Search found 302 matches
- Wed Nov 15, 2023 9:06 am
- Forum: Technical Discussion
- Topic: Power transformer fails
- Replies: 63
- Views: 59956
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...
- Tue Nov 14, 2023 8:44 pm
- Forum: Technical Discussion
- Topic: Power transformer fails
- Replies: 63
- Views: 59956
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...
- Mon Jan 30, 2023 7:54 pm
- Forum: Trainwreck Discussion
- Topic: Liverpool treble cap differences
- Replies: 12
- Views: 1910
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.
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.
- Mon Jan 30, 2023 4:00 pm
- Forum: Trainwreck Discussion
- Topic: Liverpool treble cap differences
- Replies: 12
- Views: 1910
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 ...
- Thu Jan 19, 2023 8:03 pm
- Forum: Trainwreck Discussion
- Topic: Gradual/fast switch
- Replies: 42
- Views: 7715
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...
- Mon Jan 16, 2023 10:55 am
- Forum: Trainwreck Discussion
- Topic: A few questions regarding my new Liverpool build
- Replies: 22
- Views: 2269
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 ...
- Mon Jan 16, 2023 10:47 am
- Forum: Trainwreck Discussion
- Topic: Beginning my Liverpool build!
- Replies: 46
- Views: 5077
Re: Beginning my Liverpool build!
Spot on, these amps need a shield more than any other amps I have built for noise.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.
- Thu Jan 12, 2023 10:00 am
- Forum: Trainwreck Discussion
- Topic: Beginning my Liverpool build!
- Replies: 46
- Views: 5077
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...
- Thu Mar 24, 2022 4:22 pm
- Forum: Technical Discussion
- Topic: New Amp - The Lancaster
- Replies: 6
- Views: 1253
Re: New Amp - The Lancaster
Very nice work. Well done!
- Tue Jul 16, 2019 1:23 pm
- Forum: Technical Discussion
- Topic: Silver Mica treble cap problems.
- Replies: 13
- Views: 1752
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
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
- Tue Jul 16, 2019 1:21 pm
- Forum: Trainwreck Discussion
- Topic: Rocket voltage issues
- Replies: 5
- Views: 3264
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...
- Mon Jul 15, 2019 3:47 pm
- Forum: Trainwreck Discussion
- Topic: Cornell Dubilier vs. SoZo Silver Mica Comparison Clips
- Replies: 21
- Views: 7069
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
Set it up as a blind test for you here. Answers at the end
https://youtu.be/ifC2A5QkbRY
- Fri May 31, 2019 6:14 pm
- Forum: Dumble Discussion
- Topic: New build- Tweedle Dee-now with sound clips
- Replies: 57
- Views: 5799
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?
- Fri Mar 08, 2019 10:29 pm
- Forum: Technical Discussion
- Topic: Stripping plexi panels
- Replies: 13
- Views: 878
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
- Fri Mar 08, 2019 9:59 am
- Forum: Technical Discussion
- Topic: Stripping plexi panels
- Replies: 13
- Views: 878
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
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