Output Capacitor Upgrading Questions

[corndog71]

Could you elaborate?

Say if I wanted to bypass a set of 100uF Evo Oils with a 1uF cap, would the 1uF cap's attributes show?

Possibly.  Or it could make it sound worse.

In the signal path electrolytics generally don't sound as good as a film cap.  I'm not smart enough to explain why, it's just a phenomenon I've encountered as have other folks.  That's not saying it won't work or even sound bad.  Since the Crack has such a huge output cap it's cheaper to stock it as an electrolytic.  Bypassing it may help smooth out the sound of the electrolytic but it's kind of a band-aid for a compromised situation.  Swapping the electrolytic with a single film cap is IMO the best "upgrade" solution.  No need for a bypass because it's no longer a compromised situation.  Of course you're welcome to try adding the bypass and hear it for yourself.  It's your money.

 

[Tom-s]

I didn't really notice much of the FT-3 teflon bypass when i put them in.
So after 1000+- hours (a few months later), i removed them. I immediately noticed something was missing.
This is with 90uf paper in oil caps for the output.

 

[ohshitgorillas]

A friend of mine gave me some vintage Russian NOS 1uF paper-in-oil caps for bypasses on my Crack's output caps, and a third for bypassing the last cap in the power supply (which I've replaced with a 100uF film cap). To my ears, there is better impact/slam but otherwise I don't hear much. I'm not complaining since I got them free but it's not something I'd spend my own money on.

 

[Julyan9]

Hello!

Just installed some mundorf Mcap 100uf/250V and now the big board leds are all dim. Anyone else have this happen after output cap swap?

 

[Paul Birkeland]

Hello!

Just installed some mundorf Mcap 100uf/250V and now the big board leds are all dim. Anyone else have this happen after output cap swap?

I would recommend starting a new thread and posting your voltages.  Dim LEDs don't really mean anything unless you measure the actual DC voltages. I bet you'll find some that aren't what they are supposed to be!

 

[manther]

Bit of a weird question here but, Ive ordered some film caps for my crack. I use the crack 50/50 as a headphone amp and as a pre-amp to my Sony power amp. My Sony is an old TA-3200f that I recapped. I carefully chose nice electrolytic nichicon caps. They are nice but probably not as nice as the film caps I'll be using in the crack. Question is (and this is probably unanswerable) how much of the capacitor work (or tube rolling for that matter) is being dilluted and or wasted down-path from the crack when I use it as a pre-amp? I looked into replacing the caps in the audio board on my Sony. It was all fine until I got to the largest 470 caps. I'd have to do bypasses on those.

 

[Paul Birkeland]

That would be something you would have to experiment with, since there can be a lot of variables in the amplifier/speaker realm.

 

[manther]

Thanks. Just got done replacing the two output capacitors with 100uf audyn Q4's. I'm measuring resistance on 7 and 9 before going any further and the resistance is maxing out my multimeter. No longer in the 2.9k ohm range. Is this normal or a problem?

 

[Paul Birkeland]

Thanks. Just got done replacing the two output capacitors with 100uf audyn Q4's. I'm measuring resistance on 7 and 9 before going any further and the resistance is maxing out my multimeter. No longer in the 2.9k ohm range. Is this normal or a problem?

Do you have the Speedball installed?

 

[manther]

Yes I do.
I actually went back and redid all the resistance checks listed in the original crack guide and also the speed ball guide. Everything checks fine except 7, and 9 are over limit.

 

[Paul Birkeland]

Well, you take out the 2.9K resistors that attach to 7 and 9 when you install the Speedball.

 

[manther]

Ah, thats right. Thank you.

 

[Jamwagon]

Hey everyone, I'm sure this has been covered before somewhere, but I've done a bit of searching and can't find a super definitive answer.

I was wondering if it's okay to upgrade to output caps with a microfarad rating a little below 100 like these:
https://solen.ca/products/capacitors/fast-capacitors-250v-pa-series-metallized-polypropylene/pa9100/
Or if I should really use the other with a 100uf rating minimum.

Honestly I'd like to use the 91uf 250v Axon true caps but partsconnexion's selection stops at 43uf. https://www.partsconnexion.com/axon-true-cap-film-capacitors.html
I'm going to contact them tomorrow to see if they can get higher values ordered and if not then I'll probably just stick with the solens. I've pretty much come to conclusion that everything around this price range is going to offer similar performance (Audyn, Solen, Dayton, Erse PulseX, Jantzen, etc) so I'm more focused on price/value and physical size/ease of install.

Thanks

 

[Jamwagon]

Bump.

 

[Paul Birkeland]

Give it a shot and let us know how you like it!

 

[Jamwagon]

Whoop! Will do. FYI, according to partsconnexion, Axon is no more. So I'm going with the 91uf Solens straight from CA.

 

[elmoe]

I noticed this picture in a different thread as a way to mount the capacitors:

https://bottlehead.com/smf/index.php?action=dlattach;topic=6030.0;attach=5468;image

Is this safe to do? It looks like a hole was punched in the plate, and a screw was inserted then locked in place with a nut. It was then used to solder the caps to directly and wired where necessary.

 

[Paul Birkeland]

Is this safe to do? It looks like a hole was punched in the plate, and a screw was inserted then locked in place with a nut. It was then used to solder the caps to directly and wired where necessary.

That's an insulated turret.  Here's an example:
https://www.mouser.com/ProductDetail/Keystone-Electronics/11511?qs=sGAEpiMZZMsg%252Bek5lc7F5m87vzA%252BVXoK

This is a very, very good way to mount big capacitors, but that's $25 worth of parts to serve that purpose.

 

[Jamwagon]

Very interesting! Cost is definitely a factor. I still haven't picked up any upgrade caps but someone mentioned automotive Velcro as it has a much higher temperature rating. Can be found on Amazon. I figured I would start there.

 

[elmoe]

That's an insulated turret.  Here's an example:
https://www.mouser.com/ProductDetail/Keystone-Electronics/11511?qs=sGAEpiMZZMsg%252Bek5lc7F5m87vzA%252BVXoK

This is a very, very good way to mount big capacitors, but that's $25 worth of parts to serve that purpose.

Thank you!