Do these caps look bad?

[phyrexia]

This is a technical amp question and I think the Vintage Amps section is the best place for it, because it seems like the tech-heads hang out in here.

I typed a longer question and the forum lost it. I'll be brief.

My D180 is microphonic. I have isolated it to the two inside preamp tube sockets, but the tubes themselves are not microphonic. They are brand new and I've replaced them with two other brand new 12AT7s to no avail. (the dymo tape on the amp itself calls for 12AT7s).

I have heard that caps can be microphonic, so I opened the chassis up and I noticed that all the orange drop caps look bloated. Does anyone agree with me? Could one of them be the culprit?

I'll have higher quality pictures later tonight.

Thanks
Victor

 

[Boogiebabies]

So far, they look fine to me.

 

[Shep]

if something inside your amp is microphonic.. pull it out and plug everything in normal and turn it on.. turn the controls up a bit and start lightly tapping everything with a chopstick or something like that (non conductor)t.. don't touch anything with your hands inside the amp unless you want to die.you will die..but if you tap something and you can hear it thought the amp.. well thats the problem..

T

 

[fdesalvo]

Ah, Orange Drops. Like Shep said- I think it's somethign to do with the layout. Take a chopstick or another non-conductive stick and move around some of the wires around the input, preamp grid wires, etc... and see of it improves things.

How old is that amp? I would refresh the caps if they are over 10 years old.

 

[phyrexia]

9/82 I think?

http://www.dpo.uab.edu/~vwilson/mkiii/d1801.JPG <-- 1MB

They just look fat. The spragues I've seen before have been neater shapes, more regular, I suppose. I haven't taken chopsticks to anything on the board; I've only tapped the tubes and chassis.

All of the filter caps look fine actually.

 

[stokes]

Those orange drops dont usually "look" bad if they are.They rarely go bad.If they do they generally leak dc voltage,this can be checked by disconecting the cold side of the cap and checking for dc volts there.To see if they are overly microphonic,tap them with a chopstick with the amp on and connected to a speaker and listen like you would do for a micrphonic tube.Changing them doesnt always cure it,the cap is not necessarily bad because it is microphonic.

 

[MrMarkIII]

Do these caps make me look fat?

 

[phyrexia]

i think it is just a tube after all.