Thank you.
I am testing with a low efficiency speaker so I can't tell for sure about noise. I did put the AC lines in braided shielding so hopefully it will be OK.
I will know when I finish the left channel and listen to it with my efficient speakers.
In deciding between Sissy sit or M25 "which to build first" (will build both) was wondering how hot does Sissysit get? I could go M25 first and transplant into current Deluxe4 chassis where M2 now lives....Im thinking dual mono for Sissy, and that wont happen for Deluxe 4, I dont like crowded Amps. I could transplant Sissy into my DIY F5 case, already dual mono but that is where I was thinking F7 clone would go. It is slightly larger than Deluxe 5, size and heatsink wise.
Russellc
Russellc
rails sum , multiply with Iq
which is , for both amps , anything you set between 1A7 and 2A
so , max case - 22V5 x 2 x 2A = 90W of heat
completely ok with 4U/400
4U/300 ....... gimme a break ..... that's super sissy
Well, the deluxe 4 is 300...so call me sissy! No room for dual mono to be sure, I have Aleph J in one and heat under control...would be nice for extra room for dual mono! Never understood why not 400 to match Deluxe 5...
Russellc
I finished my SissySit on the weekend and it is up and running and making music.
I had completed and tested the right channel prior to the weekend (see post #395). Chassis information is in post #379.
The left channel was completed and fired up and biased with no problems at all. Upon first turn on, the offset was about 0.5V and the voltage across 0R1 was a bit high at about 20mV. I think the right channel had started at about 1V offset and less than 10mV across 0R1, but I am not 100 percent sure as I didn't write it down and my memory is not the best.
The amplifier is completely quiet with 102 dB speakers. I paid attention to proper grounding, twisted together wires with their ground returns, and also put the line AC wires in steel braid sheathing. I did not shield the Cinemag transformers.
The amplifier does not run too hot. I can keep my hand on the heat sinks indefinitely. I had drilled the Mosfet and SIT attachment screw holes through the heatsink base between the fins so I measured the temperature of the screws from the outside of the heatsinks and it was 46 degrees C with ambient at 20 degrees C. Iq was at 1.8A. So that was the heatsinks' hottest temperature, with the fins cooler. The heatsinks are 150mm x 400mm by 50mm, with the base 10mm thick and the fins 40mm long.
My previous amplifier setup was biamping with DiyAudio Sony VFET amp on bass and Sony 2SJ28 Hammond choke loaded L'Amps on the mids/tweeters. My preamp is a Sony VFET Luminaria, so there was a lot of VFET goodness happening already. Because of that, the SissySit full range in place of the DiyAudio Sony VFET and L'Amps was not a dramatic change, but still a noticeable change for the better. The high frequency became more extended where previously it seemed a bit rolled off. Instruments and voices became more distinct and seemed to occupy more of their own space. It was as if the definition and contrast was turned up a bit.
So I am quite happy with my new SissySit. Thank you, Zen Mod.
I had completed and tested the right channel prior to the weekend (see post #395). Chassis information is in post #379.
The left channel was completed and fired up and biased with no problems at all. Upon first turn on, the offset was about 0.5V and the voltage across 0R1 was a bit high at about 20mV. I think the right channel had started at about 1V offset and less than 10mV across 0R1, but I am not 100 percent sure as I didn't write it down and my memory is not the best.
The amplifier is completely quiet with 102 dB speakers. I paid attention to proper grounding, twisted together wires with their ground returns, and also put the line AC wires in steel braid sheathing. I did not shield the Cinemag transformers.
The amplifier does not run too hot. I can keep my hand on the heat sinks indefinitely. I had drilled the Mosfet and SIT attachment screw holes through the heatsink base between the fins so I measured the temperature of the screws from the outside of the heatsinks and it was 46 degrees C with ambient at 20 degrees C. Iq was at 1.8A. So that was the heatsinks' hottest temperature, with the fins cooler. The heatsinks are 150mm x 400mm by 50mm, with the base 10mm thick and the fins 40mm long.
My previous amplifier setup was biamping with DiyAudio Sony VFET amp on bass and Sony 2SJ28 Hammond choke loaded L'Amps on the mids/tweeters. My preamp is a Sony VFET Luminaria, so there was a lot of VFET goodness happening already. Because of that, the SissySit full range in place of the DiyAudio Sony VFET and L'Amps was not a dramatic change, but still a noticeable change for the better. The high frequency became more extended where previously it seemed a bit rolled off. Instruments and voices became more distinct and seemed to occupy more of their own space. It was as if the definition and contrast was turned up a bit.
So I am quite happy with my new SissySit. Thank you, Zen Mod.
