Transformer Amps

[Definity]

Hi, now im kinda new to electronic done a basic course on it at college a few years back and kinda would mind building my own pre amp for a mic or instrument. i was reading about transformer amps and they seam pretty simple to build also i know that they sound nice and the amplifier i wanted to buy (but cant cos of lack of 1000 GBP) has a input and output transformer in. so i was thinking mabey building one. not looking for something super more clean sounding. any of you guys know any simple projects that are made from transformers? i dont mind using transistors a few but i dont want to go over board.
thanks!!!


P.S i think i need about 80dB Gain if thats possible!

[Steve Eddy]

80dB of gain? That's an awful lot. Can you be a bit more specific as to what your application is?

se

[Artie]

Originally Posted by Steve Eddy

80dB of gain? That's an awful lot.

Thats what I was thinking. That would equate to approximately 18.5 volts out of a Shure SM-58.

[Definity]

Originally Posted by Steve Eddy

80dB of gain? That's an awful lot. Can you be a bit more specific as to what your application is?

se

whops i meant 60dB sorry! im using it wither for guitar or a mic SE2200. and im using it for recording so i need a decent level hence also why i want it to be nice and clean sounding EG no fuzz or noise, and when i mean clean i mean adding analog warmth/color to the signal is fine just not noise or fuzz!
Thanks!

[AndrewT]

Originally Posted by Artie

Thats what I was thinking. That would equate to approximately 18.5 volts out of a Shure SM-58.

what's wrong with that as a peak output?
A 5534 on +-21.5Vdc would have a peak output that is even higher and we use the spare as overhead for extreme transients and generally stay clear of the increasing distortion that usually arrives in the top 10dB of the output voltage range.

[Definity]

80 would be ncie fro the head room if needed but i would need around 60/70 since im planning on getting an SM7b and they need a lot of gain. so any simple diagrams that are transformer freindly?

[Artie]

Nothing wrong per se, just wanted to make sure he knew the level. But, wouldn't that level of gain potentially increase the noise floor?

[Steve Eddy]

Originally Posted by Definity

whops i meant 60dB sorry! im using it wither for guitar or a mic SE2200. and im using it for recording so i need a decent level hence also why i want it to be nice and clean sounding EG no fuzz or noise, and when i mean clean i mean adding analog warmth/color to the signal is fine just not noise or fuzz!
Thanks!

You're not going to find a microphone transformer out there with 60dB of gain. 20dB sure. But not 60dB. Also, such transformers wouldn't be suitable for guitar. The output impedance from the pickups is much too high.

se

[Artie]

I may have been more off base than I thought. The Jensen Mic circuit provides 74db of gain. I guess 80 isn't that unusual. (I know the OP restated 60db.)

[Steve Eddy]

Originally Posted by Artie

I may have been more off base than I thought. The Jensen Mic circuit provides 74db of gain. I guess 80 isn't that unusual. (I know the OP restated 60db.)

Yeah, though keep in mind that 80dB is twice as much gain as 74dB.

Also, I was under the impression that the OP was wanting to get all that gain from a transformer.

se