Experiments (Transformer content)

Kane17

New member
Ok So I've had my Vox Tonelab SE for a while. Has weathered the honeymoon phaze for me and works for all my different musical applications.

I just got home from a very long trip and the good wife has bought me an amp as a homecoming present. woot good for wife...

It's another SS head..hmmm..

So just going to experiment the heck away with this. Not going to be totally letdown if I hurt it a little but I'm trying to get enough info before I do something that is guaranteed to fail...


I've been reading a lot of how tube amps intereact with the output transformer and the speakers.

The idea is to emulate this somehow.

I have a mic tube preamp also and it really warms up the signal when its pushed to clipping levels.

Idea #1

Place the preamp in the loop with its gain hi enough to clip.
I know this can be bad because the output signal will be much higher than the power section is expecting. So in order to dampen it I was thinking of placing a step down tranny between the preamp and the power section..(will compare normal strength of signal compared to output of clipped preamp before I determine which ratio I will use for a transformer)

I've so far only had experience with isolation transformers, is there any dangers or concerns to be taken into account with step up/downs? I hear lots of stories of these dying or hurting the amps because something wasn't right..

Idea #2

Simply taking the preamp and a transformer from the first idea and adding a small speaker after the transformer

This would essentially provide a small inexpensive tube amp all in the loop..my only questions would be how to make sure the signal coming from the final component would be correct enough to properly drive the power section.

The general idea is to capture the relationship between the trany and the speaker as opposed to the first idea where it would just go from the trany to the powersection which probably won't mimic all the impedence changes that occur in a real amp.


Idea #3

Just since it seems almost too obvious...Taking a large isolation transformer and placing it between the amp output and the cabinet... I know tube amps generally use trannys for impedence matching but if the transformer has an effect on the signal, why not use one anyways?? I'm guessing amp manufacturers don't do this since it could be an unnessesary danger to the amp when its not electronicly necessary...or maybe its just not special and not worth putting on a SS amp anyways. My real question here is, doing this should not blow anything up, yes?



Good thing is that the amps preamp has its own volume to feed the loop and the amp also has a master. So I know I'll have a lot of control over whats driving what and at what level...


Before someone lectures me on how this will never make it sound like a real amp, Its ok.. I know ;) I'm just doing this for fun..kind of like overclocking a 10 year old computer. Just want to fire it up and see what I can get out of this amp.


All I really want to know is if I'm going to start my house on fire..
 
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Re: Experiments (Transformer content)

idea 1: Just use a potentiometer to attenuate if it doesn't already have a level control for the output. Atransformer is just going to introduce noise and isn't necessary at this power level.

idea 2: You got enough power to drive a set of headphones...maybe.

idea 3: The transformer will likely just cause a noise issue and not add any warmth. Solid state designs that are transformer coupled are collector driven while direct or capacitive coupled designs are emmiter driven. Deliberate losses designed into the transformer give the warm character. The possiblity of finding a 1:1 transformer with the right type of losses built in are pretty slim and then getting it to react properly with a current source output would be another trick.

Stick with idea 1.
 
Re: Experiments (Transformer content)

idea 2: You got enough power to drive a set of headphones...maybe.


Thats really all I was going to put there. Just a single (maybe large for a headphone) speaker. nothing that I would even hear over the amps fan. Just something to give the line a little more reactivity.

...However the whole point of that was in hopes that it would react nicely with the transformer which you don't seem to think is such a great plan soooo will probably just stick to the tube preamp with a pot and call it a day.
 
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