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Old 15th June 2010, 03:59 AM   #11
AKSA is offline AKSA  Australia
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Jay,

Apa kabar? Anda berasal dari Indonesia, atau negeri barat, mungkin AS? Saya di JKT Jan 2009, berkunjung keluarga istri di SMG.

You are essentially correct, there are some issues not covered. A quick email to Greg will clear most of them up, however. I do not wish to put this valuable circuit in full detail on a public forum, because I know some considerate fellow will start to make them in quantity, and since it's my IP I feel I should make it tough for him.

I agree with NP. A good amp is one third topology, one third layout, and one third parts choice. When it's all weighed up the topology is only a small part of it.

Cheers,

Hugh
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Old 15th June 2010, 05:19 AM   #12
Jay is offline Jay  Indonesia
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Jay,

Apa kabar? Anda berasal dari Indonesia, atau negeri barat, mungkin AS? Saya di JKT Jan 2009, berkunjung keluarga istri di SMG.

You are essentially correct, there are some issues not covered. A quick email to Greg will clear most of them up, however. I do not wish to put this valuable circuit in full detail on a public forum, because I know some considerate fellow will start to make them in quantity, and since it's my IP I feel I should make it tough for him.
Hi Hugh, I'm from Jakarta

I posted on this thread because I was surprise about Aksa55 being not in production anymore and the (what I thought was Greg's) following statements regarding the possibility to expose those which was not possible before.

I tried to re-read the original post but I couldn't find the statement, so okay may be it's my hallucination

Just after I posted my comment, it came to my thinking that it is of course impossible that Greg doesn't know your circuit. And I thought I knew what is going on and I will shut up.

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I agree with NP. A good amp is one third topology, one third layout, and one third parts choice. When it's all weighed up the topology is only a small part of it.
Yes, I think you and NP are alike in term of empirical expertise. Parts choice is indeed important especially with mosfets. And it was a surprise to me that it takes so long for NP to come up with Aleph J (It seems impossible that he just needed to get rid a ton of his IRF9610 in his warehouse). That's why I think I need to start studying to design my own amp. Because it is impossible to wait for him to design amplifier that I already "have" in my mind.
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Old 15th June 2010, 05:45 AM   #13
Luke is offline Luke  New Zealand
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Quote:
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I agree with NP. A good amp is one third topology, one third layout, and one third parts choice. When it's all weighed up the topology is only a small part of it.
Hugh,

are the thirds equal in your opinion, I would have guessed 60/20/20?
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Old 15th June 2010, 06:46 AM   #14
Mooly is offline Mooly  United Kingdom
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I'm surprised at that tbh

Topology is everything when it comes to sonics... layout and wiring is of absolute utmost importance... and parts ? well IMO as long as they are good quality commercial grade then that's the least important factor. Choose good parts for long life/performance, but I would never pay for "boutique" stuff.
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Old 15th June 2010, 06:48 AM   #15
rabbitz is offline rabbitz  Australia
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Greg is also the owner of Hugh's AKSA 55 and had upgraded to the 55N+ so will have Hugh's original design to compare the Baby AKSA.

I'd be very surprised if it doesn't have a similar presentation to Hugh's commercial AKSA.

I haven't built the Baby AKSA but have built several of Hugh's and have found the cap used at C4 can have a significant bearing on the final sound. I had best results with a Nichicon KZ (100uF 50V) in that location.... hint don't use a BG standard. Nichicon FG worked well for the other electrolytics but I don't think would be better than any other good quality cap of similar quality.
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Old 15th June 2010, 07:43 AM   #16
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Greg is also the owner of Hugh's AKSA 55 and had upgraded to the 55N+ so will have Hugh's original design to compare the Baby AKSA.

I'd be very surprised if it doesn't have a similar presentation to Hugh's commercial AKSA.
Yes I do have an AKSA or two. I've also got a DIGI 125 that is similar. I am familiar with circuits and component values and I know rabbitz's mods as well.

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I haven't built the Baby AKSA but have built several of Hugh's and have found the cap used at C4 can have a significant bearing on the final sound. I had best results with a Nichicon KZ (100uF 50V) in that location.... hint don't use a BG standard. Nichicon FG worked well for the other electrolytics but I don't think would be better than any other good quality cap of similar quality.
I was definitely going to bring this up in a week or two. A Nichicon KZ in C4 is a very good recommendation, 95 cents well spent. BTW, the 100uF Nichicon KZ (50V) and FG (63V) are the same price. Peter, would the KZ's work as well as the FG's in the non-bootstrap locations. I would work out a little cheaper for quantity discounts if I got one type.

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Old 15th June 2010, 07:49 AM   #17
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I'm surprised at that tbh

Topology is everything when it comes to sonics... layout and wiring is of absolute utmost importance... and parts ? well IMO as long as they are good quality commercial grade then that's the least important factor. Choose good parts for long life/performance, but I would never pay for "boutique" stuff.
Hi Mooly,

I have a foot in each camp. I have personally experienced the differences a few components can make to simple circuit like this, but I also have friends with more politically correct amps using almost generic parts that sound wonderful as well. It might be the ear of the designer/tuner that is most important.

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Old 15th June 2010, 08:31 AM   #18
AKSA is offline AKSA  Australia
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Mooly, Luke

This is a subjective judgement.... and you can't be objective about it. It's just opinion, and should be taken with a crystal of chloride of sodium.

I prefaced my assessment with my agreement with NP, hoping it would make a cast iron point, but then, I'm not NP, am I? No one argues with him, to my great pleasure I might add. He has a proven track record after all.....

Hugh
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Old 15th June 2010, 12:33 PM   #19
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Quote:
Originally Posted by Mooly View Post
Choose good parts for long life/performance, but never pay for "boutique" stuff.
If i were to design a +50kn high speed vessel i'd have to choose the hull type (topology), the type of propulsion and materials used (parts), and tweak the hull geometry with model tank testing (layout).
Each of those components has an equal share in the final outcome.
Even the best commercial grade steel is useless compared to sealium alloy or carbon/aramid fiber composites.
Even the lowest kg/kW modern diesel engine is inferior compared to a 0.2kg/kW Vericor marine gas turbine.
Next parts step, above 30 knots speed nothing outperforms efficiency numbers of water jet propulsion systems.
The chosen hull topology often inherently determines the choice of parts.

Picking good quality general commercial parts may get you to the finish line more cost efficiently, but you will not have pole position and not finish first either.
Dismissing any part that is not generic commercial grade by labelling it as "boutique" is the equivalent to deciding not to compete for the design performance target from the onset.
About as pointless as the opposite approach : hoping to finish 1st with unsubstantiated, no one does voodoo like you do, boutique parlor items solely.
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Old 15th June 2010, 01:06 PM   #20
Bigun is online now Bigun  Canada
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I've built my 'clone' of AKSA with the TGM1 amp and I can testify to the importance of part choices and the subtle but important effect of optimizing the values of the compensation components.

I haven't tried different layouts & wiring, but it doesn't take much effort to see the impact of parasitic capacitance and inductance using Spice. It's certainly important.

And don't forget the power supply, another essential element of the amplifier.

Anyhow, I hope everyone will respect Hugh's wishes to keep the details of his AKSA out of the public eye.
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