Of course you don't need 600V: in fact if you read the initial paper from Papa you will find that 25V rating is enough to do the job on all 3 positions...
The 600V just came with the caps I went for, but I couldn't care less about that spec TBH
As for the 3rd caps, I will leave the expert reply... perhaps if you have already a DC blocking cap at the entry of the power amp, you can do without? That's what I did in my ref system, but the B1 KORG is so special regarding DC that I will let the ususal knowledgeable suspect reply
Have fun
Claude
The 600V just came with the caps I went for, but I couldn't care less about that spec TBH
As for the 3rd caps, I will leave the expert reply... perhaps if you have already a DC blocking cap at the entry of the power amp, you can do without? That's what I did in my ref system, but the B1 KORG is so special regarding DC that I will let the ususal knowledgeable suspect reply
Have fun
Claude
Reading ZM's post to me again on caps, I realise he mentioned 12V DC at the output of the last stage before the 3rd cap... hmm, not sure you can do without 3rd cap eventhough you have a DC blocking cap in the power amp, some little current would then flow to mass through the 33.2k resistor, but no clue if a real prob or not
For sure ZM & Co can confirm or infirm, as interesting point about the most expensive cap to replace, the one that raises the most questions...
For sure ZM & Co can confirm or infirm, as interesting point about the most expensive cap to replace, the one that raises the most questions...
That is exactly what I want to accomplish! It looks great.
Could you tell me what Chassis that is and where to source it please?
it's a 2U galaxy w / steel 330x170mm covers with a 3mm front panel.
it is on sale on diyaudio store.
Thank you Claude for these indications.
I'm waiting for the details of Zen Mod for the 3rd signal path.
A+
Christophe
Thanks! Just ordered it as the last piece on my build. I was attempting to wait until the custom one was available, but again, my impatience won out over my laziness. I have a very capable drill press and a friend that owns an engraving shop. Just more DIYing. 😉
Hmm, no reply concenrning that 3rd cap... perhaps all on holidays or indeed not that easy to answer?
Sorry, I can't help further myself on that one... my guess (and comments) is/are as good as yours
Claude
Sorry, I can't help further myself on that one... my guess (and comments) is/are as good as yours
Claude
No worries,
I have the time, especially since it is very hot in France even in Brittany (106 ° F today).
A+
Christophe
I have the time, especially since it is very hot in France even in Brittany (106 ° F today).
A+
Christophe
Not good practice to have ~12VDC at the output of your pre-mp. Your choice to eliminate the cap, but someday, someone (maybe you) will plug it into a DC coupled amp and possibly blow up your amp and/or your speakers!
Well, as said I didn't, I went for a 3.3uF quality cap in that 3rd position... exactly for the reasons you stated.
But as some raised the question, it made sense to have your confirmation on what was doable and with what trade offs...
Thanks for the reply
Claude
But as some raised the question, it made sense to have your confirmation on what was doable and with what trade offs...
Thanks for the reply
Claude
BTW Claude how is your final verdict with all 3 pairs of elcos replaced? I'm sorry if you commented already and I missed...
Verdict: as far as I am concerned MUST DO. Each cap replacement brought another plus.
That mod does the Korg justice, it deserves the best (don't be biased by its low price) and is IMHO from all tweaks the one to address first - kind of small bottleneck.
Once you replace all caps in the signal path, it moves into another class (given the standard version is already very good) - wether you need it really or not is of course up to you - for me it is a no brainer as I wanted the max from it, eventhough a little bit of fiddling is required. If I would build another one, I would plan it from the start, easier and cheaper, together with somewhat bigger PS caps.
The overall quality is now that good that I doubt that many more can be expected or achieved in absolute terms, nor that the 3 (quality) caps in the signal path are still really affecting the sound vs no cap - if such an option would exist (but it doesn't of course).
Very very nice little preamp again, and IMHO a giant killer in absolute terms... plus with the possibiliy to be adjusted re 2nd harmonic level as you wish, plus of course that very nice and nearly unique ability to move from positive to negative H2 (I love negative H2).
As the B1 Korg can be adjusted as you want (and I encourage you to play with that), it is very likely to suit you regardless the quality level you seek - unless of course if you like a very direct and very "dry" sound (or you have alreay other components bringing these H2 tricks). So my sole recommandation would be not to overdo it too much with that H2 distorsion level, but that's me. At the end, I found that Papa's recommendations were (of course...) a very good starting point and I ended close to it (0.3V variation). I ended up with something that must be half the recommended distorsion level, that suits me more, but whereas it sounds like a lot less... it is just a few dB less distorsion, so still quite close.
