Opinions on large Cornell Dubilier 383LX caps for Power Supply?

Mr. Yamaha

Mr. Yamaha

Not so much Yamaha lately...
Hello,

I'm in the process of a search for caps voor recapping my Yammie M-4 and came across the Cornell Dubilier 383LX, that makes me able to fit 2x 22.000 uF 80v caps for the power supply.

Any opinions on this brand, type or usage of these for power supplies? The physical size is perfect, same diameter and only 2 mm higher.

M-4 is standard fitted with Nichicon 15.000 uF 75v caps which are discontinued.

Any experiences or information will be helpful!

Link: http://www.cde.com/catalogs/381-383.pdf
 
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I use a lot of CD caps in tube amps builds. I use a lot of high voltage electrolytics that look a lot like the caps in your link. I like them a lot. I'd use them again, for sure.
 
I have rebuilt a Fisher 600-T and have another one that will be rebuilt with major redesign (will start a thread in the Fisher forum sometime in the future). Since I am replacing ALL electrolytic capacitors, the main power supply is equipped with CDE 382LX103M100N062, 10,000 uf, 100 volt capacitors. These replaced 3000 uf, 40 volt originals and, same as you, I selected based on diameter so they would fit in the same holes with the same clamps.

Due to the much higher capacitance, I also replaced the unidentified, house numbered rectifier diodes (inexpensive) just to make sure they would handle the increased turn on surge.

My spec sheet is for the 380 / 382 and yours is 381 / 383. The main difference seems to be that the 380 / 382 is rated for 85 degrees C and the 381 / 383 is 105 degrees. The other specs appear to be the same.

My restored to operation unit has been in almost daily service a few hours every evening (it's on the workbench) for 4-5 months, so no long term reliability info yet, but the supply is very clean and the caps do hold a good charge for several days with no load (as I discovered when working on the unit).
 
I use these..with a 10mm pvc spacer glued to the bottom side . Solder lengths of solderwicking to the required snap-in pins and run them down through the circuit board.

http://www.digikey.com/product-detail/en/382LX183M100B082VS/338-1989-ND/2256597

You can then use the existing hardware for securing the caps.
If you get the 90mm length. You will need to make additional holes in the PC board to properly space them so the existing hardware can be used. If they are any longer than 90mm you will need to modify the existing hardware.
 
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Thanks for your advice!

These CD's are with 5 leads (2x positive, 2x negative and 1x dummy). I believe the standard Nichicons are with three leads (1x positive, 1x negative and 1x dummy).

Should I interconnect the two positives with each other and the two negatives with each other, or can I just use one negative lead and one positive lead and remove the two extra leads?
 
Yamaha M-70 said:
Thanks for your advice!

These CD's are with 5 leads (2x positive, 2x negative and 1x dummy). I believe the standard Nichicons are with three leads (1x positive, 1x negative and 1x dummy).

Should I interconnect the two positives with each other and the two negatives with each other, or can I just use one negative lead and one positive lead and remove the two extra leads?
Click to expand...

Just use one neg. pin and one pos.pin.
 
you can also use screw-terminal solder lugs and then use any screw-terminal capacitor. if you bend the lugs down 90 degrees, it will be functionally identical to the original lugs on the Nichicons and drop right in
 
Yamaha M-70 said:
Thanks for your advice!

These CD's are with 5 leads (2x positive, 2x negative and 1x dummy). I believe the standard Nichicons are with three leads (1x positive, 1x negative and 1x dummy).

Should I interconnect the two positives with each other and the two negatives with each other, or can I just use one negative lead and one positive lead and remove the two extra leads?
Click to expand...

Mine are 4 terminal. The negative terminal is next to the black stripe on the body. The other 3 terminals are on the other side and one of them has a small "+" embedded in the metal of the actual terminal. The data sheet specifically states that the other 2 terminals are not to be connected because they have some sort of internal connection in the capacitor. Those terminals are mainly to ensure proper orientation on mass produced circuit boards.

