Hi
I am working on this amp which look very old. The complaint is that the tone sounds dirty. All the caps are OK, I was told they have been replaced quite recently. Almost all of the resistors have changed value, they are reading around 20% higher. The 100K resistors are reading 121K. Will this change in resistance effect the performance of the amp. Please advise.
Thanks
I am working on this amp which look very old. The complaint is that the tone sounds dirty. All the caps are OK, I was told they have been replaced quite recently. Almost all of the resistors have changed value, they are reading around 20% higher. The 100K resistors are reading 121K. Will this change in resistance effect the performance of the amp. Please advise.
Thanks
there's so many iterations of the Showman that unless you id which version it's hard to say.
for resistors this far off tolerance i'd not trust that caps "where recently replaced".
for resistors this far off tolerance i'd not trust that caps "where recently replaced".
What does that mean?
* Tone controls sound "dirty"? (Scratch sound when they are rotated)
* "Amp Tone" is "dirty" meaning amp sounds distorted?
Pick one.
Well, if those +20% 100K are plate resistors in multiple stages of tube gain, yeah, I think their upward drift could cause the whole amp to sound "dirtier".
Do you have the option and parts to change them for your customer? If so, you'd have to replace all of them - and then see if the amps character changed back to "cleaner" according to your customers perception.
Do you have the option and parts to change them for your customer? If so, you'd have to replace all of them - and then see if the amps character changed back to "cleaner" according to your customers perception.
Carbon Composition drifts, usually up, true. But for "all" resistors to drift the same way the same amount would be very odd.
I'm sure this was posted on another forum and I suggested replacing the meter battery. A low battery is a low Vref so the DMM's technique will read all the Ohms high. But I can't find that post.
I'm sure this was posted on another forum and I suggested replacing the meter battery. A low battery is a low Vref so the DMM's technique will read all the Ohms high. But I can't find that post.
I remember reading a post where a Vox AC-30 was 'noisy" and the tech solved the noise problem by changing ALL the anode resistors from carbon comp to metal film.