Re: tube preamp problem (SOLVED)

[simonsez]

How to fix this? This is from my red47 diy with jensen DI transformer for input and edcor 15k:600 output transformer.
When i switch the sine wave to square wave, the wave looks bouncy for a second, then steady.

Thanks,

Simon

 

[mich]

Thats not a problem....- thats a good bass response ;D

maybe a zobel combo on the output tx

 

[CJ]

that looks more like a freq plot where the guy had the scope on ac instead of dc which gives an artificial bass bump,

you mean the amp flat lines like a heart victim or are you sweeping all freqs with the sq wave?

for sq wave test you want to inject 1000 hz sq wave and look for ringing,

 

[simonsez]

That graph was from RMAA test.
About square wave, i think it's look good, no overshoot except the wave was bounce for a second when i switch from sine to square.
It have regulated PSU and DC filament supply, so i think it's not PSU problem.
I did that in protools with 1khz tone.

 

[okgb]

How does it sound ?

 

[simonsez]

It just sound great, silky nice sound. It give strong nice character to vocal. But i still curious with the scope test, still workin on it.
Btw, this is my red picture, i mean THE RED REDD ONE 

Power transformer position for minimal noise.

Not pretty inside.. :-[

 

[fazer]

Nice looking build. 

Are you sure thats not the settling time of the oscillator at Low frequency.  Thats pretty common for a low distortion bridge oscillator.

Michael

 

[simonsez]

Nice looking build. 

Are you sure thats not the settling time of the oscillator at Low frequency.  Thats pretty common for a low distortion bridge oscillator.

Michael

What do you mean by that? how do i know that i have low freq osc.? and how to fix it?

 

[ruffrecords]

To make sure it is not the test equipment you should try sending the test signal direct from Protools to the scope just to make sure the effect IS produced by the REDD47.

Cheers

Ian

 

[simonsez]

To make sure it is not the test equipment you should try sending the test signal direct from Protools to the scope just to make sure the effect IS produced by the REDD47.

Cheers

Ian

Yes. i did that, but it seems fine. i'm using software scope (plugins)  :-[ . Btw i feed this redd from low level line out with -20 input pad position., right now i don't have DI box  in my hand...opss..my be i should try feed signal to DI input...can i? no? 

 

[CJ]

you can do a freq plot with two voltmeters, one on input, one  on output, mabe not good to 100 k hertz, but good to 20 hertz no problem,

or just one meter on the output if you are sure about the regulation of your generator,

 

[simonsez]

Well, i think the problem is gone, simply putting a resistor across secondary OT, both problem is gone...

I'm happy now...

Thanks guys..