Look for the "+" on one of the terminals opposite the negative terminal, the one next to the black stripe. The data sheet is not clear on the 5 temrinal.
 
fred soop said:
Mine are 4 terminal. The negative terminal is next to the black stripe on the body. The other 3 terminals are on the other side and one of them has a small "+" embedded in the metal of the actual terminal. The data sheet specifically states that the other 2 terminals are not to be connected because they have some sort of internal connection in the capacitor. Those terminals are mainly to ensure proper orientation on mass produced circuit boards.

Look for the "+" on one of the terminals opposite the negative terminal, the one next to the black stripe. The data sheet is not clear on the 5 temrinal.
Click to expand...

Looking at the bottom with Negative sleeve stripe at 12 o'clock. clockwise
- >Negative
A > Negative or isolated
B > do not connect
C >Positive
D > Positive or isolated

You can use - or A for negative
and C or D for positive

The (-),A,B,C and D are labeled on the sleeve as well as stamped in the base of the snap-in pins.
 
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Squidward said:
I use a lot of CD caps in tube amps builds. I use a lot of high voltage electrolytics that look a lot like the caps in your link. I like them a lot. I'd use them again, for sure.
Click to expand...

+1 on on that, they are all I use for power supply caps for my tube gear. Relatively low ESR and high ripple handling. I started using them for the ripple capabilities (to loose any hum) and stuck with them. Good selection of voltages too.

Are you going to bypass those caps at all?? If so whats the recommended bypass cap to use with this amp there? I'm going to work on one for my summer time amp to sub in for tubage during the summer doldrums.

Cheers,
Bob
 
I don't know if the M-4 has bypass caps for the large power caps. I'm planning on letting everything as original possible except for the electrolytics.

Why would I need to bypass them?
 
Yamaha M-70 said:
I don't know if the M-4 has bypass caps for the large power caps. I'm planning on letting everything as original possible except for the electrolytics.

Why would I need to bypass them?
Click to expand...

I was just throwing that out there to see if anyone has done it when recapping the power supply in this unit. Basic reason for using a bypass cap with large electrolytics like used in the M4 is that a large electrolytic capacitor becomes inductive at high frequencies so the bypass cap supposedly will clean up the high frequencies. Not trying to highjack the thread here just asking if anyone else has bypassed those caps in the PSU on the M4??

Cheers,
Bob
 
If you are looking to bypass the filter caps to intercept noise on the normal AC, if you want full effectiveness across the likely expected range of noise, from transients to the data signals for smart meters and BPL, you would want to use 0.1, 0.01, 0.001 uf and a 100pf cap (mylar for the larger values and a simple ceramic or silver mica for the 100pf cap) 630 WV or 1000 WV- all in parallel and tying from the positive and negative voltage rails (at the respective filter cap) to chassis ground. This will act as a shunt to those higher frequencies that might cause problems for the filter caps.
 
I'm not really planning on making changes in Yamaha's respected design. Or do I need to bypass the power caps due to the increase of capacitive value from 15,000 uF to 22,000?
 
I think
trio
Click to expand...
was referring to the small caps values found in psu's in amps that have low thd. I don't think that's modifying an original design except for reducing hi freq. from the get go.

i.e. got an onkyo tx-36 to fix with two 10k caps and small value caps in the design. thd is 0.04% rated power with an stk. ,not bad.
 
Yamaha M-70 said:
I'm not really planning on making changes in Yamaha's respected design. Or do I need to bypass the power caps due to the increase of capacitive value from 15,000 uF to 22,000?
Click to expand...

No you don't need to for raising the capacitance. I only asked if anyone else has done it on the M4. For line noise I always install a X2 cap across the line and neutral that quiets down and filters out most all high frequency noise coming in on the line the PSU does the rest. Back in the day the amp manufacturers put ceramic caps on the inputs outputs and in circuit to get rid of any HF noise that could wreck havoc, I'm sure they still do. I prefer poly caps for bypass in place of ceramic they should last a lot longer but that's splitting hairs, 30 years from re-cap... the new owner might appreciate. :thmbsp:

Cheers,
Bob
 
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