Who has re-capped their Red Bear?

[Matt300ZXT]

I'm restoring my MKE 120 and want to replace the filter caps while I'm in there. I've got the old ones out, but unfortunately I have yet to find a place that makes direct replacements. I am not opposed to refitting more common caps in place but the values someone told me are rather hard to find and I just haven't seen any information on what people did to recap their amp.

Any help or insight would be greatly appreciated.

[Stevem]

I am not familiar with the amp as many other likly are also here, can you post some pic's of the filters and post there values you need?

[Phil_S]

According to the schematic I found online, there are 3x 50uf 400V and one 22uf 350V. These should be fairly easy to find. The exact value isn't critical. The voltage rating should be at least what is there now.

For the 22uf, use 20, 22, or 25uf. You should be able to find 350V rated, but 450V is just as good, though it may cost more and may be physically larger.

For the 50uf, the nearest common value is 47uf and that should be fine. Given the tolerance rating, there is no meaningful difference. You'll probably find them in 450V rating.

I don't know if you need can type caps, axial lead, or radial lead. Ignoring form factor, here are a few examples of appropriate caps:
https://www.tubesandmore.com/products/C-EC50-50-500
https://www.tubesandmore.com/products/C-ET47-500-FT
https://www.tubesandmore.com/products/C-ET22-350
https://www.tubesandmore.com/products/C-ET47-450
The list goes on. Just search a little bit and you'll find what you need.

Post a picture or two. It may prove helpful in getting a recommendation.

[Matt300ZXT]

Where did you find that info Phil? The schematics I found are so small it's hard to read anything on there, let alone specific numbers. Another guy on a guitar gear forum says he saw 4 100uf 350v and 1 50uf 400v. However, mine has 6; 4 taller skinnier ones, and 2 shorter fatter ones.

I'll post a pic. I'd love to find stock style with the threaded body, but I'll likely have to get some JJ caps or something, drill the holes slightly larger (they're only 1/2") and get clamps so I can install the newer style, which isn't really a big deal. Since these caps only have 1 lead, I'm assuming the body acts as the negative lead and grounds when installed. I did find 1 pic where someone had put in newer 2 pole can types and just soldered the negative lead straight to the copper plates the caps are poking through.

p.s. Phil, I did find last night I am able to install caps of higher uf and voltage ratings after I posted this, so that'll make it so much easier on me finding a good cap to use, it's mostly just fancy ways to mount caps that I'm looking for since the only similar caps I'm finding are NOS Russian and I'm not using a cap that's at least 20 years old off the shelf.

[Matt300ZXT]

As you can see in the pics, on the left hand side, there are 6 holes. 4 with copper plates, 2 without. That's where the filter caps go. I wish they had a nice board with the power section's caps on it like the Peavey VTM I re-capped, or the SLO clone I was building. Oh well, I guess Russia had their own way of doing things

[Phil_S]

Page down to see the hand drawn schematic.
http://www.prowessamplifiers.com/schema ... K_120.html

You've got lots of room inside. You can probably find those threaded caps, but I expect you'll spend more money and won't get any value for it. If this was my amp, I'd do one of three things:
1) mount clamps on top for can caps or
2) build a cap board for axial caps and mount it inside, or
3) mount can cap clamps inside for horizontal mount if the caps are too big for vertical mount.

If you are really set on screw mount type, try searching Mouser, Digikey or other big house of that type.

[Matt300ZXT]

Yeah, that's the schematic I'm talking about. You must have super human eyes to be able to read that. Any time I've tried blowing it up to clearly see the numbers, it looks like an alien language it's so jacked up. I printed it out and it's a liiiiittle better but not by much.

[Phil_S]

Plain as day on the hand drawn...attached, red circled.

[Matt300ZXT]

Oh, yeah well I saw those numbers lol I'm talking with a guy in Europe who has worked on his before, he has the information on the other caps that aren't listed that are on the impossible to read schematics. He said he redrew the entire amp schematic on 1 file so everything can be seen. He's going to dig it up for me tomorrow. He also gave me some cool ideas on mounting newer style axial caps if I want to use those.

[Phil_S]

It's always possible for a coupling cap to have gone bad, but I'd focus on the electrolytic caps first.

OK, so I missed a few...

There is a pair of 100uf in series for the plate supply. Voltage listed for the circuit is 495V. Replace these with a single 47uf 600V cap.

There is a pair of 50uf in series for the screen supply. Replace these with a single 22uf 600V or 33uf 600V. Maybe you can find a 25uf 600V.

There are a couple of small caps (15u 600V?, 0.25 600V?) between the PT and the bridge rectifier and a couple of caps (10u, 4.7u; 100V should be plenty) on bias circuit. I imagine the exact values are not critical in these locations.

Good luck.

[C Moore]

http://newsensor.com/ContactUs.aspx
Cannot remember the guys name at Reflektor.....but they should know.?
good luck