Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: evancorylevine on August 06, 2017, 07:31:44 pm

Title: New AC30 Build - Tremolo not working - Crackling with EQ?
Post by: evancorylevine on August 06, 2017, 07:31:44 pm
Good evening, y'all!

I just built a Weber AC30 and I had everything working great, but the chassis was super microphonic, so I moved some tubes around, got the microphonic stuff to go away, but now my tremolo isn't working. I get a clean signal that doesn't change between trem and vib. Sounds just like the normal channel.

Any idea what I should be doing? Should I be ordering new tubes? checking some of the other components?

Also, is it normal to get crackling and other sounds when adjusting the treble and bass? It doesn't sound like a dirty pot. It sounds like audio noise, or sometimes a bit of a thunk. I think the sound was cutting out altogether when treble was all the way down.

I eagerly look forward to your advice. You all have been so helpful. I am very grateful.

-e
Title: Re: New AC30 Build - Tremolo not working - Crackling with EQ?
Post by: sluckey on August 06, 2017, 08:04:32 pm
Tremolo circuit needs a strong tube.
Title: Re: New AC30 Build - Tremolo not working - Crackling with EQ?
Post by: shooter on August 06, 2017, 08:09:15 pm
Quote
is it normal to get crackling and other sounds
um, no, crackling can be lots of things, bad soldering, bad socket, dirty stuff.........

other sounds, I'm thinking that's why we build :laugh:
Title: Re: New AC30 Build - Tremolo not working - Crackling with EQ?
Post by: evancorylevine on August 08, 2017, 03:37:47 pm
okay! crackling is basically gone.

when I pull the trem/vib pot to turn on the trem, there's a loud snap in the speaker. Any ideas?

Also, are there mods to increase the range of the speed and depth? I find that the speed could stand to be wider, and the depth could stand to be mellower.
Title: Re: New AC30 Build - Tremolo not working - Crackling with EQ?
Post by: sluckey on August 08, 2017, 03:51:42 pm
Quote
... are there mods to increase the range of the speed and depth? I find that the speed could stand to be wider, and the depth could stand to be mellower.
Yes. I replaced the depth preset pot with a front panel pot for complete user control of the depth. And I added a switched cap to extend the slow speed of the oscillator. You can see the mods on my schematic of the AC-15 which has the same trem/vib circuit as your Weber amp. Schematic at bottom of this page...

     http://sluckeyamps.com/VAC15/ac15.htm (http://sluckeyamps.com/VAC15/ac15.htm)