Kenji, you seem to vascillate between a complete refusal to accept suggestions and a strong sense of inquisitiveness.
There are a only a handful of persons on this board who are more knowledgeable and patient than Hugh, and yet you largely disregard (by way of questioning most of his points without prerequisite effort to find out more on your own). When in doubt, given that the AKSA is Hugh's design, Hugh's recommendation is correct, as he has the insight into his design. Sometimes alternatives like Gaetan's are also correct.
Some preamps are prone to hum on a badly grounded amp. Otherwise, by virtue of their design may be much less, even "immune" to hum. In any case, your guarantee is a soundly grounded amp.
When putting together my AKSA, I thoroughly read up whatever resources I could find. in particular, as Samuel has pointed out, Doug Self's articles were invaluable to me. Please have a read. Ground Loops
After much pondering, I had to relate the theory to the AKSA's ground scheme. It wasn't too difficult. Hugh has implemented a very sound ground
. In the process, I slowly drew out the ground paths to convince myself why speaker ground and input ground needed to connect to different points, etc, etc.
By the time you start addressing the grounding again, there should be a very clear picture in your mind which ground path your input signal, output signal, power supply and chassis take. If you see more than one, that's where problems may occur.
Regarding logarithmic attenuators, again Google is your Friend. Google "audio taper" and there's really enough in the first six websites to answer just about everything you seem to expect us to spoonfeed you with. In reality the people here are being really nice because Hugh deserves the support.
There are a only a handful of persons on this board who are more knowledgeable and patient than Hugh, and yet you largely disregard (by way of questioning most of his points without prerequisite effort to find out more on your own). When in doubt, given that the AKSA is Hugh's design, Hugh's recommendation is correct, as he has the insight into his design. Sometimes alternatives like Gaetan's are also correct.
Some preamps are prone to hum on a badly grounded amp. Otherwise, by virtue of their design may be much less, even "immune" to hum. In any case, your guarantee is a soundly grounded amp.
When putting together my AKSA, I thoroughly read up whatever resources I could find. in particular, as Samuel has pointed out, Doug Self's articles were invaluable to me. Please have a read. Ground Loops
After much pondering, I had to relate the theory to the AKSA's ground scheme. It wasn't too difficult. Hugh has implemented a very sound ground
. In the process, I slowly drew out the ground paths to convince myself why speaker ground and input ground needed to connect to different points, etc, etc.By the time you start addressing the grounding again, there should be a very clear picture in your mind which ground path your input signal, output signal, power supply and chassis take. If you see more than one, that's where problems may occur.
Regarding logarithmic attenuators, again Google is your Friend. Google "audio taper" and there's really enough in the first six websites to answer just about everything you seem to expect us to spoonfeed you with. In reality the people here are being really nice because Hugh deserves the support.
Hugh (or indeed anyone else), you mentioned that the Benchmark was a good DAC. Have you tried this device with the AKSA to see how it sounds? I am slightly sceptical given my pervious bad experiences with other dac/preamps. I am convinced there is a matching issue here but nobody seems to be able to tell me why there should be any mismatch.
Hi Kenji,
No, unfortunately I haven't tried the Benchmark.
The AKSA uses a floating earth with back to back diodes and a 10R resistor. Only fb shunt cap, input bias resistor and input ground are floated, the remaining grounds are taken to Star Earth.
This is a conventional, widely used earthing schema with proven credentials.
I cannot understand why there should be a mismatch between the AKSA and the Benchmark, particularly if the Star Earth on the AKSA is correctly floated to mains earth via more back to back diodes and a 10R resistor, as supplied.
Cheers,
Hugh
No, unfortunately I haven't tried the Benchmark.
The AKSA uses a floating earth with back to back diodes and a 10R resistor. Only fb shunt cap, input bias resistor and input ground are floated, the remaining grounds are taken to Star Earth.
This is a conventional, widely used earthing schema with proven credentials.
I cannot understand why there should be a mismatch between the AKSA and the Benchmark, particularly if the Star Earth on the AKSA is correctly floated to mains earth via more back to back diodes and a 10R resistor, as supplied.
Cheers,
Hugh
Very likely, yes, but also dress of the wires, particularly input wires and power supply wires to the modules is important.
Be sure to check the hum is from the drivers, not from the trafos themselves.
Do you have a wire from Star earth to mains ground via back to back diodes and the 10R resistor (I believe I supplied it with the modules).
Cheers,
Hugh
Be sure to check the hum is from the drivers, not from the trafos themselves.
Do you have a wire from Star earth to mains ground via back to back diodes and the 10R resistor (I believe I supplied it with the modules).
Cheers,
Hugh
Hello Professor smith
If you still have hum problem, you really should do that important modification that I've described in this #43 post;
http://www.diyaudio.com/forums/aksa/151644-preamp-aksa-55-a-5.html#post1953640
You will alway have hum problems if you don't correct that ground loop problem in your input wires.
Bye
Gaetan
If you still have hum problem, you really should do that important modification that I've described in this #43 post;
http://www.diyaudio.com/forums/aksa/151644-preamp-aksa-55-a-5.html#post1953640
You will alway have hum problems if you don't correct that ground loop problem in your input wires.
Bye
Gaetan
This truly is a fascinating thread. Prof, WTF won't you take the good advice given to you by Gaetan and others? (You seem to have an extremely short-term focus, as in "Oh, it's no longer humming, so I'll stop", rather than "Yes, I had better sort out the wire routing and earthing once and for all, since people have spent their time to give me all this good advice".)
