multi transformer preamp?

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pandatone
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multi transformer preamp?

Post by pandatone » Sun Nov 20, 2005 4:34 pm

so, i'm working away at my Gssl.
but my brain is already wandering now to new things that you can't get. and that i think would be interesting. i know people have done stuff like this. but of coarse i can't find it. and wondering where i should start looking.
i am interested in a preamp. that has switchable transformers. IE. like a switch that sends the singnal through various transformers. would i put them on the output? or input? realisticly, i dont' know anything. looking for a starting point.
i would think i would want to put them at the output. cause i would want to drive them as hard as possible.. so they'd be post gain?
what do you guys think?

panda

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soundguy
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Post by soundguy » Sun Nov 20, 2005 4:48 pm

panda, you should listen to a bunch of transformers before making assumptions about what you gain by "driving them hard" or other internet catch phrases. You could put several in a box with a logic switching circuit for the input as well as the output. Start off by purchasing a small pile of transformers and listening to them on the circuit you are building and then select the ones that are radically different enough to justify putting in the box together and then figure out the switching circuit for them. Totallly doable, no biggie. The kind of transformers you chose are going to be largely influenced by the sound of the circuit you build so you'd really IMO need to build something up and then listen to see what you like instead of figuring out the whole thing on paper first.

dave
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pandatone
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Post by pandatone » Sun Nov 20, 2005 6:03 pm

soundguy wrote:panda, you should listen to a bunch of transformers before making assumptions about what you gain by "driving them hard" or other internet catch phrases.

when you assume you make a ass out of you and me. i wasn't assuming on what i would gain. i was wondering if i would, if there was any benefit from putting them before or after a gain stage. i was wondering if putting them on the output would give me more control over tone. also thanks for calling me on some catch phrase i've never really heard of being a chatch phrase, other then, by you right then. i drive everything hard. [like preamp into preamp etc] i was just typing ideas out loud. knowing i could be wrong. thanks for making me feel like some kind of ass.. but....

otherwise your plan sounds like a solid one. testing transformers before i make a whole deal out of it. i guess i was hoping someone could point me to someplace i could read about what kind of circuit i would build to take the best advantage of the transformers.. there seem to be alot of transformerless design's out there.. and i honestly don't know enough to design my own circuit.

other then your opening statement, thanks for the rest of your post, i'll hunt down some transformers to start. and move this over to the prodigy forums i guess once i get to putting stuff together..

panda

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soundguy
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Post by soundguy » Sun Nov 20, 2005 6:27 pm

jeesh dude, take a chiill pill, Im trying to help you not make you feel like an ass.

some circuits will not drive a transformer at ALL let alone "hard". Some circuits can not drive the load presented by a transformer or will not do it well so it helps to listen to see if you are making things better or worse by adding transformers.

Often it is easier to drive a transformer "hard" on an input than it is on an output. This should be self evident to you since you like to put your preamps in series, but I guess I shouldnt assume that.

If your goal is distortion in the circuit that sounds cool you can check out what scott hamptone did with the jfet preamp that lots of folks around here built. configuring amplifiers like that is an easy way to get results. He also placed the mic pad after the input transformer, not before it for similar effect however, like I stated before, you need to listen to the transformers you intend to use as not all transformers will take the level so you should base your design around the parts you've auditioned not the other way around. Thats the way I would do it at least, I suppose there are many ways to shave a cat.

dave
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pandatone
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Post by pandatone » Sun Nov 20, 2005 6:56 pm

yeah, a hamptone is next once i get the funds back up.. i didn't know he did something different with his design, i am interested to see it.

yeah, to assume i know anything about how this stuff works is trouble. i've been pretty much latch key / plug n' play. just now getting to where i want to be able to control my sound completely. verse what other people [manufactures] thinks i want.

i was actually thinking that JLM audio j99 kit could be an interesting place to start. to get it without the transformers,, and try out various transformers instead of the "JLM 1:4 Input transformer" well, that one too.. [i also have a jensen JE 123-A sitting around. i don't have any docs for it though. =( ] then, once i've found one's i like.. to make some kind of switch to move the signal from like.. the 3 selects or whatever. but then the whole unit could be built around a solid preamp to start.

and i apologize if i jumped some on your post. your knownledge i think is indispensable. [the mixer you made is a feet of amazing skill, i hope is sounds killa] and your striaght honesty is a good thing. but sometime you start out a little ruff/heavy handed. i'm not asking for a chearing section. just information. cause i dont know what i'm talking about.. this is all new to me.

ps. any suggestion of transformers to check out [from anyone].. please let me know.. and i'll hunt for them..

panda

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Post by Shawn Simmons » Sun Nov 20, 2005 7:12 pm

There is someone making a pre-amp with switchable output transformers.

Go here: http://shadowhillsindustries.com/ Not the greatest website. There is a much better description at Vintage King.

shawn

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