Search found 302 matches

by guitarmike2107
Wed Nov 15, 2023 9:06 am
Forum: Technical Discussion
Topic: Power transformer fails
Replies: 63
Views: 52051

Re: Power transformer fails

Measure the voltage drop and current with the Weber PT if you can still make it work, then with a new PT measure the voltage drop and current when playing or with signal and work out what resistor size you need. otherwise you will just have to take a guess. You could probably measure the secondary r...
by guitarmike2107
Tue Nov 14, 2023 8:44 pm
Forum: Technical Discussion
Topic: Power transformer fails
Replies: 63
Views: 52051

Re: Power transformer fails

I have a vibrolux custom here, when distorting the 2 6L6's the are drawing 100mA each and the PT runs very hot and sags from 425v down to 380v and lower. Quite a lot for a little 6L6 amp. I suspect that is the sound that Oddvar likes. If you want the sag fitting some resistors before the diodes will...
by guitarmike2107
Mon Jan 30, 2023 7:54 pm
Forum: Trainwreck Discussion
Topic: Liverpool treble cap differences
Replies: 12
Views: 1766

Re: Liverpool treble cap differences

Could be, I was surprised about it when putting the kit together. I am sure Ken had his reasons

If you haven't already, you should download the tone stack calculator and plug in the values to get an idea how cap changes affect the tone stack.
by guitarmike2107
Mon Jan 30, 2023 4:00 pm
Forum: Trainwreck Discussion
Topic: Liverpool treble cap differences
Replies: 12
Views: 1766

Re: Liverpool treble cap differences

Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples. For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or ...
by guitarmike2107
Thu Jan 19, 2023 8:03 pm
Forum: Trainwreck Discussion
Topic: Gradual/fast switch
Replies: 42
Views: 7106

Re: Gradual/fast switch

Don't fit a tiny switch to B+ ever - If you do switch between different coupling caps so there is no DC voltage on the switch. This mod works fine to tame the amp a bit and you can play with the resistor values to get it where you want it. Check out the Pete Thorn Komet demo he did years ago with fa...
by guitarmike2107
Mon Jan 16, 2023 10:55 am
Forum: Trainwreck Discussion
Topic: A few questions regarding my new Liverpool build
Replies: 22
Views: 2112

Re: A few questions regarding my new Liverpool build

22nf on the phase invertor still gives full response, it is what I have in mine and I can't see any reason to make it bigger, might try smaller though. I am going to change the second bypass cap to 0.68uf - for a 2.7k/0.68uf cathode arrangement. Tighter bass and you will probably be able to turn up ...
by guitarmike2107
Mon Jan 16, 2023 10:47 am
Forum: Trainwreck Discussion
Topic: Beginning my Liverpool build!
Replies: 46
Views: 4583

Re: Beginning my Liverpool build!

Reeltarded wrote: Sun Jan 15, 2023 11:57 pm DC on input. Change V1. You need a shield on that amp immediately. You will chase noises that don't exist.
Spot on, these amps need a shield more than any other amps I have built for noise.
by guitarmike2107
Thu Jan 12, 2023 10:00 am
Forum: Trainwreck Discussion
Topic: Beginning my Liverpool build!
Replies: 46
Views: 4583

Re: Beginning my Liverpool build!

Looking good Ledvedder5150, Don't move the OT, it is totally fine there and does not affect the pre-amp valves and it does not pick up hum from the PT. It also leaves space for a choke to be fitted if you want to try that later on too. Take your time and keep things tidy, especially around the pre a...
by guitarmike2107
Thu Mar 24, 2022 4:22 pm
Forum: Technical Discussion
Topic: New Amp - The Lancaster
Replies: 6
Views: 1196

Re: New Amp - The Lancaster

Very nice work. Well done!
by guitarmike2107
Tue Jul 16, 2019 1:23 pm
Forum: Technical Discussion
Topic: Silver Mica treble cap problems.
Replies: 13
Views: 1644

Re: Silver Mica treble cap problems.

Interesting reading this, makes me wonder what the failure mode is.

On some caps if you bend the leads right at the body you can see the outer coating crack around the legs, I wonder if this is letting in moisture??

Or if the caps have just not been up for the job
by guitarmike2107
Tue Jul 16, 2019 1:21 pm
Forum: Trainwreck Discussion
Topic: Rocket voltage issues
Replies: 5
Views: 3162

Re: Rocket voltage issues

I know this post is pretty old, but I recently just finished a Rocket build and seem to be having the same issue as the original post, about 90v on the preamp. Anyone have an idea? Jay 90v on the valve pins or 90v volt at the filter cap? Use Ohm law to figure out where the currents are flowing in t...
by guitarmike2107
Mon Jul 15, 2019 3:47 pm
Forum: Trainwreck Discussion
Topic: Cornell Dubilier vs. SoZo Silver Mica Comparison Clips
Replies: 21
Views: 6857

Re: Cornell Dubilier vs. SoZo Silver Mica Comparison Clips

Heys, old thread, but this sort of thing interests me so I finally got round to trying these caps out and recorded some sound samples

Set it up as a blind test for you here. Answers at the end

https://youtu.be/ifC2A5QkbRY
by guitarmike2107
Fri May 31, 2019 6:14 pm
Forum: Dumble Discussion
Topic: New build- Tweedle Dee-now with sound clips
Replies: 57
Views: 5503

Re: New build- Tweedle Dee-now with sound clips

Cool, Love the demo's you have done of this amp, going to share them on my page if that is ok?
by guitarmike2107
Fri Mar 08, 2019 10:29 pm
Forum: Technical Discussion
Topic: Stripping plexi panels
Replies: 13
Views: 785

Re: Stripping plexi panels

for $10 you could just get a new piece..... I could probably post you a new piece form Scotland for that amount
by guitarmike2107
Fri Mar 08, 2019 9:59 am
Forum: Technical Discussion
Topic: Stripping plexi panels
Replies: 13
Views: 785

Re: Stripping plexi panels

you would have to get the stripped surface looking perfect to not notice it when you re-paint it.
a laser cutting place could cut you a piece to the right size and cut out the holes for you too if you are drilling averse. That is what I would do anyway

Good luck