Show us your flea-watts amps!

Bottlehead row (5 years after my last pic of my amps). There's also some Schitt there...
 

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May as well post my Bolide project here:

View attachment 1047731

The Bolide low-voltage SET breadboard develops about 1.5W output using $4 worth of tubes from the dollar bin at ESRC, and a $12 OPT, operating on a 96V B+ rail that comes from a pair of low-cost 48V switch-mode power supply modules. It sounds good, but I haven't convinced myself that it's worth committing to a complete chassis build. I'll attach the amplifier schematic below. Whaddya think? Is there any interest in low-voltage flea power designs like this?
Old posting answer I know, but this is a really clever design! the designer had to choose tubes with the same heater current series rating, yet have enough flexibility to work as a power amp with drivers.
One question though, if it runs from +/- 96v, don't you need four +48v SMPS's?
 
Very nice! Unlike the chassis plate. I built one of these. I've been very happy with it. What did you bias your output tubes at?

Running them at 65mA with a B+ at about 380V if I recall. It is whisper quiet even through my 96dB bookshelves but add a source and it drives my less efficient Genesis II+ (88.5dB efficiency) really well.
 
Running them at 65mA with a B+ at about 380V if I recall. It is whisper quiet even through my 96dB bookshelves but add a source and it drives my less efficient Genesis II+ (88.5dB efficiency) really well.
That's what everyone says, me included. They are very quiet. I have mine biased at 60ma. Other than mine, yours is the only other one with a base that tall that I've seen. Nice looking amp!
 
That's what everyone says, me included. They are very quiet. I have mine biased at 60ma. Other than mine, yours is the only other one with a base that tall that I've seen. Nice looking amp!

Thanks.

I run a fan underneath, it's designed for cooling PS4's I think but it sits on rubber feet and runs so quietly I need to put my ear to the base of the amp to see if it is on. The airflow helps keep the whole thing cool as they do have a tendency to run hot especially the mosfets.
 
Old posting answer I know, but this is a really clever design! the designer had to choose tubes with the same heater current series rating, yet have enough flexibility to work as a power amp with drivers.
One question though, if it runs from +/- 96v, don't you need four +48v SMPS's?
My original intention was to use a conventional power supply circuit for the low-current -96V rail. I never did build that amp design into a chassis, so I don't have a final power supply circuit design to show. The breadboard was always operated from benchtop PSUs.
 
Thanks.

I run a fan underneath, it's designed for cooling PS4's I think but it sits on rubber feet and runs so quietly I need to put my ear to the base of the amp to see if it is on. The airflow helps keep the whole thing cool as they do have a tendency to run hot especially the mosfets.
That's one of the reasons I built the base so deep. I also have vents on the sides near the top. I used a huge TO-220 heatsink for the double regulator mounting it to the top plate off the board. My Avatar is the one I built. Yours is the nicest I've seen yet. The wooden knobs are a nice touch.
 
Modified chi-fi SEP. Sounds great and dead quiet. Replaced some of the cheaper components and some that seemed out of spec, but just the chassis, xformers and two psvane el34s were worth the money. Probably 8wpc so maybe not quite flea.

Plus the Bluetooth module was a nice bonus.A9B5659B-1382-4665-A45B-FB054E05C1C2.jpeg
 
I guess this would pass as a flea watt amp. It's a headphone amp with driver and output tubes complete with output transformers. The impedance is selectable from 16 ohm to 600 ohm. It puts out 1.2 watts into 16 ohms.
If I had some 16 ohm speakers I would hook them up at see how it sounds.
IMG_20190313_110303.jpg
 
That's one of the reasons I built the base so deep. I also have vents on the sides near the top. I used a huge TO-220 heatsink for the double regulator mounting it to the top plate off the board. My Avatar is the one I built. Yours is the nicest I've seen yet. The wooden knobs are a nice touch.

Friend of mine made the box and the knobs from walnut. He also made the plinth for the TT from plyboo; he cursed me for weeks after :) That stuff is tough to work!! Apparently ;).
 
Friend of mine made the box and the knobs from walnut. He also made the plinth for the TT from plyboo; he cursed me for weeks after :) That stuff is tough to work!! Apparently ;).
Yup. I've built a lot of custom home installed book shelves and wall units using Oak and some walnut. They are hard woods. I've dulled a few saw and planer blades. My favorite is having to drill holes for finishing nails. :D I wimped out and used Maple.
 
Thanks to @opnly bafld , I own this beaut, a Dennis Had INSPIRE Universal SET amp:

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Tried it with various tubes, and from what I currently have available in conjunction with what I'm powering (some modded Altec 9844's), I seem to have settled on the original Gold Lion KT88's plus a Tung-Sol 6SU7GTY and a Mullard 5AR4. I do need to try the 6F6's pictured above again, when I can get a preamp hooked up to give me more input voltage. Next purchase will be some KT150's, though, which max the amp out at about 8Wpc.
 
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