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Old 19th May 2009, 05:36 PM   #1
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Quote:
Originally posted by sparkle
well i have had Aksa 55 few months ago and I will put a small review a wrote for Hugh Dean (I hope he will be happy with it) related Aksa 55.
=====================

Well, my dear fellow friends..... in the past 6 months I was living with a nice little amplifier made by a good guy called Hugh Dean from Aspen Amplifiers. This text that I am writing is because I have had the need to write something positive about that little jewel in our diy comunity. This is because I have seen on this forum in some other forums that some guys try to accuse Mr. Dean of taking to much money for nothing out of our pockets・ Well, the one that has to pay always says that something he is buying is to expensive isn稚 it・ Unfortunatelly for them ・most of those guys didn稚 even listen to what they are trying to accuse.
Well, I hope that this small contribution will help to prevent such things to happen again.

Arround six months ago I started to build Aksa 55 N+ amplifier. The informations that I was provided with were more than enough to help me to build this nice kit. Also, if I have had some questions I was free to ask Mr. Dean to help me with them.
The quality of the pcb boards is very good. They are small but not to small ・just about right for the guys that want to have very compact looking amplifier ・in fact Mr. Dean has told me that he has invested (during his development time) arround 600 hours to develop the amplifier boards. Well, that is a lot of time ・the result is in my opinion very, very good. I did not feel that there is any not normal problems while soldering the boards. I even took the money and solder everything on the boards with WBT silver solder (well ・it can't make things worst). Also I have changed every electrolythic capacitor with Black Gate standard type capacitors I was having arround that were the same value as noted in schematic of the amp. I had the feeling that this might be better than use the capacitors provided in the kit. Resistors wer also changed to Dale RN55/60 resistors.... Well, Mr. Pass use them so I thought that they might be better to than the ones in the kit. Yes, yes, I know ・I have changed a lot in this kit ・but my opinion is that the change is only to a better not worst sound (I hope that I was not wrong).
Anyway, my current system at that time was Onix OA24 preamplifier, Onix SOAP 2 power supply for the amplifier and Onix OA601 power amplifier. The speakers were Rogers LS2a/2 studio monitors and I was having a nice diy dac and Pioneer transport. The system sounded good in my opinion but I wanted more of everything ・to develop further so to say.
I decided to take some notes so that I can examine the burning in process so when I first turned the amplifier on I noted no power on thump ・the amp was dead quiet like it is not working at all.. The sound was very fast and not sharp ・it was faster than my Onix power amplifier. Also the sound was with more air and with huge sounstage. I was very impressed and also happy with the result.
After that first turn on my nightmare with burning in started... Since I don't have to much confidense in myself I did not want to leave the amplifier turned on the whole night...Also I don't have to much time to listen to music during the day so I was playing the amplifier 2-4 hours per day. After I few days of taking notes of what was happening with the sound I decided to stop doing it because the sound was varying a great deal ・from simply astonishing to жorst than s..t・・sorry.... After arround 100-150 hours of listening and sometimes fighting with myself ・asking what was in my mind that i build this thing ・the amplifier started to settle down and take the final form.
The end result of everything ・my Onix is not playing any more (he is to be sold ), I have a tube preamplifier that I am working on right now based arround 12B4 tube (it is preety much in its final stage).... New speakers are also here, Fase Aria. Well, guys this little beauty oppened some new territories I did not hear at my home... The amplifier has a very big capacity ・it is VERY emotional amplifier very gentle but this doesn't mean that it doesn't have bass or something ・it knows how to make you FEEL the music ・this little beauty has taught me to listen to music not the system (even when I was listening on my old speakers and Onix preamplifier) ・I forgot to do that. Sometimes I am so satisfied with the feeling that I have in myself while listening to the music from Aria, Aksa, 12B4 combination that I don't want to move a muscle so that the feeling doesn't get scared and go away.... You know...

So I must ask You all, how much this feeling is worth to all of us..... Well, to me ・a lot ・I was looking for it for a long time... finally I found it ・and for the reasonable price too.

I must thank to Mr. Dean for his help and ideas ・he was allways having time to reply on my (sometimes stupid) questions. He was allways kind ・I did not feel at any time that he was angry on somebody or something ・was allways calm and helpfull. I want to thank him also for this amplifier that he has developed and no guys I don't have my wallet inside his company, I am telling this because I want to tell it; because I am happy and satisfied.
Best regards and happy diy
===========================================

can someone who has this amp help me?

I have the N+55 Version but the intial sound i heard has disappeared and even though its been on 24/7 for several days now, the bass has disappeared. The dynamics and transparency has gone. Nothing else in my systame has been changed.

I have been told that this is due to burn in of the black gate caps.

How does this process affect bass response?

Its almost as if the bass has been attenuated.

It has been powered on for about 2 weeks now. I would have thought burn in would be over by now?
 
Old 19th May 2009, 06:17 PM   #2
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Are you sure, Smith?

Did you read about this black electrolytic capacitor and its less good qualities
- it is not stable like a film or solid lytic caps -
BEFORE you experienced this change in sound?

