dmp

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #140 on: May 05, 2017, 11:34:21 AM »
Quote
Thanks Bern, it's the 5402 the problem, i actually checked the wiring to be sure and it just doesn't sound right with the 5402. it actually distort quite a lot and the overall low end is definitely lower.

The circuit can't drive a output transformer well, much less a 1:1 ratio. At a minimum you would want a 15k:600 (5::1 ratio) but then you lose gain and would need makeup gain to have line level. In my testing, even with a 10:1 step down output transformer the tone suffers.
I am working on adding a makeup gain stage that can drive a transformer as a solution.
As designed, I think this works great for unbalanced in, unbalanced out at instrument level but it does not work for balanced in/out with line level.


bernbrue

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #141 on: May 05, 2017, 11:40:06 AM »
You're probably right. A cathode follower as final tube stage would have been fine for transformer balanced output. I've used mine completely unbalanced and that work great.
Bernd

gaetan

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #142 on: May 06, 2017, 05:01:03 AM »
The circuit can't drive a output transformer well, much less a 1:1 ratio. At a minimum you would want a 15k:600 (5::1 ratio) but then you lose gain and would need makeup gain to have line level. In my testing, even with a 10:1 step down output transformer the tone suffers.
I am working on adding a makeup gain stage that can drive a transformer as a solution.
As designed, I think this works great for unbalanced in, unbalanced out at instrument level but it does not work for balanced in/out with line level.

I have some spare Gyraf srpp pcbs, might do the trick.

gaetan

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #143 on: June 08, 2017, 07:12:21 PM »
With some serious head scratching, lots of fails, i managed to get it to work with a gyraf SRPP circuit so i get balanced outputs with 5402 and without affecting the tone. and it actually sounds really nice.

I couldn't run both boards from the same power transformer as it was making some noise and i am actually going recreate the SRPP tube stage without the pcb onboad power supply, 

My question is can one powersuply board handle 4 tubes or should i use 2 boards?

bernbrue

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #144 on: June 09, 2017, 01:09:01 AM »
The board is not the problem. Check if your power transformer delivers enough power. Heater should have around 2A.
Bernd

gaetan

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #145 on: June 09, 2017, 05:02:48 AM »
The board is not the problem. Check if your power transformer delivers enough power. Heater should have around 2A.
Bernd

it's rated 2.5, but to be honest i don't mind having 2 power trafo. I'll do more experiments.

What a fun project, thanks Bern!

gaetan

Re: [BUILD] The Rude Tube IVORY ====== Official build & support thread
« Reply #146 on: October 12, 2017, 02:53:30 PM »
Here is the machine, it took me a while to get it to sound the way i wanted and i finally found the right tweaks and it sounds insanely good.