside down. Difficult to take a pic without dismantling. It has 4x4700uF Nichicon caps.
In the new chassis, plan to move the heatsink to the front, transformers to the midplane and PSU board to center-back.
New RCAs and binding posts, an IEC and a led in front.
Cheers,
Raghu
The PSU board is mounted upside down. Difficult to take a pic without dismantling. It has 4x4700uF Nichicon caps.
In the new chassis, plan to move the heatsink to the front, transformers to the midplane and PSU board to center-back.
New RCAs and binding posts, an IEC and a led in front.
Cheers,
Raghu
Attachments
Ah yes Raghupb, that is the series 2 version of the AKSA 55!!
Looks well made too.
Brings back some memories, loved that amp myself.......... it had a wonderful midrange and top end, like a good motorcycle engine.
Hugh
Looks well made too.
Brings back some memories, loved that amp myself.......... it had a wonderful midrange and top end, like a good motorcycle engine.
Hugh
Hugh,
Take a bow Sir!! It is indeed a wonderful amp; wasn't kidding when I said "sweetest sounding" earlier.
I have rediscovered the joy of listening to music since acquiring it.
Love the "depth" of sound-stage it presents in my rig/room.
This birdie landed by pure chance in my home. I wasn't even looking out for an amp at the time.
A friend who had loaned it from the previous owner was adamant that I hear it out. Found out that is was up for grabs along with a tube preamp.
After listening to it, I could not send it back. I'm guessing it is at least 15 years old?
The current chain of components is:
Allo Digione (RPi based player) --> Parasound DAC --> Lyrita DHT tube pre (4P1L based) --> AKSA55 --> KEF R300 + REL T9i
I am planning to build a new DAC based on Soekris DAM1021. Alongside this project, will re-host the AKSA55 into a new chassis.
Having read the Audio Nirvana thread, makes me want to build that one too.
Will have to wait until the supply chain logistics ease up a bit for parts procurement.
Cheers,
Raghu
Take a bow Sir!! It is indeed a wonderful amp; wasn't kidding when I said "sweetest sounding" earlier.
I have rediscovered the joy of listening to music since acquiring it.
Love the "depth" of sound-stage it presents in my rig/room.
This birdie landed by pure chance in my home. I wasn't even looking out for an amp at the time.
A friend who had loaned it from the previous owner was adamant that I hear it out. Found out that is was up for grabs along with a tube preamp.
After listening to it, I could not send it back. I'm guessing it is at least 15 years old?
The current chain of components is:
Allo Digione (RPi based player) --> Parasound DAC --> Lyrita DHT tube pre (4P1L based) --> AKSA55 --> KEF R300 + REL T9i
I am planning to build a new DAC based on Soekris DAM1021. Alongside this project, will re-host the AKSA55 into a new chassis.
Having read the Audio Nirvana thread, makes me want to build that one too.
Will have to wait until the supply chain logistics ease up a bit for parts procurement.
Cheers,
Raghu