Just as a matter of record, I have 3-way active speakers driven by AKSA Lifeforce amps. And I happen to have a GK-1 preamp. My amplifier setup is conducive to hum and noise in the sense that I have 3 x LF modules plus an active XO (and 4 PSes) in the one box. (With a box behind each speaker.)
I get absolutely zero hum when listening to CD or tuner - even if you hold your ear 10cm away from each driver. So if you have hum or noise, it's because you built it wrong (or can't understand instructions) - not because Hugh's designs are defective.
If you live in or near Melbourne, by all means drop in and listen for yourself.
Regards,
Andy
You dont have a full understanding of the problem I have had. I did follow Gaetans method and it made things worse.
Anyway if this amplifier is so sensitive to mains noise that it wildly fluctutates in quality from one day to another, that cant be a good design. Furthermore why couldnt it include a simple filter on the power input if that was a known problem?
I'm not blaming anyone I was simply frustrated that I spent a fair amount of money and then never achieved total lasting satisfaction.
True, I don't have a full understanding of your situation. But I've built 4 AKSAs and never had any such a problem.
If Gaetan's methiod made it worse ... post about it. I'm sure he would be embarrassed that his advice had made your problem worse and would try to help you further.
AFAIAC, "this amplifier" has no problems with mains noise - as I said, mine are completely silent. But you do have to get earthing right - "DIY101", IMO.
Well I've spent a whole lot more money (with 4 amps in total) ... and have complete satisfaction.
As I read it you are blaming Hugh (for designing such a crap amplifier). In fact, you're blaming anybody except yourself. Regards,
Andy
I am not talking about mains noise. I am talking about the problem that the sound quality appeared to fluctuate and initially it was the black gates which were blamed. Then as time went on, the mains quality was blamed.
I already told him.
No not exactly. But the impression I get is that certain people find it very offensive
if I do not praise this product and company. Sometimes customers aren't satisfied and I don't think it's fair to be attacked for expressing that.
Prof, let me assure you, the sound quality" on my LFs does not fluctuate.
In fact, it is so good that someone who came to visit (he was curious to hear Maggies) said that it was one of the 2 best systems he'd ever heard - and he'd listened to a number of $100K+ systems!
Sure, sometimes customers are not satisified. But if everyone else on the site raves about their AKSAs and you have a problem ... then possibly it was caused by your inadequate construction abilities, not the manufacturer?
Yet you don't appear to be able to accept this conclusion.
That is what is getting people het up, here.Regards,
Andy
Hello Professor smith
I've reply to all of your numerous MP's and I can say you again that it's very difficult to know what going on with your Aksa amp by only looking at photos or video, the method I've show you in one of my forum post was good, but the only way to know what are your Aksa problems is to have a close look at it, but you are in England and I am in Canada.
You don't have enough knowledges and understanding of diy electronics to do a kit, next time buy a ready made gear.
Bye
Gaetn
Hello Professor smith
All amps and preamps could be sensitive to mains noise, sometime the noise on the main can be very strong, here I have a neighbour who use very bad electrical tools and those tools are so noisy that TV become fuzy, but my amp do have a RF filter and Pi filter in the power supply and nothing get in my amp. But my ground and well made and my amp are dead silent.
Have you try a Pi filter in you Aksa power supply, like this one ?
Bye
Gaetan
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I've just read this thread, and I have to say prof smith has tested my patience!
either its someone taking the p**s or simply someone who has embarked on a journey with no possible destination.
put the AKSA on ebay and go buy a box from richer sounds............... god help them.
sorry,
but serious irritation factor going on.
either its someone taking the p**s or simply someone who has embarked on a journey with no possible destination.
put the AKSA on ebay and go buy a box from richer sounds............... god help them.
sorry,
but serious irritation factor going on.
Yeah, it's odd isn't it...... hundreds sold around the world, only one trenchant critic.
Very strange.... and I supplied it to him fully refurbished in module form, fully built, at a discount because they were used modules, returned good on trade.
It is naive, however, to expect to please everyone. The reputation of the AKSA made my company strong and established a reputation for musicality and reliability.
A lesson learned.....
Hugh
Very strange.... and I supplied it to him fully refurbished in module form, fully built, at a discount because they were used modules, returned good on trade.
It is naive, however, to expect to please everyone. The reputation of the AKSA made my company strong and established a reputation for musicality and reliability.
A lesson learned.....
Hugh
Just a question. I've had a chance to try different amps and speakers now since I got the AKSA. One thing which strikes me about the AKSA sound is that the upper frequencies are not refined. I remember being told the sound was grainless but I disagree here. Using two different speakers I get the same impression and furthermore using a different amp with both speakers I don't hear this grainy lack of clarity at the top end. Can you confirm my finding?
Actually, Prof, the top end was what drew many to the AKSA. This merely confirms my belief that you do not hear what others hear.
Why don't you tell the world what you paid for your fully built AKSA modules, and how much of a discount this was on the original kit? Then others would see how privileged you have been compared to other owners, and that your personal attacks on the amp quality represent something of a bitter vendetta.......
Hugh
Why don't you tell the world what you paid for your fully built AKSA modules, and how much of a discount this was on the original kit? Then others would see how privileged you have been compared to other owners, and that your personal attacks on the amp quality represent something of a bitter vendetta.......
Hugh
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