Valhalla - AKSA 55

cmscott6 · « **Reply #40 on:** 1 Aug 2003, 12:50 am »

Sorry. In my original post I did mean to type Black Gate "FK" not "FG". I'm still not sure that I understand the difference between the standard and FK series.

After the caps have had a chance to "break in" everything still sounds wonderful; the difference in detail still really impresses me. I'll be curious to hear if others have the same reactions.

PSP · « **Reply #41 on:** 5 Aug 2003, 07:11 pm »

Has anyone tried simply bypassing the AKSA PS caps, say something like 4700uf (stock cap) bypassed with (470uf Panasonic or Nichicon + 47uf Black Gate + 4.7uf Black Gate or Axon)? If not, I'll put it on my "to do" list...

Peter

andyr · « **Reply #42 on:** 5 Aug 2003, 09:42 pm »

Peter,

Yes, there was a thread about this a while back. Hugh commented that one of his mates recommended using a 47uF Solen (or better) to bypass each rail.

Regards,

Andy

TimS · « **Reply #43 on:** 19 Aug 2003, 03:13 pm »

Quote from: AKSA

Hi Peter, Sam,

My thanks for your advice, Peter. Appreciated.

Sam wrote:

Sam, there are four caps on each side, rather than three, and yes, each has its own + and - polarity.

Each bleeder resistor - there will be four - must be connected between the two rails and ground of each channel. So, on the left channel, connect a 15K resistor to ground from both the positive rail and the negative rail. Both resistors will meet at star earth, of course.

The caps are indeed being bled constantly. Ho ...

I've found an alternative to the bleeder resistors which uses the unused contacts of the DPDT on/off power switch to discharge capacitors. -See

http://www.e-insite.net/ednmag/index.asp?layout=article&articleId=CA90760&stt=001

Tim

The Oracle · « **Reply #44 on:** 19 Aug 2003, 06:48 pm »

Could anyone please tell me if a 50v BG (FK model) could be used in position C3 -- SAFELY!
This is much narrower than the 100v model (and cheaper)
I'm not sure of the volt drop across R10
Relates to 100 watt AKSA
Thanks guys

The Oracle

stvnharr · « **Reply #45 on:** 20 Aug 2003, 01:31 am »

Am presently listening to my AKSA 55 Twins with 50v BG std's in C3.
Sound is to die for!!!!!!!!!!!!!!!
It has also cured me of tube-itis in power amps.

AKSA · « **Reply #46 on:** 20 Aug 2003, 02:18 am »

Quote from: The Oracle

Could anyone please tell me if a 50v BG (FK model) could be used in position C3 -- SAFELY!
This is much narrower than the 100v model (and cheaper)
I'm not sure of the volt drop across R10
Relates to 100 watt AKSA
Thanks guys

The Oracle

Hi Steven,

Yes, no problem. However, any fault condition in the amp will destroy this cap; so be warned. In normal operation it will have around 25 volts across it, which is fine.

Cheers,

Hugh

stvnharr · « **Reply #47 on:** 20 Aug 2003, 05:26 am »

Okay. 50v is twice the spec, but then how much is best in a worse case scenario? There are several choices in the BG family.
Can one ever feel safe that "a fault" will not happen?

The Oracle · « **Reply #48 on:** 20 Aug 2003, 06:20 am »

This is 100WATT MODEL remember? (yes I know I'm in the wrong thread)
50v is okay except when the big meltdown happens on 18th November?
If a fault happened, wouldn't one be turning the amp off after several seconds? so 49-52volts (rail) surely wouldn't stress a 50v cap? or are they that delicate! and am I missing something.
As always - I'll do what's logically recomended

P.S. Hugh's blown my cover - I'll have to pull the trigger now.

the Oracle

Malcolm Fear · « **Reply #49 on:** 20 Aug 2003, 09:42 am »

I recollect reading somewhere, that you need to run Black Gates at about 80%.
So, if you buy 50 volt, and they are running at 40 volts, then this sounds better than buying 200 volts and running them at 40 volts.

SamL · « **Reply #50 on:** 22 Aug 2003, 10:05 am »

What about C4 on aksa100, is it worth switching to BG?

SamL · « **Reply #51 on:** 22 Aug 2003, 08:46 pm »

Quote from: AKSA

I am presently auditioning Black Gates in my 55W Nirvana. All four 100uF caps on each module have been replaced - thank you Phillip! - and while at first I felt it was grainy and metallic, this is now improving by the hour. The final take I'll give in a week or so, but it's pretty bloody good right now, I can tell you.

Found the above on another post. I guess the AKSA100n would be the same.
With 8 caps to change, will go for the BG standard. The challange now is find a way to mount them.

Sam

cmscott6 · « **Reply #52 on:** 22 Aug 2003, 11:29 pm »

I swapped out my power supply caps on my 55N: from the Chemicon to Nichicon FG's (same values). It's something I've wanted to do for a while, as I had great experiences with these as PS caps on a pre-amp.

After about 10 hours of run time there is a noticeable difference on the bass: it's much fuller, and lower register notes, especially on acoustic bass, are much clearer and distinct. I'm not sure that I hear any difference on the mid's and high's - which is OK, as they sound wonderful with the Black Gate upgrades (and GK-1 with Auricaps). One of my best listening experiences came two nights ago with these new caps - on a classical radio FM broadcast of all things. It was a modern recording of an orchestral piece by Edgar Meyer, and as I listened I could pretty much close my eyes and point to every instrument in the orchestra from tympani - higher and back in the middle/left- to piccolo front center. The bowed double bass lines were phenomenal. Weird to get such detail and imaging from a radio station...

