Hi all!
I have recently built 2 identical 5f1 amps. The first one is great! no issues to speak of now. It works as it should and is super quiet...I just finished the 2nd one and there is a REALLY loud buzzing sound when I turn the amp on. Playing a guitar through it works...but the buzz is really quite loud to make it unusable. This is not an issue with my first build....
I have gone through and made sure everything is IDENTICAL, which it is.
My question here is: Is this possibly a bad filter cap? How would I know?
I am running a 47Uf, 16Uf, 10Uf for filter caps in this and all are F&T brand caps. FYI the amp is SS rectified as well.
Any ideas?
new 5F1 build with really loud BUZZ
Moderators: pompeiisneaks, Colossal
Re: new 5F1 build with really loud BUZZ
Let's talk about your heater filaments. Is the filament string referenced to ground via 100 ohm resistors or other means?
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Re: new 5F1 build with really loud BUZZ
no there is no faux center tap. There isn't on the amp that is dead quiet either.
Re: new 5F1 build with really loud BUZZ
You did not explicitly say, so I have to ask: Is there a true heater CT? Where is it grounded?freakshow__ wrote: ↑Mon Nov 15, 2021 9:17 pm no there is no faux center tap. There isn't on the amp that is dead quiet either.
I build and repair tube amps. http://amps.monkeymatic.com
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Re: new 5F1 build with really loud BUZZ
No there is no heater center tap on either amp. real or faux
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Re: new 5F1 build with really loud BUZZ
I added the 100 ohm resistors to ground ref. and it's dead quiet now....
so my question is:
Why is one amp quiet WITHOUT the faux center tap, and one Buzzes like crazy without it? Everything is identical on these 2 amps?
so my question is:
Why is one amp quiet WITHOUT the faux center tap, and one Buzzes like crazy without it? Everything is identical on these 2 amps?
Re: new 5F1 build with really loud BUZZ
Are the PTs identical? If not, does the quiet one have an internally grounded filament center tap?
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Re: new 5F1 build with really loud BUZZ
they are both the same PT which I got at the same time.
Hammond 270DAX model
Hammond 270DAX model
Re: new 5F1 build with really loud BUZZ
I bet your first built would benefit from an artificial CT also.