Understood (I think 
. After about an hour we're at 0.192V-ish (seems to be climbing slowly over time?)... with offset around .04V... I'm not able to adjust Iq lower at all—at the bottom of the twiddler range...which is were it's been from cold start....more or less—self biasing!
Sinks as measured by controversial laser gadget around 130F, less on SIT sink... so, in range....mosfet is on ceramic pad with goop all round. Can easily hold my hand on sinks... and seems about the same or a tad less hot than J2Babel...
We know you always do your best.
Oh—rails are DIY PSU 25vdc unloaded…
. After about an hour we're at 0.192V-ish (seems to be climbing slowly over time?)... with offset around .04V... I'm not able to adjust Iq lower at all—at the bottom of the twiddler range...which is were it's been from cold start....more or less—self biasing!Sinks as measured by controversial laser gadget around 130F, less on SIT sink... so, in range....mosfet is on ceramic pad with goop all round. Can easily hold my hand on sinks... and seems about the same or a tad less hot than J2Babel...
We know you always do your best.
Oh—rails are DIY PSU 25vdc unloaded…
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that was my brainfart
I presumed you wanted higher Iq, and I meant it, made a typo while thinking that you need lower value of shifter resistor for that (higher Iq)
anyhow, you managed
Zero worries ZM…
The UGS of the SITs are the factor here? Somebody ran into a similar issue (@rhthatcher ?)… Think it was Sissy though… Might be gettin ahead of myself.. but just thinking about that Sissy (42)… since these monos are the SIT playground at the moment…
The UGS of the SITs are the factor here? Somebody ran into a similar issue (@rhthatcher ?)… Think it was Sissy though… Might be gettin ahead of myself.. but just thinking about that Sissy (42)… since these monos are the SIT playground at the moment…
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with this last and final derivation of biasing circ, practically any Ugs SIT can be used, with slight tweak of level shifter resistor value
and this biasing circ is now implemented in most of my amps, ZM being Square Law OS Fetishist
(if Berserker Pucks are tamed, anything can be tamed; only ZM can't be tamed
)
and this biasing circ is now implemented in most of my amps, ZM being Square Law OS Fetishist
(if Berserker Pucks are tamed, anything can be tamed; only ZM can't be tamed
)
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@e_fortier
Thanks! Yes, fully custom metal work, laser cut from my files—then tap and assemble etc...sinks from Modushop via the DIYaudio store...need to finish the fronts which I will make out of multiply w/ high gloss black front layer (just a style preference, could be made from anything)... usually I've been using a fancy metal Apem latching switch for accessible front power (kid likes to turn on the amps with toes!)...but they have doubled in price for some reason... will do a recessed flip toggle (see pic, more work, on a bracket I designed).... may not be fully finished for a week or so...
Thanks! Yes, fully custom metal work, laser cut from my files—then tap and assemble etc...sinks from Modushop via the DIYaudio store...need to finish the fronts which I will make out of multiply w/ high gloss black front layer (just a style preference, could be made from anything)... usually I've been using a fancy metal Apem latching switch for accessible front power (kid likes to turn on the amps with toes!)...but they have doubled in price for some reason... will do a recessed flip toggle (see pic, more work, on a bracket I designed).... may not be fully finished for a week or so...
Attachments
Well... these guys are in play! J2/Babelness ejected!
Not going to wax poetic about sound yet, well, maybe. I'm always surprised when interviewing amps—I forget how much fun it is... and really I just get totally inspired to find a space for another system. Haven't done any "critical" listening yet.... Hi-res digital sounds bloody fantastic as we just have some Bill Evans on in the background. Lots of tinkling highs—that I'm not sure I'm recognizing/remembering—there's definitely a certain new feeling clarity—and when I think "where's the bottom end?" it hits! Fantastic. I always know more when I go back to the previous longer term amps....Here's a new thing... "sound" changing as the amps heat up.... don't recall "witnessing" that in the past will all the previous builds... COOL! For the better of course...
The plan now is—over the next month—drop the rare parts into the J2/babelfish—rotate them in—swap Scryer for SissySIT (42)... then I might know some stuff. Or I'm building an addition on the house...... !
Thanks! ZM!
Not going to wax poetic about sound yet, well, maybe. I'm always surprised when interviewing amps—I forget how much fun it is... and really I just get totally inspired to find a space for another system. Haven't done any "critical" listening yet.... Hi-res digital sounds bloody fantastic as we just have some Bill Evans on in the background. Lots of tinkling highs—that I'm not sure I'm recognizing/remembering—there's definitely a certain new feeling clarity—and when I think "where's the bottom end?" it hits! Fantastic. I always know more when I go back to the previous longer term amps....Here's a new thing... "sound" changing as the amps heat up.... don't recall "witnessing" that in the past will all the previous builds... COOL! For the better of course...
The plan now is—over the next month—drop the rare parts into the J2/babelfish—rotate them in—swap Scryer for SissySIT (42)... then I might know some stuff. Or I'm building an addition on the house...... !
Thanks! ZM!
I really like these amps! A friend, who's followed my journey, and who has some technical listening skills—commented that these amps are "very relaxed" and "easy to listen to". I've been thinking on that... it's a solid observation. There's nothing missing here. Also, I believe I have experienced "more" at lower volumes than past amps... I will be thinking on this as we cycle them in and out...
Hi,
after an 8 month break, in which I concentrated almost exclusively on loudspeaker construction and class D, and where one heat wave followed another 🥵, where DIY was hardly even an option, the cooler season is finally here again and - after I've already completely dismantled it - my Scryer is almost finished. All that's missing is switching it on
but I don't have a fuse holder, I've been looking for it for half an hour, so it'll have to be switched on next week, I'm really excited.
after an 8 month break, in which I concentrated almost exclusively on loudspeaker construction and class D, and where one heat wave followed another 🥵, where DIY was hardly even an option, the cooler season is finally here again and - after I've already completely dismantled it - my Scryer is almost finished. All that's missing is switching it on
but I don't have a fuse holder, I've been looking for it for half an hour, so it'll have to be switched on next week, I'm really excited.
@Plott - Beautiful!
I keep some of these around... (or similar)... are you using something like these?
https://www.harfington.com/products...rBUa_76YelG4xH_CEO2MwgCM10SE1yW4aAjagEALw_wcB
I keep some of these around... (or similar)... are you using something like these?
https://www.harfington.com/products...rBUa_76YelG4xH_CEO2MwgCM10SE1yW4aAjagEALw_wcB