Output Capacitor Upgrading Questions

[Adrian]

Like properlydeafened I have replaced the Crack output caps with Mundorf MKP 100uF caps and this post will be somewhat redundant.
I burned-in these caps using a Gainclone amp for a full 8 days (about 200 hours) before putting them in.

I very much like what these have done to my HD600s.  If there is the "Senn Veil" (and there is), then these caps have lifted it and I have discovered a deeper, more prominent bass and cymbals that sound like cymbals.  Brushes on the drum head, the wood of the doublebass, and the breath of the trumpet are right.

I'm glad I did this.
Here are a couple of pics (I did this late at night and put a burn mark on the left channel!)

 

[Tom-s]

Bypassing the standard electrolytics costs about 1/10th of the price of film caps.
Would just bypassing do anything positive for the sound? Using Russian K75-10 and/or FT-3 caps.

 

[JamieMcC]

Bypassing the standard electrolytics costs about 1/10th of the price of film caps.
Would just bypassing do anything positive for the sound? Using Russian K75-10 and/or FT-3 caps.

The caps you mention only cost about the same as a fancy cup of coffee. I have used them as bypasses for films and found they made a very noticeable difference but have not tried them as bypasses to the stock electrolytic caps.  If you a are patient 100uf films often turn up on ebay old stock or used etc for a fraction of their cost new. 

 

[Tom-s]

Thanks for the reply.
I see you've done a bit of cap rolling yourself.
What is your preferred cap combination? How do the Russians compare to other bypass caps?

 

[JamieMcC]

Thanks for the reply.
I see you've done a bit of cap rolling yourself.
What is your preferred cap combination? How do the Russians compare to other bypass caps?

The Russians worked well but its a subjective subject and not all combinations are going to work so it is very much a case of trial and error.

I have a couple of favourite cap combinations which are not *audio caps*. On of my favourite combos are these mgbo pio with Teflon bypasses (thanks Geary for the inspiration) total cost was about £20 I found them preferable to a pair of Mundorfs which cost £80 a pair!

Something to think about is that the teflons take simply ages to burn in before revelling their true nature  200-500hrs is not uncommon.

With the Russian caps getting them to fit in the Crack is a challenge. If you don't want to experiment have the budget then get the Mundorf MKP these are a cut above the likes of budget Solen, JFX, Dayton, (I have tried them) but  if you add a Teflon bypass to the budget caps it can bring them much closer to or even preferable to the Mundorfs. 

Most of these have been tried in the Crack at one time or another.

 

[Tom-s]

Thanks for the reply! As a student money is limited (Crack is great for the price!).
For now i left the space for Ansar caps (supposed to be good caps). This includes one 220uf for the PS.
These will fit nicely with the CLCLC setup in there now.
The price of these with Russian PIO/teflon bypass will be +- £150 (output + PS).
Building a new case for the Russian MBGO-2's will be a challenge but at a total of £50 it fits my budget.

Edit: Forgot the PS is 250V. The MBGO's are only 160V. So i'd need another for the PS.

 

[mcandmar]

Best bang for your buck are Solen MKP @ $29 each from partsconnexion.  Or if your in Europe the JB JFX series or Mundorf MCap @ £29 each from hificollective. All of which are available with a 250v rating so you will have no issues fitting them into a stock enclosure.

 

[Tom-s]

Ansar 100uf/160v L=57mm*D=49mm. Price is comparable to the Mundorf Mcap Evo 100uf.
220uf/250V PS cap L=87mm*D=60mm for about £50.
That's why those are my first choice. They fit the enclosure easily and leave enough room (but not the budget) for Russian bypass caps.

 

[mcandmar]

In that case might i suggest buying Solen caps directly from http://solen.ca/product-category/capacitors/fast-capacitors-250v-pa-series-metallized-polypropylene/. Two 100uf and one 220uf 250v cap works out at $190 inc shipping, which is £95.

 

[Tom-s]

That's sure cheap but i'm in Europe. So American caps would add +30-50% for tax and customs.

 

[Tom-s]

The operating voltage of the MBGO-2 caps is 160v.
Would it be a problem using these as the last PS cap?

 

[JamieMcC]

Thanks for the reply! As a student money is limited (Crack is great for the price!).
For now i left the space for Ansar caps (supposed to be good caps). This includes one 220uf for the PS.
These will fit nicely with the CLCLC setup in there now.
The price of these with Russian PIO/teflon bypass will be +- £150 (output + PS).
Building a new case for the Russian MBGO-2's will be a challenge but at a total of £50 it fits my budget.