Enjoy it very much
Claude (who for decades didn't want to hear about active preamps as found useless, ahem...)
That mod does the Korg justice, it deserves the best (don't be biased by its low price) and is IMHO from all tweaks the one to address first - kind of small bottleneck.
Once you replace all caps in the signal path, it moves into another class (given the standard version is already very good) - wether you need it really or not is of course up to you - for me it is a no brainer as I wanted the max from it, eventhough a little bit of fiddling is required. If I would build another one, I would plan it from the start, easier and cheaper, together with somewhat bigger PS caps.
The overall quality is now that good that I doubt that many more can be expected or achieved in absolute terms, nor that the 3 (quality) caps in the signal path are still really affecting the sound vs no cap - if such an option would exist (but it doesn't of course).
Very very nice little preamp again, and IMHO a giant killer in absolute terms... plus with the possibiliy to be adjusted re 2nd harmonic level as you wish, plus of course that very nice and nearly unique ability to move from positive to negative H2 (I love negative H2).
As the B1 Korg can be adjusted as you want (and I encourage you to play with that), it is very likely to suit you regardless the quality level you seek - unless of course if you like a very direct and very "dry" sound (or you have alreay other components bringing these H2 tricks). So my sole recommandation would be not to overdo it too much with that H2 distorsion level, but that's me. At the end, I found that Papa's recommendations were (of course...) a very good starting point and I ended close to it (0.3V variation). I ended up with something that must be half the recommended distorsion level, that suits me more, but whereas it sounds like a lot less... it is just a few dB less distorsion, so still quite close.
Enjoy it very much
Claude (who for decades didn't want to hear about active preamps as found useless, ahem...)
Thanks Claude!!! This is something I was expecting based on my previous experience with elcos in signal path. I will definitely do the caps replacement and put it with LDR attenuator. I liked what I heard in my test setup even with really crappy pot... Only noticable downside was lack of transparency which is I believe firstly on pot and second to elcos.
FYI Just got a heads-up from Jason that the Universal PS boards are in stock. I ordered two since I have a feeling the F5 isn't likely to be my last requirement for them. 😎
Thanks Bassivus
This unit doesn't lack transparency, in fact it is magnifying things a bit (and nois thresold is very low) so with the right parts no doubt you will get where you want!
Have fun
Claude
This unit doesn't lack transparency, in fact it is magnifying things a bit (and nois thresold is very low) so with the right parts no doubt you will get where you want!
Have fun
Claude
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Claude - thank you for the detailed update! I just ordered a set of caps from Mouser last night, so I'll tackle the swap when they arrive.
I also picked up a set of these rubber shock absorber mounts for under the Korg board to see if they help better insulate the Korg tube from vibration: M3 Rubber Shock Absorber Damping Anti-Vibration Holder for F3 F4 Kiss FC M2Y5 | eBay
Because mount all of my boards with M3 hardware, it's a simple swap for rubber mounts. I'll do both changes at the same time when things arrive next week.
I also picked up a set of these rubber shock absorber mounts for under the Korg board to see if they help better insulate the Korg tube from vibration: M3 Rubber Shock Absorber Damping Anti-Vibration Holder for F3 F4 Kiss FC M2Y5 | eBay
Because mount all of my boards with M3 hardware, it's a simple swap for rubber mounts. I'll do both changes at the same time when things arrive next week.
Hi ClaudeG,
I’ve always had fine results using Elna Silmics and wasn’t going to change them out of the signal path of my B1 Korg. But, following your in depth and very thoughtful capacitor swapping results I became very curious. I had a bunch of Wima 2.2uF polycarbonate film caps that needed a home, so out went the Elna’s and in went the Wima’s.
It’s only been a couple of days since the swap but there is an improvement. The frequency extremes seem unchanged, it’s the overall presentation of music that’s improved. It’s subtle, but the soundstage has opened up.
I will agree with you, this mod is worthwhile 🙂
Thanks for sharing your thoughts!!
Eric,
Those M3 damping stand offs are perfect!
Thanks for posting the link.
Best,
Vunce