Tube AND Pumpkin?
well, I did stay Tubehead, all these years, even if
on the other hand, why should I be Lone Sucker, refusing to indulge Audiophoolery urges and instincts?
slight digression, but - Tanka is result of coincidences
- Guy asked for something which he can put in fancy custom made wilder than 'Talian tube gadget box, and sell to suckers for big money
- recently I helped a friend to repair tube preamp and SS amp, for his friend; he sent me pics, tried to make sort of schematics, then I made functional schematics from those (sorted puzzzzlesssssssss and errors) ........ then did some analyzing and came with revised schematics and several necessary cures - not just some parts values but also wrongly dimensioned xformers in preamp and aaaargh! clueless errors in line stage
yeah, we know that Mediocrity Rulez.......... but Mediocre Mediocrity rulez even more
If being a sinner implies better sleep at nights I don’t have any problems with it.
Yesterday I did some a/b testing bypassing the iron pre and getting the signal straigh from the dac into the warbler, xa252 pop or cubbie3 and didn’t notice any difference at all.
My implementation of the ip implies some sinns too
So for me this stuff is really good!
I haven't been able to make any progress since I screwed up with the twister selector PCB, and selector. First, I lost the original one. Birdbox sent me a new one. Then I soldered the twister in the wrong position..... does anyone know the mouser part number for the twister and the cable connector? I am really done with this one.
@Jacruzer787
Rotary Switch
Cable Connector
I have a bunch of the 14 PIN headers, let me know if you need a couple.
Rotary Switch
Cable Connector
I have a bunch of the 14 PIN headers, let me know if you need a couple.
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ZM Omnisilly, forgot to take few pics yesterday, prior to giving it to my Guy for listening/evaluation of proof of concept for his future preamp
Soldered pair of HiNi Cinemags on small uni pcb, even mounted 3pin jumper pins for 6-12db selection and inserted them in between buffers and output
Then what I knew it'll be needed, due to longish wires from regs - tidied up local decoupling where was needed, it ends needing just 220n from rails to GND (+/-25V) at small pcbs containing mosfet CCS and mosfet (both part of tube governed buffer), to get rid of some fuzziness
Then again in workshop system to hear Da Iron Singing ......... wiiiiide green on my face .......... as alwayswhenever what I drew on back of napkin actually sings
Then
finding that I have intermittent crackle when I touch one of small heatsinks for mosfets - beauty of using dotsy uni pcbs - reminder for my self and all of you - when using desoldering gun blingy, normal thing when making errors - it leaves solder spray/whiskers, not being tricky when working on proper pcbs but with $heety ones it's hard to see residue; up to bench again, dismantle, clean, assemble again, up in system againeven broader green - will not bother with any damn measurements
working name is Tanka; damn, I should call it Seirḗn
was happy to hear there is no hum, xformers taken from shelves are biiig and old, and I half-expected to wrestle with them in some way or other, but sometimes my Fools-luck is even greater than usual
vol pot is some pro-series (conductive plastiK) Alps, 10Klog, separate shafts for channels; as far it goes with pots - for me all-the-same-good when conductive plastic is in case - TKD, Alps, P$G, Piher; speaking of resistive Vol. attenuator, I'm finding only relay switched resistor matrix better
here ya go, enough for little blingie
pic from previous big post and pic from Eagle, with tiny tidbits
Note - as I organized it for final product - one ECC88 is used per channel; in case of SE, both triode systems in bulb are connected in parallel (double xconductance, half noise, half Ri); in case of Bal, each triode in bulb operating own phase
Ah, fancy! Switching shunt volume control! And logic! Oh and LS jfet pads! I want!
not exactly shunt, at least not as Audiophoolery Pool see it - as one fixed resistor followed with variable shunt resistor ........
everything written on schematic, including most important facts - constant Rin and max deviation between steps; if that's not uniform, brain is puzzled, same as if you are walking uneven stairway
note - 64 steps is more than enough, but 128 ought to attract more attention
what's missing on schematic is final shunt resistor - 24K, that one placed as Gate - to - GND for JFet in buffer
Attachments
you were sort of asking about Compound buffer ....... and Turtle, so reply/quote is #1970
#1973 is quote to #1971, sort of denying "shunt volume control"