Edit: Forgot the PS is 250V. The MBGO's are only 160V. So i'd need another for the PS.

This is how Geary fitted the mbgo capacitors in his Crack in the output position its one of my favourites as well

The operating voltage of the MBGO-2 caps is 160v.
Would it be a problem using these as the last PS cap?

Yes you want to stick with a voltage equal to or greater  than the capacitors you are replacing take a look at the choke mod as it will allow you to reduce the uf value of that last power supply cap allowing a smaller and easier to fit capacitor to be used you should then with some planning still be able to get it in a stock Crack enclosure by only perhaps adding some feet to raise it up a little bit. The choke runs to around $15 and then you should be use a much smaller film capacitor in the 50uf-100uf range.

http://bottlehead.com/smf/index.php?topic=6030.0

 

[Tom-s]

Thanks for that! Inspiring.
I'm also planning on making an extra level with an alloy plate in the crack.
Already did that above the PSU for a CLCLC using extended bolts for the transformer (mounting 2 chokes in crack is tight).
I'll now make the crack 15cm vs the normal 8cm tall. And add the caps (180uf for the last PSU cap) and 2x 90uf for the output. A little more actually with the bypass caps.

 

[Doc B]

A Speedballed Crack plus £200 worth of cap upgrade and extra chokes runs pretty close to the price of a Crackatwoa. I mention this because the Crack with extra caps and chokes will still not perform as well as a Crackatwoa with its shunt regulated power supply. In this particular case you are already deep into the project so I understand your wanting to continue the mod process. But for anyone who is reading this with the idea of buying a Crack and modding it in the future I would suggest considering a Crackatwoa as another possibility.

 

[Tom-s]

I considered crack vs S.E.X (there was no crackatwo back then) and ended up with crack because of the possible mods. It's all about the journey for me.


Edit: Measured again and again. Found out 6 30uf caps won't fit for the PSU. So only 4 will have to do.

 

[Rocketman248]

A Speedballed Crack plus £200 worth of cap upgrade and extra chokes runs pretty close to the price of a Crackatwoa. I mention this because the Crack with extra caps and chokes will still not perform as well as a Crackatwoa with its shunt regulated power supply. In this particular case you are already deep into the project so I understand your wanting to continue the mod process. But for anyone who is reading this with the idea of buying a Crack and modding it in the future I would suggest considering a Crackatwoa as another possibility.

And then you can start modding the Crackatwoa!  ;D

 

[Paul Birkeland]

The operating voltage of the MBGO-2 caps is 160v.
Would it be a problem using these as the last PS cap?

Bad idea!

 

[Tom-s]

Did some further reading on this matter. Thanks PB.
Will not use these in the PSU. Now i just have to find one that will work.

 

[Jeb Jeb]

So I installed a  choke and later replaced the last power supply capacitor with a 250v/100uF film capacitor.  I like the results and much prefer it to just using a bypass on the stock electrolytic, which I felt degraded the sound somewhat.

Yesterday, just before finishing up, I experimented with bypassing this last 100uF film cap in the power supply with a smaller, higher quality capacitor.  Carefully using clip-leads to try some different options and listening closely. I first tried with a little cheap Russian teflon cap. 

I also tried a Jupiter 1uF HT Beeswax Paper 600v. I know this is really getting into crazy boutique diminishing returns territory and, as Doc says, you have to be sensible about the priceerformance ratio.  But I do quite like the results  and would like to stick with it.  Am I crazy for feeling I hear an improvement ?

Can I please ask if it is okay to go ahead and permanently install a cap of this variety as a bypass ? As long as the cap's voltage rating is high enough, is this okay?

Also, it is rated at max temp of 70, whereas I think the stock electrolytic was rated at 85 degrees.

If anything, it seems as though post-speedball the Crack might be running even cooler than before.  But I wanted to check I am not doing anything unwise.

Thank you

 

[Doc B]

It's fine to use as long as you make sure it isn't getting hot enough to melt the beeswax. That has been a problem in the distant past when  using early Jupiter caps in a S.E.X. amp, but I don't recall anyone describing a similar problem using them in a Crack, as it would not be as likely an application. Crack does get pretty warm, so do keep an eye on it.