Another tersting you can do ...
- if you have one new and dull black capacitor of exact same sort
- put in a simple 2-way switch
- flip randomly between old/new cap and listen

One thing is almost sure,
besides those black caps, there is not much in AKSA 55 N
or any other solid state transistors amplifier
that change over time + effects the electrical signal from output.

However, Loudspeakers having moving mechanical parts, surround gaskets from rubber,
may eventually change the mechnical quality of the woofer a bit.
This in turn gives a little, small possibilty to ACTUALLY hear things differently.

Will be very interesting to read Hugh Dean's explanation to your impressions.
He would have some educated thoughts, I am quite sure.

Regards
lineup
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Old 19th May 2009, 08:32 PM   #3
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Quote:
Are you sure, Smith?

Did you read about this black electrolytic capacitor and its less good qualities
- it is not stable like a film or solid lytic caps -
BEFORE you experienced this change in sound?
I dont understand what you mean by this?


Another tersting you can do ...
- if you have one new and dull black capacitor of exact same sort
- put in a simple 2-way switch
- flip randomly between old/new cap and listen

One thing is almost sure,
besides those black caps, there is not much in AKSA 55 N
or any other solid state transistors amplifier
that change over time + effects the electrical signal from output.

However, Loudspeakers having moving mechanical parts, surround gaskets from rubber,
may eventually change the mechnical quality of the woofer a bit.
This in turn gives a little, small possibilty to ACTUALLY hear things differently.

Will be very interesting to read Hugh Dean's explanation to your impressions.
He would have some educated thoughts, I am quite sure.

Regards
lineup [/B][/QUOTE]


Hugh has been telling me all along that it is a burning in of the black gate caps.
 
Old 19th May 2009, 08:52 PM   #4
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Quote:
Originally posted by Professor smith

I would have thought burn in would be over by now?
Not necessarily if they are BG standard. Getting constantly frustrated i don't think i will ever use those again. Hundreds of hours of break-in? By the time the BGs open up, half my system would need replacement. At least the tubes and cart. Rather put some Silmics or Gold Tunes and get ready to listen. May not be so crystal clear but at least there is bass.
 
Old 19th May 2009, 09:07 PM   #5
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Default ESR vs age

Besides the unavoidable change in output stage bias and X-over distortion as a class B amp thermally stabilizes ,a drastic change in sound should not happen. (like losing all the bass !)

All electrolytics have changes in ESR depending on temperature ,age ,and type. http://my.execpc.com/~endlr/esr.html

I have heard amps with the power supply caps near failure , this made for a noisy amp (hum), but the sound was not drastically affected. Bootstrap cap .. here the sound is affected (distorted)or the amp just fails. The DC cap at the feedback side of the differential would be the only one that could have such a drastic effect on bass as to eliminate it !

I have never used the blackgate's , they just mix carbon in the electrolytic "voodoo mix" , but I read that they become "stale" with age. I will stick to my 105C nichicon's , they "burn in" after
a day (hours) , and stay the same for the next 10 years.
OS
 
Old 19th May 2009, 09:10 PM   #6
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Default Mine ones burns when i put fire on them.


ahahahaha!

regards,

Carlos
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Power supply; ripple, filter, noise, stability and the use of capacitance multiplier... Portuguese and English; https://www.youtube.com/watch?v=sSm0ku1eIgg
 
Old 19th May 2009, 09:31 PM   #7
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But i am confused here. I am getting mixed messages.

So is it a burn in issue or not?

Carlos, you have the N+55 can you confirm whether the sound changes in the way I have described over the first 200 hours or so?
 
Old 19th May 2009, 09:54 PM   #8
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Anything short of a total failure of the cap or a misapplication of it should not have that drastic an effect on sound quality. Post a picture.

http://www.acoustic-dimension.com/blackgate/bgtech.htm

"A total of about 30 hours is the standard level. Once this process of idling is completed, the effect continues as long as the capacitor is kept at the same place and the operating environment does not undergo a substantial change."

Such as temperature? the music itself (bootstrap)? Now I am confused. wish I had one to see if it burns like a piece of coal - reverse polarity.
Ahhhh ha ha
OS
 
Old 19th May 2009, 10:00 PM   #9
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Default heehhehe


Sorry

I have never perceived those changes.

My amplifiers have never presented such kind of things

Check your speaker...maybe coil has melt.

I cannot say other folks delirates... but for sure i don't!

Also i do not use to drink, also i do not use strong medicine drugs too... maybe this explains why i cannot perceive those burns.... maybe i need some drugs to be normal...if "to be normal" is to listen/believe in such kind of capacitive miracle effects.

Once i have perceived something..but testing i could see capacitor was having leakage.

Carlos
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Power supply; ripple, filter, noise, stability and the use of capacitance multiplier... Portuguese and English; https://www.youtube.com/watch?v=sSm0ku1eIgg
 
Old 19th May 2009, 10:12 PM   #10
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Well, maybe there really is a good reason why many tube builders like the black gates

The "better"(?) black gate "models" are fore either very low voltage, or very high voltage

I must admit that every time that I hear that a certain cap does something exstraordinary to the sound, I only just get suspicious
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