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Modify your Woo 6. . Sophia and EML 274B . Images pages 32, 33, 34 of int. and ext. and...

post #1 of 893
Thread Starter 
While I don't expect this thread to get a great deal of response due to the smaller number of 6's out there in relation to other amps, this amp is well worth working with.

The only change I have made so far is to swap out the cathode caps to Black Gate nonpolar 16 volt 470uf (red). The change was larger than I had expected. I have used many types of caps and batteries for bias but this one simple change was the most noticeable I have heard. Why I don't know for sure but I did go from a medium quality cap to a very high one and I changed the capacitance from 220 to 470uf. I have always found 470 to be a standard for cathode bias along with the cathode bias resistor.

Transparency improved along with a noticeable increase in stage width and depth. Bass took on a strong controlled quality and mids, the one area I really wanted to see an improvement, took their correct place on stage. Voices of men and women improved and are very realistic.

****

June 8,

The further modifications can be found in the threads of this post:
A pseudo dual power supply was added with nonpolar Black Gate capacitors
Kiwame resistors are used
and the power supply is a CR(divided for the dual supply)CRC for the power section of the tube and RCR for the driver section. All capacitors are Black Gate
The coupling capacitor is the silver/gold oil .22 capacitor.


edit:
The relative speed of the amp also has increased. There is no smearing of the frequencies with a clean contrast between notes and the rest of the musical spectrum. I am still surprised after many years of working with cathode bypassing that this one small change has made this big of a change. The slight veil that was present is gone.
post #2 of 893
let's see some pics jamato!

i like the way you're taking on this upgrade. one part at a time will
give better insight as to how significant each upgrade contributes
to the overall sound...if you have the curiosity, please try out a
gz30 gt-style mullard...it's my favourite rectifier for the maxed wa6...
best neutrality, transparency and accurate tone of acoustic instruments...
post #3 of 893
Jamato, it took you longer than I expected to crack open your Woo6
post #4 of 893
This kind of thread is bad news for my wallet. First was that other thread, now this one...makes me want to swap some caps out. Only problem I have is I know nothing. I just want to take what I'm hearing with the WA6 at the moment to another level. Been searching for a reputable shop locally to do the work for me, and there's one in my city. So TIA for any questions I'll ask when I'm ready to take the leap.
post #5 of 893
Thread Starter 
Quote:
Originally Posted by HiGHFLYiN9 View Post
Jamato, it took you longer than I expected to crack open your Woo6
Last year was a very difficult and strange one. I got back from China last January and things never went very smooth. Hopefully things will allow for more time to do some mods etc.

I have to add that I stress, these cathode caps are important but not just any cap.
post #6 of 893
Thread Starter 
Quote:
Originally Posted by JZImages View Post
This kind of thread is bad news for my wallet. First was that other thread, now this one...makes me want to swap some caps out. Only problem I have is I know nothing. I just want to take what I'm hearing with the WA6 at the moment to another level. Been searching for a reputable shop locally to do the work for me, and there's one in my city. So TIA for any questions I'll ask when I'm ready to take the leap.
I wasn't totally happy with the sound. I can tell that this amp can be jump started to a much higher level than I suspected.

I am going to install not one extra power supply cap but 2 and maybe three. I am going to divide the power to the output tubes, which is a major upgrade.
post #7 of 893
Thread Starter 
Quote:
Originally Posted by takezo View Post
let's see some pics jamato!

i like the way you're taking on this upgrade. one part at a time will
give better insight as to how significant each upgrade contributes
to the overall sound...if you have the curiosity, please try out a
gz30 gt-style mullard...it's my favourite rectifier for the maxed wa6...
best neutrality, transparency and accurate tone of acoustic instruments...
I don't have any of the GZ30 types. I have some varieties of GZ34's (two different metal base) and some others.
post #8 of 893
Jamato:

I hope this wouldn't be too much to ask but would you consider a pictorial guide to the mods you're performing? You'd probably get bored because the pics wouldn't have quite the style and flare that the ones in your gallery do (really like some of your stuff by the way), but it would really help us newbies as we consider cracking open our WA6's and embarking on the journey that is DIY mods.

You and Takezo seem to know A LOT about this amp and I'm sure there are more than just myself that would really appreciate some guidance on this thing.

Thanks!
post #9 of 893
I would also be very interested in seeing some pics!
post #10 of 893
Thread Starter 
There is plenty of room to use even stock caps to divide the power supply for each power section of the tube. This is not very expensive and would be an upgrade that Woo Audio would have an easy time of. Right now the two tubes run off of the same cap, which in my opinion, compromises the sound. Such an easy fix.
post #11 of 893
I'll follow suite as well in requesting some pictures of your mod. jamato8 ("stock caps to divide the power supply for each power section of the tube"). Could you list the caps used for this? Thanks, K.
post #12 of 893
Thread Starter 
Well I divided the power supply to the output side of the 6DE7 so that each half has it own supply. I also doubled each cap for the output, which doubles the capacitance of course but also reduces the ESR. I used the stock caps as I have not gone to Black Gates yet. I would like to hear what it is like with stock caps anyway and with some of these modifications which do not cost very much. Now to let it settle in.

Oh, those who like solid profound bass, well this has it.
post #13 of 893
nice, looking forward to your impressions on the power supply mod.

btw, will this config. work too? i'm thinking of implementing two separate
CRC routes from the rectifier to the output tubes. space will not be an
issue from what i can see...

rectifier- cap1 - (1000ohm R)- cap2- output 6de7 left

""""""""""- cap3 - (1000ohm R)- cap4- output 6de7 right
post #14 of 893
Thread Starter 
Sure but cap 1 and 3 are just paralleled so you double capacitance but nothing more. If you wanted to have more separation you could go to rectifier, CR(split after first R) CRC but I am not sure you would gain much.
post #15 of 893
i figured starting the parallel run from the rectifier would be better
than after the first power filter cap, but i see what you mean...so,
you'd suggest i run two resistors off the first power filter cap after
the rectifier? thanks
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