Holy micorphonic batman!

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

I just completed an experimental 'preamp' to try out various DHT tubes. Since I 'must' have tone controls, the circuit uses a 56 into a Baxendal tone circuit, followed by one of the following driver tubes: 112A (Globe), 46 (triode connected), 26 or 31. I placed a switch around the various driver tubes and set the volume controls on each such that the gain was identical, regardless of which driver tube was selected.
Well, let me tell you, these suckers are microphonic, the 112A being the worst and the 31 the best. As far as sound (which was the point of the experiment), it was pretty much impossible to tell the difference (they all kinda sucked - too 'bright' for my old JBL speakers), although I slightly prefered the 26 and 31 to the 112A and 46.
What is the experience of others using DHT tubes in a preamp application? I'm about ready to return to my 6SL7/6SN7/EF86 (triode connected) preamp - it does sound better.
P.S. All filaments were supplied by batteries, and I used fixed bias (from a 45 volt battery) on all tubes.

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Topic - Holy micorphonic batman! - mikeyb 09:13:01 10/31/05 (3)

Re: Holy micorphonic batman! - cjr888 03:46:01 11/01/05 (0)

Re: Holy micorphonic batman! - Caucasian Blackplate 17:02:38 10/31/05 (0)

Re: Holy micorphonic batman! - zacster 12:30:21 10/31/05 (0)

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