I think we all get inspired when we see something very different, good looking and knowing there is a lot of work gone into it. Please, show-off.
Part assembled and part wired this UX-171-A 1920s tube (matched pairs) based amp is near completion. Regardless this is exactly how it will look when complete. There are no resistors or capacitors in the audio cct. a Hammond 124B nickel core inter-stage trannie couples to the power tube. Edcor 10W OPTs in the metal case. Bias is provided by 3 X 9V batteries and 230VHT by two step-down trannies on in reverse. The rec tube is a very old "80". PS filtering under the top plate (ply timber). The base will house the power trannies and is a 1940s wooden pot stand. The amp should produce 0.5W! I have named the amp "Intermezzo".
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INSPIRED!!!!
Well done!
not only it's well done but also ART...
i myself try to build the best possible amps in my abillity, i try to pay attention to all details. to me, i dont think building multiple amps with minimum efforts is exceptable.
Thank you all for your compliments. There is no thread at this moment for my design, I do not know if there is enough Interest to start a thread, so please report if you are interested.
Regarding building time: this is half a year building, but some years of designing different amp types to discover what works best, and after building; again tweaking and optimising the schematic to adjust the sound balance to fit in my system.
My main goal was to design an amp chassis and component layout that would give me the freedom to change the design without having to change or rebuild the chassis, as this is very time consuming. I use sub chassis plates where I mount the tube sockets on, so I can drop in any socket that exists.
If I want to experiment with the design I can now change it on a saturday afternoon and enjoy music the same evening
I however have learned that some design choices still return because they sound so good, like: using directly heated triodes, using interstages, usage of tantalum and carbon film resistors in the right spot. So the design changes at this stage are only to tune the sound or try some new NOS tubes when I find them.
I agree with you Tim; do it right otherwise you are wasting your time............
Regards,
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Hey, my favorite valve
Keep us posted on the results. Do you have different brands of 813 / QB2-250 to try?
Very nice!
I see some ECL82 in push-pull... a gas regulator and its 6AS7G pass tube... two beautiful magic eyes.. what are the other tubes?
Relly interesting!
I red wonders of this little tube (E/PL82): matched with E/PC86 as a preamp tube and in SE triode configuration can give the most beautiful 0,5w ever.
Or so it's stated on "high sensitive" a german book published about 11 years ago.
Can you share the scheme and your listening impressions?
Ciao!
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thanks!
Two pairs ECL82 in push pull, two EM71a magic eyes, ECC83 preamp double triode. 85A2 gas regulator as a voltage reference for another ECC83 running as a cascode error amplifier driving the grids of 6AS7G, both sections in parallel for a regulated PSU at 270volts 250mA
The pentode sections of the ECL82s are wired in ultralinear to a pair of Sowter 10W @ 15Hz OPTs (big for 10W to get the low end nice and flat), the triode sections of the ECL82s are running as a longtailed pair phase splitter.