In Reply to: Re: Looking for all-DHT parafeed 2A3 amp ideas posted by gluca on April 13, 2007 at 16:43:39:
I've now tried 112A into 2a3 as the last two stages in my amp, transformer coupled. when I use 3a5 mu=15 as first stage there's adequate volume. when I use 1G4 (mu=9) as first stage, sound is better but it's only just loud enough, with volume control just under max. My speakers are Monacor AL130, about 89db sensitive. Looks like a three stage DHT setup - whether you put the first stage in the amp or the preamp - is possible but requires some thought and planning.for more volume, it would be possible to use a higher mu valve as driver. about the only DHT that could do this is the 1J6. Or revert to an IHT tube like the 2C22 to get a mu of 20. It would be possible to use 4 stages and direct couple two of them. My feeling is to use a really good DHT for the first stage, and maybe experiment with the driver. there are also some output tubes with higher mu than 2a3.
Sound I'm getting is very smooth and detailed, with orchestral instruments clearly audible in the mix and bright delicate treble.
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Follow Ups
- 3 stage DHT update - andy evans 05:33:30 04/16/07 (0)