So my Sissysit is finally playing music! Sound really good, sweet and spooky realism. Everything went smoothly apart from a caput input bias trimpot that was stuck at max.. first time that I see that. Must have done 50 turns before realizing it was not working ahah
I think I will go for the opto mod just so that its a little bit more stable at each power up..
Zenmod, any particular brand of 6n139 will do? What did you use for your test?
Thank you for this nice amp!
Hubert
I think I will go for the opto mod just so that its a little bit more stable at each power up..
Zenmod, any particular brand of 6n139 will do? What did you use for your test?
Thank you for this nice amp!
Hubert
no particular brand for 6N139
those are damn industrial parts , I reckon all of them made properly
Great thank you !
Hey ZM! I’m thinking of ditching my sissy shared PSU and going for dual mono, kinda like what I’ve seen in your build pics. Trying to decide if I find a PSU, build my own zm-style board, or just go with big cans and point to point wiring. Would like to get at least 40kUF per rail (160kUF total) and CRC. Any suggestions?
Perfect - thanks! Good to have each PS isolated with CL60? Or would one and a shared ground be ok?
Typical AC "power conditioners" don't do much except put a couple leaky MOVs across the lines in an attempt to lull the user into a false sense of security. Any filtering that may be present is usually up in the RF range, and certainly won't compensate for heavy motor or compact florescent loads on your local grid.
I have also watched the DC offset on the output of some of my amps fluctuate when my refrigerator or furnace blower kicks on. I also suspected that using a florescent light near my stereo system caused a noticeable degradation in the quality of sound. The one amp that doesn't exhibit these perturbations is my F6, which has regulated power supplies for each channel. Adding power regulation is a more complex process than one might suspect, even given the availability of some boards to facilitate such a build.
Unless you notice a definite problem with the sound of your amp, it's probably best to follow Zen Mod's advice and don't worry too much.
Edited to add:
My critical source components (CD player, preamp, network streamer/DAC) have regulated power supplies that are housed in separate chassis as large as the main components themselves. These have enough current capacity to supply small power amplifiers, and make a very noticeable difference in the quality of my system.
I have also watched the DC offset on the output of some of my amps fluctuate when my refrigerator or furnace blower kicks on. I also suspected that using a florescent light near my stereo system caused a noticeable degradation in the quality of sound. The one amp that doesn't exhibit these perturbations is my F6, which has regulated power supplies for each channel. Adding power regulation is a more complex process than one might suspect, even given the availability of some boards to facilitate such a build.
Unless you notice a definite problem with the sound of your amp, it's probably best to follow Zen Mod's advice and don't worry too much.
Edited to add:
My critical source components (CD player, preamp, network streamer/DAC) have regulated power supplies that are housed in separate chassis as large as the main components themselves. These have enough current capacity to supply small power amplifiers, and make a very noticeable difference in the quality of my system.
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Some feedback after listening to the sissysit for a couple of days. It’s really a great amp, I have the m2 to compare and all I can say is wow. Deep and wide with a lot of definition and 3D. Great for all style of music, listening to Tool Aenima at this moment and it sounds just right. M2 seems a little bit more in your face and dry. M2 are mono blocs with better psu and sissy is in shared psu stereo amp. Now that I have listen to it, I think Sissysits are going into the mono blocs to replace the m2s 
As for the offset, it’s start cold at -120mv that settle around +/-20mv once at temp equilibrium. Would I see a difference with the new opto configuration? I think its not that bad.
Don’t know why but building this amp seem to have pushed me to buy another pair of 2sk182 and some ixfn140n20p...
As for the offset, it’s start cold at -120mv that settle around +/-20mv once at temp equilibrium. Would I see a difference with the new opto configuration? I think its not that bad.
Don’t know why but building this amp seem to have pushed me to buy another pair of 2sk182 and some ixfn140n20p...
Everything was going great and coming together nicely. The SITs biased nicely with just a little drift. The biasing of the buffer dialed in and I was able to zero the offset buffer on the first channel. Now for the last adjustment and music, but when I turned the R7 nothing happened. I tried both directions, but the offset remained constant. I Even tried reflowing the connections on the resistor.
Does anyone have any suggestions before I replace R7?
Does anyone have any suggestions before I replace R7?
damn
I'm measuring all trimpots (side to side and side to mid) , more to be sure that wrong value wasn't in bag , but I'm not testing are they actually changing value when fiddling
O Tempora O Mores!!
from now on , boring task of obtaining strictly Bourns , even if I had few dudes even from them, original without doubt
I'm measuring all trimpots (side to side and side to mid) , more to be sure that wrong value wasn't in bag , but I'm not testing are they actually changing value when fiddling
O Tempora O Mores!!
from now on , boring task of obtaining strictly Bourns , even if I had few dudes even from them, original without doubt