another issue covered somewhere in front ...... C3 is in series with R13 , and that RC cell used only for Edcor (be it M25 or Sissy, so applicable to both)
to save you few mm of solder wire ( in case you need it) , I presoldered SMD C3 , counting that you'll skip R13 if there is no Edcor
so , yes , leave C3 in , it's hanging invisible
🙂
to save you few mm of solder wire ( in case you need it) , I presoldered SMD C3 , counting that you'll skip R13 if there is no Edcor
so , yes , leave C3 in , it's hanging invisible
🙂
What about tiny white caps? still searching schematic for them. Better check M25 schematic, must belong there, but not finding place yet on board.
I Think I've been staring through magnifier too long today, time to rest eyes!
Tiny writing on them says 22K.....maybe a resistor. the search continues.
Ahh, I think it is for use with Borbly buffer maybe?
Russellc
I Think I've been staring through magnifier too long today, time to rest eyes!
Tiny writing on them says 22K.....maybe a resistor. the search continues.
Ahh, I think it is for use with Borbly buffer maybe?
Russellc
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left upper corner in both (M25 and Sissy) schematics covered main notes regarding Borbely WCF buffer iteration and yes , small u22 caps are for that
as clearly written on few first lines of post #1 in this very thread:
few linked threads are not just extremely fun , they're also informative
as clearly written on few first lines of post #1 in this very thread:
few linked threads are not just extremely fun , they're also informative
really , difference between M25 and SissySIT is sort of minimal ........ "just" upper output part , values of resistors from rails to output gates , few resistor positions around optocoupler and few diodes
so , everything left from optocoupler is practically identical between two amps
10uF is perfect , and 20uF in same place is ..... same perfect 🙂
10uF and 20uF had same price , so I just bought drekload of 20uF , instead of half drekload of 10uF plus half drekload of 20uF
10uF and 20uF had same price , so I just bought drekload of 20uF , instead of half drekload of 10uF plus half drekload of 20uF
Curious if anyone has run 12ohm full range with sissy. I was testing out my Moth Cicadas last night and it seemed sissy was oscillating?
I didn't get sound, only odd scratching noise and a "pft pft" before I shut it down. I pulled speaker cables and fired it up and measure dc offset, normal, plugged in different speakers and normal sound. Plugged the Moths into a different amp, normal music. Tried sissy again and same odd behavior?
Haven't explored anything further, just surprised by this and had assumed that sissy would be a perfect fit for single driver full rangers.
Tubesguy passed along his Token's so I will swap out mine and get rid of the bandaid vreg, not sure this explains it, might be another of those mysteries that remain unsolved
.. dB
I didn't get sound, only odd scratching noise and a "pft pft" before I shut it down. I pulled speaker cables and fired it up and measure dc offset, normal, plugged in different speakers and normal sound. Plugged the Moths into a different amp, normal music. Tried sissy again and same odd behavior?
Haven't explored anything further, just surprised by this and had assumed that sissy would be a perfect fit for single driver full rangers.
Tubesguy passed along his Token's so I will swap out mine and get rid of the bandaid vreg, not sure this explains it, might be another of those mysteries that remain unsolved
.. dB
my main speakers are RCA LC1B , 16R nominally ....... practically extended range 15" (no xover there) with tweet on top (having 4uF in series)
no odd behavior, anywhere
and I can bet that 70% of test speakers in our caves are nothing else than dirt cheap boombox FR
so , problem must be somewhere else , not in Sissy's sissyness........ more likely in sum of your band-aids
no odd behavior, anywhere
and I can bet that 70% of test speakers in our caves are nothing else than dirt cheap boombox FR
so , problem must be somewhere else , not in Sissy's sissyness........ more likely in sum of your band-aids
This confirms what I thought. Will have to explore once I have it operating optimally again.
Will put it on the scope under load to see behaviour.
In the meantime will just have to deal with Maggies and other franken creations
.. dB
Will put it on the scope under load to see behaviour.
In the meantime will just have to deal with Maggies and other franken creations
.. dB
it's possible that with easier load (12R) , your VReg is acting funny , in other (layman) words - not being damped enough
easy (temporary) cure - just put 16R big and dumb resistor in parallel to Cicada driver
easy (temporary) cure - just put 16R big and dumb resistor in parallel to Cicada driver
Cinemag transformers
Delivered today, not bad, little over 4 weeks and here they are. Looking forward to this one!
I will finish up the boards and post clear photos, in case of problems later.
Russellc
Delivered today, not bad, little over 4 weeks and here they are. Looking forward to this one!
I will finish up the boards and post clear photos, in case of problems later.
Russellc
rootin' for ya!
First time that I got magic smoke coming out. Iq went quickly from mV to +1V, I was too slow to turn it off. DC offset was 0.8V so nothing special there. 10min later I dropped my phone and it got broken too.
Quick study shohs that Q3 is probs only part that took damage. Smoke between drain and source pins.
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which means that you didn't set P1 initially to 0 Ohms , or made some other mistake if Iq went up really quickly ...... when everything is OK < it can't go quick anywhere , due to enormous time constant of P2-R18-C11-R19
which means that you didn't set P1 initially to 0 Ohms , or made some other mistake if Iq went up really quickly ...... when everything is OK < it can't go quick anywhere , due to enormous time constant of P2-R18-C11-R19
Second channel seems to work, so I probs have made a mistake somewhere. Gotta double check.
Oh, this is not SIT btw (schematics above)
Measuring over R17 and R19 gives me funny readings, R17 2,6ohm and R19 100ohm while on pcb.
Measuring over R17 and R19 gives me funny readings, R17 2,6ohm and R19 100ohm while on pcb.