This is my first post on you site , I do apologize for asking the same questions others have made but I seem to be having a hard time gathering what I need. I only have two simple questions:
On the older 555 what is the value of the bypass caps to be across the larger 15k caps.
Second: Where do most purchase the replacement 15k@100vdc caps at?
I have checked around any anything close at Mouser has a 14wk lead time. I was thinking of replacing them with a low ERS, high ripple cap @105c. Nichicon has such a cap p/n=LNT2A153MSE that looks good but same long lead time. There is also some 18k@100vdc on EBAY but I have no idea if these are counterfeit and I do not want to change the value of the cap. Please any suggestions would be great. I used to work in the audio field in the 70’s at Solid Sound in Bolder and M.E.R in Denver, so I do have a good background in repair.
On the older 555 what is the value of the bypass caps to be across the larger 15k caps.
Second: Where do most purchase the replacement 15k@100vdc caps at?
I have checked around any anything close at Mouser has a 14wk lead time. I was thinking of replacing them with a low ERS, high ripple cap @105c. Nichicon has such a cap p/n=LNT2A153MSE that looks good but same long lead time. There is also some 18k@100vdc on EBAY but I have no idea if these are counterfeit and I do not want to change the value of the cap. Please any suggestions would be great. I used to work in the audio field in the 70’s at Solid Sound in Bolder and M.E.R in Denver, so I do have a good background in repair.
Yup! Like a moth to a candle when I saw "555"
Digi-Key has some that might be suitable e.g. Digi-Key - P13203-ND (Manufacturer - ECE-P2AA153HA)
That's a very big "bypass cap". I think we're talking of those greencaps and axial polyester film types that were common fits across electros. These seem to be arbitrary at 100-500nF. I believe someone claimed that the inductance of big electros prevented them from properly bypassing high frequency noise. A 100nF capacitor would solve the problem by "taking care of the high frequencies" That someone may also have had a healthy sales increase thereafter. '
I'm glad you shared the MKII with us, it has the big bypass caps I mentioned on the circuit board, the GFA555 does not have them. They will be shot by now, I hope you are replacing all the electrolytics in this amplifier, not just the main filter caps.
The tiny do-nothing cap mounted to the main electrolytics was about 0.01µF if I remember correctly.
The tiny do-nothing cap mounted to the main electrolytics was about 0.01µF if I remember correctly.
I will be replacing all the cap’s on board with Nichicon “KZ” series, other than the big 15k/110vdc caps. I was thinking of using the Nichicon “LNT2A153MSE” for the 15k’s unless anyone has a better solution. I do not want to increase the filter size in this area if possible. The lead time on that cap is 12-14 weeks; I would like to find a suitable replacement earlier than that if possible. I was also considering replacing the bridge rectifiers at the same time. There has been some talk around the forums as to the use of the hexfreds, I do not want to change the sound of the amp just restore it back to its former youth. I am not looking for the “monster mods” for this amp, so if anyone has any other suggestions as to the passive device replacements please let me know. I do appreciate any time the community could give.
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