Attachments
Congratulations on what sounds to be a fruitful build.
Keeps hearing about Cinemags. Some questions, if you don't mind.
1. Does the amplifier as it is provide more than adequate gain from the nominal
2.1V SE input?
My speakers are 94db @ 8 ohms, and I'm using a tube buffer pre amp.
2. They are reputed to be very detailed. Do you have basis to compare them
sonically to Edson, and/or Jensen?
3. What is the complete model number for your Cinemgas?
I realize that some time should be passed before evaluating too closely, and look forward to further comments on your new amp.
Keeps hearing about Cinemags. Some questions, if you don't mind.
1. Does the amplifier as it is provide more than adequate gain from the nominal
2.1V SE input?
My speakers are 94db @ 8 ohms, and I'm using a tube buffer pre amp.
2. They are reputed to be very detailed. Do you have basis to compare them
sonically to Edson, and/or Jensen?
3. What is the complete model number for your Cinemgas?
I realize that some time should be passed before evaluating too closely, and look forward to further comments on your new amp.
Congratulations Ben! Glad it has all come together perfectly.
My struggles continue.
I have replaced the 2.5v VR1 as well as the optos, able to bias both channels to 2.5A ( best option for both channels to be the same) both outputs zero easily.
Right channel buffer set without trouble but left was being a little troublesome. Rail voltage of 23 plus minus into the BD devices. Getting + 10 out of the BD139 but 0.5 volt on the negative side which should be - 10. Checked all solder point and continuity. Seems the bjt is not functioning. Getting very close to starting over with a fresh set of boards but will have one last go at troubleshooting this last hurdle.
Luckily I have a beautiful M2x playing music to keep me in a happy place while I do all this.
.. dB
My struggles continue.
I have replaced the 2.5v VR1 as well as the optos, able to bias both channels to 2.5A ( best option for both channels to be the same) both outputs zero easily.
Right channel buffer set without trouble but left was being a little troublesome. Rail voltage of 23 plus minus into the BD devices. Getting + 10 out of the BD139 but 0.5 volt on the negative side which should be - 10. Checked all solder point and continuity. Seems the bjt is not functioning. Getting very close to starting over with a fresh set of boards but will have one last go at troubleshooting this last hurdle.
Luckily I have a beautiful M2x playing music to keep me in a happy place while I do all this.
.. dB
Mazeppa,
I have the Cinemag CMOQ-4HPc, which is the high nickel version. There are some impressions of the various transformers here:
Babelfish M25 , AKA M2 on steroids , AKA M2-XA25 bstrd - kit packages Post #23.
Zen Mod can probably tell you whether you need additional preamp gain or not.
I have the Cinemag CMOQ-4HPc, which is the high nickel version. There are some impressions of the various transformers here:
Babelfish M25 , AKA M2 on steroids , AKA M2-XA25 bstrd - kit packages Post #23.
Zen Mod can probably tell you whether you need additional preamp gain or not.
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It pays not to give up 
playing music ( albeit on crappy Bose speakers donated to the sacrificial cause )
fixed the buffer by replacing the BD140 device - no idea why or how it went bad but replacing it allowed me to bias the buffer on that channel and it zeroed easily.
the amp is biased at 2.5 A but offset zero's and after 45 min of playing the heatsinks are only 40 deg C
I will cook it for a few days before moving it up to my system to hear what it can really do.
thanks ZM
..dB
playing music ( albeit on crappy Bose speakers donated to the sacrificial cause )
fixed the buffer by replacing the BD140 device - no idea why or how it went bad but replacing it allowed me to bias the buffer on that channel and it zeroed easily.
the amp is biased at 2.5 A but offset zero's and after 45 min of playing the heatsinks are only 40 deg C
I will cook it for a few days before moving it up to my system to hear what it can really do.
thanks ZM
..dB
Thanks all - appreciate all the support ( moral support from the community is the most important ! )
The devices are cooking at around 65deg C but the heatsink measures 40 with my temperature gun .
If we use Papa's assessment this would be "bloody hot" at around 55 degC
I picked them up off e-bay , I think they originate as heatsinks off wind turbines. I had to grind down a lip and removed part of the lower fin to make it work for the build but they are solid and effective.
@Flocchini has created a masterpiece using the same heatsinks.
..dB
The devices are cooking at around 65deg C but the heatsink measures 40 with my temperature gun .
If we use Papa's assessment this would be "bloody hot" at around 55 degC
I picked them up off e-bay , I think they originate as heatsinks off wind turbines. I had to grind down a lip and removed part of the lower fin to make it work for the build but they are solid and effective.
@Flocchini has created a masterpiece using the same heatsinks.
..dB