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a green OTL, DIY?

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Posted on August 1, 2009 at 11:17:55
Montobo
Audiophile

Posts: 143
Location: Clemson, South Carolina
Joined: July 16, 2003
 O.K. In a sense, just kidding. I figure there is no such thing as a low power-consumption OTL. But how close could I come? Just asking. I am searching for a DIY OTL amp solution.

My system:

Super PAS/Van Alstine--his ultimate tweak of the Dynaco PAS 3. Decent and quiet enough.

medium small room

Lowther DX-3, 15 ohm. It is going into a Bob Brines LT-2000 with either BSC or Basszilla cross-over (top) and/or not (switch-able and as needed freq. adjustable) cross-over to Fitzmaurice horn sub. Sensitivity with BSC, 93 dB, this is Bob Brines figure, so it should be realistic rather than dreamy. Anyway, if I REALLY need more power on occasion, I've got a more powerful amp to switch to.

Strongly desire: DIY from a CLEAR schematic and (preferably) pictures/instructions/plans or
Desire: 6-8 watts, could settle for 3. I'm in an apartment and I would not call it huge (maybe medium)

Information/forum support (but not necessary, especially if other parameters are met)

OR, I could SETTLE for a kit (e.g. Transcendent SE), but green power? (uhhhh)

Strongly desire: as low power consumption as can be had given the situation and therefore might do better with PP--something like Transcendent T-16 but with lower power (say 1/3 or 1/4 output power ?) resulting in lower power consumption, preferably DIY rather than kit.

Skills: at the very least, decent soldering/construction/schematic and/or direction-following/computational skills and can cope with some theory but basically need to follow more than lead. I could probably build from a REALLY CLEAR schematic + decent picture(s), hopefully, to give a clue for layout. I am in science/engineering and do some fabrication and soldering and have assembled kits (and normally find them straight forward) and am willing to take on a challenge with fabrication, but I'm not an experienced DIY amp veteran.

I saw the Transcendent Cathode Follower which meets all the parameters (DIY option with plans, low power, affordable). This looks like the best bet BUT!! is not OTL, which I prefer.

Price: DIY under $1k preferred but could vary with the right solution. Still, I prefer under.

Current amp: Van Alstine FET-Valve Hybrid. It's a nice amp but I think something else would match better with the Lowther.

More information or clarification?
Thanks for your suggestions. Very much appreciated!!

another thought, posted on August 4, 2009 at 11:05:11
Ralph
Manufacturer

Posts: 1157
Location: Minnesota
Joined: April 24, 2002
Contributor
  Since: April 1, 2002
 If you can put 2 Lowthers in series in a single cabinet, you could drive them easily with just a pair of 6AS7s per channel.

SE-OTL, posted on August 4, 2009 at 00:16:00
Dr. Philosophy
Audiophile

Posts: 540
Joined: June 4, 2002
 You mentioned the Transcendent Sound SE-OTL, but I wasn't whether you realized that: 1) It is - I think - the lowest power consuming tube OTL out there, and 2) likes, as almost all OTLs do, high impedance speakers such your Lowthers.

would work with my speakers (output 3W). 230 watt consumption., posted on August 4, 2009 at 17:06:37
Montobo
Audiophile

Posts: 143
Location: Clemson, South Carolina
Joined: July 16, 2003
 Thank you.
RE: a green OTL, DIY?, posted on August 1, 2009 at 19:09:04
Slick
Audiophile

Posts: 308
Location: Maryland
Joined: April 10, 2002
 Transistors probably fit the "green" requirement best. They are OTL after all. The large tubes needed in an OTL of even a few watts will have tremendous heater consumption as well as large standing plate currents. The "T" amps are digital amps with very low consumption, you may wish to check into those.

A compromise would be building a Moskido. That is an Aikido tube driver stage operating into a MOSFET output stage operated in Class A. The folks building the things have lots of nice things to say about the amps. Many versions have been built with varying types of output devices and at widely varying output levels.

Because the output stage still operates Class A, it is not as green as an AB amp or a digital amp. But it may be an acceptable compromise.

There is an extensive thread about the Moskido on the DIY Audio board.

Stuart


"My God, it's full of stars"
Thoughtful reply. Never heard of but will look into. Thanks. nt, posted on August 2, 2009 at 06:12:11
Montobo
Audiophile

Posts: 143
Location: Clemson, South Carolina
Joined: July 16, 2003
 nt

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