Search found 1194 matches

by sliberty
Fri Dec 22, 2017 9:31 pm
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

That trem circuit has been used in several Fender amps. The circuit works well. I'm suspecting layout issues or maybe even a wiring error. One thing to try would be move the trem oscillator B+ supply from the plate node cap to the screen node cap to provide more filtering. That plate node is pretty...
by sliberty
Fri Dec 22, 2017 9:29 pm
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

Ok, that helps to know what sort of noise you have. So the LFO is actually still oscillating, in a way? Maybe you are aware, but the usual practice for reducing the LFO frequency is to replace one or both of the 0.01u with 0.02u, keeping the RC phase shifts approximately equal The suggestions I've ...
by sliberty
Fri Dec 22, 2017 6:05 pm
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

Lifting the global feedback did not eliminate the noise.
by sliberty
Fri Dec 22, 2017 5:53 pm
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

I'll try the feedback loop suggestion next. I am also going to amend the description of the noise. It is a loud rhythmic popping sound. It pops at a speed that seems to be related to the phase shifts in the feedback loop of the oscillator. By that I mean that if I ground at the usual place between t...
by sliberty
Fri Dec 22, 2017 12:51 pm
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

There are three Caps in the feedback circuit. The normal place to ground is between the .01’s, and I get noise there. I also tried between the .01 and the .02, and got noise there as well. As for the cathode, I’ve lifted the cathode, and that stops the Trem, and emits no noise. As for grounding in d...
by sliberty
Fri Dec 22, 2017 3:35 am
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Re: Odd 6G2 Bias Trem Problem

Thanks for the reply. I have tried several known good tubes in both V2 (which includes the oscillator) and V1 (just because). No difference. As for lead dress, I was afraid someone would say that :) Frankly, lead dress is black magic to me. I don't know any of the do's and don'ts that I should be wa...
by sliberty
Fri Dec 22, 2017 12:50 am
Forum: Fender Discussion
Topic: Odd 6G2 Bias Trem Problem
Replies: 20
Views: 4042

Odd 6G2 Bias Trem Problem

I built a Fender 6G2 copy some time ago, but never bothered hooking up the foot switch for the trem. This week, when I tried to do so, I discovered that closing the switch (grounding the oscillator RC network) resulted in a loud sputtery noise (the trem did stop of course). Removing the footswitch, ...
by sliberty
Thu Jul 20, 2017 10:57 pm
Forum: Technical Discussion
Topic: Transformer replacement advise needed
Replies: 5
Views: 725

Re: Transformer replacement advise needed

The PT was 100mA on the high voltage, which is more than enough for a Princeton, 3A on the heaters, and 2A on the 5V tap. I think spec wise I should have been fine. I'll probably play it safe and replace the main components in the bias supply (cap and diode) and maybe the filter caps as well. As for...
by sliberty
Thu Jul 20, 2017 9:06 pm
Forum: Technical Discussion
Topic: Transformer replacement advise needed
Replies: 5
Views: 725

Transformer replacement advise needed

A few years ago, I built a 6G2 Princeton, and used a Musical Power Supplies PT325.2 for the power transformer. This amp has seen only light use until 2 months ago. Then I started using it at the Wed blues jams, so it at least got a few hours per week of use by me (and maybe more when I wasn't there)...
by sliberty
Wed Apr 12, 2017 10:51 am
Forum: Trainwreck Discussion
Topic: OT for a rocket?
Replies: 9
Views: 1894

Re: OT for a rocket?

I've only ever used the Dynaclone from Triode as an OT in my Rocket builds.
by sliberty
Sat Apr 08, 2017 12:18 pm
Forum: Trainwreck Discussion
Topic: Reducing gain in a wreck?
Replies: 26
Views: 4443

Re: Reducing gain in a wreck?

I did this by installing a split plate load on the third (I think) stage. You can modify the split to taste (50k/50k, 22k/82k, 82k/22k, etc). I love the results. This can also be switchable, whee one position engages the split, and the other position goes back to stock.
by sliberty
Wed Mar 15, 2017 11:16 am
Forum: Trainwreck Discussion
Topic: Liverpool to Rocket conversion :)
Replies: 10
Views: 1493

Re: Liverpool to Rocket conversion :)

I've also used the VVR with my Rocket builds and had great results.
by sliberty
Mon Mar 13, 2017 11:12 am
Forum: Trainwreck Discussion
Topic: Liverpool to Rocket conversion :)
Replies: 10
Views: 1493

Re: Liverpool to Rocket conversion :)

Glad you are happy with the results. Rockets are wonderful amps. And the higher gain of the Liverpool/Express certainly isn't for everyone. It's worth mentioning that there are ways to tame these amps a bit. In my Express, I used a split plate load, which you can configure to taste (50/50, 75/25, 25...
by sliberty
Thu Feb 23, 2017 5:05 am
Forum: Garage Talk
Topic: Macbook guitar interface
Replies: 8
Views: 1314

Re: Macbook guitar interface

I use a Steinberg UR12 with my Mac Mini. I bought it because it also supports the iPad, which many other interfaces do not. One interface for two computing devices is a real plus for a cheapskate like me. And the bonus is that it is a nice, good sounding interface.

Worth checking out.
by sliberty
Sat Feb 18, 2017 7:07 am
Forum: Vox/Hiwatt Discussion
Topic: AC10C1 schematic
Replies: 5
Views: 4654

Re: AC10C1 schematic

Yea, I kind of figured that. Was hoping someone with a connection might have access to it. Or perhaps someone might have drawn one themselves, like the AC4C1