Nice design, altough the picture is a little unclear.
I can see that you use a small tube (ECC83 ?) and a larger one (12BH7 or 6N6P ?) in front of the 2 6C33C-B's. Maybe Andrea Ciuffoli's design ?
Could you share more pictures and some information about your OTL's ?
I am also planning to build some OTL's with the 6C33C-B's, have all the materials only not the time (yet).
I can see that you use a small tube (ECC83 ?) and a larger one (12BH7 or 6N6P ?) in front of the 2 6C33C-B's. Maybe Andrea Ciuffoli's design ?
Could you share more pictures and some information about your OTL's ?
I am also planning to build some OTL's with the 6C33C-B's, have all the materials only not the time (yet).
the small first tube it s ecc82 the secont it s spliter ecc182. the desing is Andrea Giufolli. Very nice clear sound!!! more fotos in a few days. sorry i dont know good english.
Congratulations!
There is something magical about OTL amps, something just a bit special!
During my experience with the 6C33c-B its very important to burn these in most carefully to avoid early failures.
Heaters only for 24 hours.
Heaters and supply to plate to draw 600mA for three hours. (Connect G1 to Cathode, set current by voltage across tube,--maybe use a light-bulb as current limiter)
Set bias after 1/2 hour of operation. Tubes do not thermally stabilise until after 20 mins after +B switch on...
Make sure the heater-pins are cleaned carefully, and keep dissipation below 40W per tube, to prevent socket to heater-pin high resistance connections...
--After this, you'll find the tube reasonably stable, and will last a long time...
There is something magical about OTL amps, something just a bit special!
During my experience with the 6C33c-B its very important to burn these in most carefully to avoid early failures.
Heaters only for 24 hours.
Heaters and supply to plate to draw 600mA for three hours. (Connect G1 to Cathode, set current by voltage across tube,--maybe use a light-bulb as current limiter)
Set bias after 1/2 hour of operation. Tubes do not thermally stabilise until after 20 mins after +B switch on...
Make sure the heater-pins are cleaned carefully, and keep dissipation below 40W per tube, to prevent socket to heater-pin high resistance connections...
--After this, you'll find the tube reasonably stable, and will last a long time...
generally the OTL design, much to the discontent of some people here, is superior only because of the lack of the output transformer but, my god, that is one hell of a big difference....
only drawback is power but you can go wild by using a large series of output tubes, lower your output impedance and cook your souvlaki too....
only drawback is power but you can go wild by using a large series of output tubes, lower your output impedance and cook your souvlaki too....
Very nice work. I bet it sounds great too. I am collecting parts for a 6C33C OTL and was planning on building Tim Mellow's design, but now I will have to take a good look at this design. I've not seen it before.
Great looking amp!!!
Great looking amp!!!
Cool.
I'm planning an OTL too.
Was thinking of the M-60 design but with 6080 tubes.
Could the 6080 (280 Rp) be used in Andrea Ciuffoli's? What would the output impedance be with 4 per channel?
Power supplies are much easier than the M-60.
I'm planning an OTL too.
Was thinking of the M-60 design but with 6080 tubes.
Could the 6080 (280 Rp) be used in Andrea Ciuffoli's? What would the output impedance be with 4 per channel?
Power supplies are much easier than the M-60.
I see Ciuffoli's design is a futterman style.
Is he reducing output impedance using the feedback circuit?
also the E182CC could be sub for 5687.
Is he reducing output impedance using the feedback circuit?
also the E182CC could be sub for 5687.
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Great work!
How does it sound? I own a 6C33C SE with output transformers and I was curious about the differences? Anyone compared the two types?
How does it sound? I own a 6C33C SE with output transformers and I was curious about the differences? Anyone compared the two types?
It's an inverted Futterman design, the output impedance is ~11ohm with 2 6C33C tubes, (the output impedance is as for 2 cathode followers in parallel (Rp/2*(1+µ). This is then reduced further by global feedback
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