Malcolm Fear · « **Reply #53 on:** 23 Aug 2003, 04:16 am »

Where did you purchas the Nichicons?

andyr · « **Reply #54 on:** 23 Aug 2003, 07:37 am »

Quote from: cmscott6

I swapped out my power supply caps on my 55N: from the Chemicon to Nichicon FG's (same values). It's something I've wanted to do for a while, as I had great experiences with these as PS caps on a pre-amp....

Can you explain why U used Nichicon FGs and not KGs? I thought KGs were the better ones?

Regards,

Andy

cmscott6 · « **Reply #55 on:** 23 Aug 2003, 02:25 pm »

Sorry folks. Once again I'm confusing my Black Gate and Nichicon nomenclature

. For the power supply caps I used 4700uF 63V Nichicon KG (Gold Tune). The pin spacing fits perfectly on the pcb, and though the caps themselves are a little more squat, all four still fit nicely. I also put four bleeder resistors on the pcb.
I purchased the caps from Michael Percy (www.percyaudio.com). He has a pretty broad selection of Nichicon, reasonable prices, and quick service. There is also the "Super Through" series, which is (according to Nichicon) a higher grade, but the values start at 10,000uF, and the diameter would necessitate off-board mounting. Didn't Hugh also mention that higher values of capacitance in the ps would perceptibly "slow" the sound of the amp as well? Anyone have an opinion/experience with that?
I guess my next tweak is the Riken Ohm resistor on the way from Parts Connexion... (Addiction? I can quit whenever I want

)

The Oracle · « **Reply #56 on:** 23 Aug 2003, 09:53 pm »

Sam
This relates to 100watt
I got caps with the same dimensions as the Black Gate models and played around.
I chose all Standards except for C3 (FK? - it was labelled as K on Partsconnexion list, but could be a typo)
C11/13 reduced to 47uF/100v - same size as supplied
C3 - 100uF/50v
C4 - 100uF/50v
C2 &7 - 10uF/50v
Only C2,4 &7 are a little tight - but wont be a problem.
I wanted to keep the values the same (except C11/13) after reading Hugh's FAQ's again - I'm after bullet proof reliability. After all - would'nt want to blow all the drivers on the Wilson Audio Grand Slam

The Oracle

SamL · « **Reply #57 on:** 24 Aug 2003, 12:20 am »

Quote from: The Oracle

Sam
This relates to 100watt
I got caps with the same dimensions as the Black Gate models and played around.
I chose all Standards except for C3 (FK? - it was labelled as K on Partsconnexion list, but could be a typo)
C11/13 reduced to 47uF/100v - same size as supplied
C3 - 100uF/50v
C4 - 100uF/50v
C2 &7 - 10uF/50v
Only C2,4 &7 are a little tight - but wont be a problem.
I wanted to keep the values the same (except C11/13) after reading Hugh's FAQ's again - I'm after bullet proof reliability. After ...

Hi Oracle,
Thanks for the info.

I've the AKSA100N so will not change the C2 and C7.
Well, below is the my current wish list.
- BG std on C3, C4,C11 & C13.
- Replace Aksa 100 power caps with same value Nichicon caps.
- Bypass power supply caps with 47uf BG caps.
- Replace R22, R20, R21 and R23 with Millis resistors. I've used Mills resistors in speaker crossover and they are better then the sand cast resistor in high frequency application. It takes away the matalic sound from electroic instrument. Anyone used this in AKSA?
- Vampire binding posts.
- Cardas female RCAs.
- Cardas 10.5ga chassis wire for power and speaker connection inside AKSA.

Due to limited funding approved by my finance manager (wife), I have to strike one or two off my wish list.

Can someone help & tell me which are the most worth while sound investment.

Thanks,
Sam

stvnharr · « **Reply #58 on:** 24 Aug 2003, 06:01 am »

Sam,
If you want something small to strike something off the wish list, strike the 10ga Cardas wire. The wire likely doesn't need to be such a big gauge, and unless you are familiar with Cardas wire and have a solder pot, you will find it very difficult to work with. In order to get a good solder joint you have to get the enamel off ALL the many many strands of wire. I've used 15.5 ga quite a bit and it's a real pain. Best way to get the enamel off without a solder pot is to use a lighter and then sandpaper off the black residue to get bright wire. Even then it still takes a lot of heat to get the solder to stick.
OTHO, Cardas GFRA rca's are really great. Keep them on the list.

Malcolm Fear · « **Reply #59 on:** 25 Aug 2003, 12:36 pm »

AKSA 55 mods.
I replaced all electros on the amp boards with Black Gates.
I replaced resistors in the signal path with Riken Ohms.
I did it bit by bit.
Black Gates do great things to the bass.
Riken Ohms do great things to the smoothness.
Together they do great things to an already great amp.
The whole experience is just more involving. I've gone back through my Dylan, Counting Crows, Eva Cassidy, Leonard Cohen, Robbie Robertson, Neil Young, Diana Krall, Warren Zevon etc. It is great.

I wonder if we can use the ideas from AA - cables - Jon Risch, and get circuit boards made of teflon, with tracks made of pure copper?
I wonder if there is software that will design boards with gentle curves not sharp bends (a la Metaxis)?