Dht Guitar Amps

[fergs1]

Greetings Ladies and Gentlemen, well I haven't been around for a while because of a broken computer and low funds to fix it.
Has anyone had a go of making a SE guitar amp utlilzing DHTS such as 300b 2A3 etc I can't see anything on the net apart from some obscure reference to a 300b guitar amp that alowed more of your playing come through( is this stuff legal) but not much else.
Any ideas, sightings opinions most welcome

peace and goodwill fergs

[Makofoed-6sn7]

Hi Fergs,

I have been toying a little with the idea, but you must remember that a guitar amplifier is given a much more rough treathment that HiFi amplifiers. DHT are generally more fragile than inderectly heated tubes.
You can see it if you look at a 300B, then a 6L6 or other powerpentodes/tetrodes.

So it would be a very costly project. The tubes are expensive and will not survive long in a guitar amp.

Sorry, I don't think it worth it. It would have been a fun project, but still.

Best regards,

Magnus

[Tweeker]

Keep the roadies away from it, the filament is fragile (in the context of mobile amps).

[Geek]

Yup! Been done successfully in PP

http://www.straubamps.com/tt.html

[fergs1]

Good to see some replies, I know the fragile nature of 300bs as I have them in my hifi amp.I'm thinking of a project that is mainly for home use, and as I've never made a shekel in all the years I've played the game I've never had to worry about paying roadies to trash my gear..
The unique nature of dht sound wise would have to transpose to guitar amps, the question being is it a good sound for guitar? Someone must have experience here!Where art thou!
peace and goodwill fergs

[dsavitsk]

Gordon at Wavelength Audio make DHT guitar amps: http://www.guitar-engines.com/index.html

The usual comment is that they are great jazz amp, but not so great rock amps. Never heard one, so I have no idea if it is true or not. I also always have wanted to try this, but I have not gotten around to it yet. Someday.

[tubelab.com]

I routinely plug my ADA MP-1 guitar preamp into every amplifier that I build. I play them gently and cleanly, and then I crank them to at least 12, 10 or even 11 is for wimps! This is one of my typical torture tests to find the weak links in any design. I have played guitar through 45's, 2A3's, 300B's, 845's and even the monster 833A's. All amps were SE designs.

The DHT's have a distinctive clean sound that would be excellent for an acoustic, or hollow body electric. I would love to hear a 12 string through a DHT amp. When cranked to 11 the DHT will not get as nasty as a pentode amp. When I dial up my best overdriven Hendrix preset on the ADA the big DHT amps sound great. I believe that most of the difference in the sound is due to the fact that all of the DHT amps were triodes, and most of my SE guitar amps were pentode, or switchable triode - UL - pentode designs. I find that pentode mode is best for that cranked to 12 sound (more gain in the output stage).

I have not yet done any purpose built DHT guitar amps, but it is on my (long) list of projects. I have a bunch of VT225 DH pentodes. Maybe I could use them.

See the web page for details of a 200 watt DHT guitar amp test. You will see where my avatar came from.

http://www.tubelab.com/833SE.htm

[Geek]

Hi Tubelab,

Have you ever had to "use" that blast shield over the amp?

Cheers!

[tubelab.com]

Whenever I power up something new I have a fire extinguisher handy and I isolate myself from the device under test. The extent of the isolation depends on the "extremeness" of the experiment. It is usually just 6 feet of distance on a "normal" amp. Everything is powered off of the same circuit which has two "kill switches" in case things get out of hand.

The 833A amp was considered "most extreme" due to the very high voltages involved and the obvious use of underinsulated wiring. This was the reason for the plexiglass shield. That experiment was uneventful except for the "what was that noise" phone calls.

There have been a few incidents in the 30 years that I have had that lab. One involved an expolding electrolytic in a power supply from an old PC that left fragments in the ceiling. And a few exploding mosfets in a SMPS powered by a car battery. These incidents and a few others have led to the overcautious attitude that I use now.

[hcstraub]

Originally posted by Geek
Yup! Been done successfully in PP

http://www.straubamps.com/tt.html

Thanks for noticing.....

I was getting a lot of requests for a full sounding guitar amp at home playing levels. Most of my amps go to middle age folks who like nice cabinets, want some wife acceptance factor and play at home. They wanted a full out tube distortion sound in an amp they could crank at home and not **** off the neighbors. A 2A3 guitar amp in push/pull hit that sweet spot of power and unlike el84's wasn't bright and brittle sounding. I am thrilled with how it turned out, especially with the extra gain boost it sounds like a monster at pretty doable levels.