pre amp tube grid resistor help

Started by makaze808, September 22, 2010, 10:23:36 AM

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makaze808

Hello.

Please see data sheet here

http://www.r-type.org/pdfs/dm160.pdf

On the page with the maximum and minimum values there is an entry for Rg    would this be as a grid leak resistor or grid stopper resistor.

Thanks.

~arph

I'd say grid leak. But it is a bit of an oddball tube. I'm interested  in any circuits you produce as I have got four of these tubes laying around to use as indicators in my echo project, but I haven't got around experimenting with them.

merlinb

This data sheet is more friendly:
http://www.mif.pg.gda.pl/homepages/frank/sheets/009/d/DM160.pdf

Rg appears to be the to be the combined grid-leak + grid stopper resistance. In an audio circuit though, I would ignore it and use what whatever you feel like.

makaze808

Ive just breadboarded two dm160's, 100k plate resistors, v1 has iinput cap, 1meg leak 33k stopper. 447n coupling into 100k stopper for v2. Feeding only 30v to the plates (shoul;d be 50-100) Problem is if I put in a v2 grid leak resistor then v2 stops working and no output. It works fine without a v2 grid leak.

Sound is very good for full chord overdrive (im feeding it into a 5 watt clean marshall. Very strong big chords ac/dc ish and very UK sounding. But the sound is not good for single note work, feels sort of too tight.

Any ideas on why the v2 grid leak may be causing loss of audio?

any ideas what may be causing to too tight sound?

It really likes being driven,muff, dr booogie, rangemaster, rat,  all very cool

The magic eye bit works slightly on v2 and is cool.

merlinb

Quote from: makaze808 on September 22, 2010, 12:46:48 PM
Any ideas on why the v2 grid leak may be causing loss of audio?
Would need a schem to answer that. You running the heaters in series?

makaze808