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Vintage threads from the first ten years
| previous: ken Klaus, I usually detect grid curren... -- 7/2/1999 12:52 PM |  |
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Re: preamp design ruminations
 7/2/1999 9:24 PM |
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Terry | Re: preamp design ruminations Hi Ken, I had basically the same question as Klaus asked about the grid so I want to thank you also. Sounds like a quick and simple procedure and I will have to try it out soon. I want to let everyone know on this thread that I have been reading it the last couple of days with much interest. I also have a little four stage preamp on my workbench that I tinker with from time to time. Haven't messed with it lately but have to get back to it. Just for kicks I'm even using a transformerless power supply and am extra careful with it. I have had all stages maxed out and I have let a stage or two draw very little current. I have spent hours tweaking different values of coupling caps, bypass caps and some resistors. I had also installed pots for each of the four cathodes and what a difference it makes to tweak those pots. Mainly using 12AX7's but tried 12AU7's. Someone further up had mentioned someone else's idea was to not let any stage draw little or no current. Well, my experience has been that by not maxing out each and every stage you get more clarity overall. Maxed out and it all sounds very rich like a soup with no broth. Each to his own taste and that's what it's all about I suppose. Also when I go to small coupling caps the sound is not as warm to me, yet too big and then it's too bassy. But it's a balancing act between small to large coupling cap and little or no bypass caps to large bypass caps along with tweaking the cathode resistance. Just sooo many variables sit ain't even funny. Also how about some positive or negative local type feedback between stages. I've heard of others that didn't like using series resistance so there are some options to a point. Anyway, we need more posts or threads like this one. There's a lot room for experimentation and coming up with one's own unique sound. Also, the guitar we're using, the speakers, power amp etc., all play a part in the overall sound. (we've heard this over and over but it's true) I believe that a total sound package would be to fine tune all components and instruments as a whole. Then your buddy can come along and plug his axe into it and you can laugh while he sounds like crap. Just kidding, but that does seem to happen at times and we just scratch our heads and wonder why. My intent was to make something just for my use for direct recording more than anything. I wanted to go from fairly clean to some nice smooth somewhat compressed distortion, not overly done. So far I have had some pretty good success but I keep tweaking and going back to square one because I don't know when to be satisfied. Sorry for the length of this post. Just want to say in closing that because of all you guys I have found a renewed interest in my little project and this July 4th weekend I hope to spend a little precious time indulging myself once again. Thanks to each and everyone and have a great 4th! Terry |
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| Andrew Hi, |