Naw it's fine. That was just one of my lame attempts at humor.. The good thing is ZM offers the "no questions asked, lifetime warranty and guarantee of stellar trouble free operation and pinnacle of happiness" on all of his creations...
'nother note, people get way too hung up on the DC offset values. Even 100mV would be absolutely fine and makes no difference to anything. .1V on a woofer coil is nothing.
Yup, that's true, I would keep working on First Watt amps if I couldn't get below 100. I only have two speaker sets that I would really be bummed out if they got burned, others are reasonable priced. Latest build were inexpensive woofs, less than 30 bucks, but there are 8 in each speaker.
I am FAR from being knowledgeable here, still beginner compared to many. I have no design skills at all. I can follow directions, identify parts, and solder well. It all started after assembling a few Audio by Van Alstein dyna mod kits. I wanted an amplifier, tube, 60 or 70 watts and didn't want to spend 5 grand, I didn't have even if I did. The most I could do was buy a B&K ST 140, and adda few mods suggested to me by Stan Warren. I think that amp was 500 at the time, and that hurt.
Say William, you built a V-fet, right? Years ago I bought in for a set of outputs and boards, but never went forward. How do you describe yours? I need to do something with these, or let someone else go for it. They have sat in a box for years 😔.
I am FAR from being knowledgeable here, still beginner compared to many. I have no design skills at all. I can follow directions, identify parts, and solder well. It all started after assembling a few Audio by Van Alstein dyna mod kits. I wanted an amplifier, tube, 60 or 70 watts and didn't want to spend 5 grand, I didn't have even if I did. The most I could do was buy a B&K ST 140, and adda few mods suggested to me by Stan Warren. I think that amp was 500 at the time, and that hurt.
Say William, you built a V-fet, right? Years ago I bought in for a set of outputs and boards, but never went forward. How do you describe yours? I need to do something with these, or let someone else go for it. They have sat in a box for years 😔.
Ya I built ZM's SissySIT R.3 back in July of '21. I think it's a great amp and it has served me well. I have played around with different ways to provide the voltage gain, just for the hell of it. Kind of like the "will it drive an F4" game, where the voltage gain stage basically determines most of the personality there. But the DEF OS, square law, the VFET, etc.. definitely has it's own flavor and character, compared to a straight follower. It's all Lego blocks to be arranged in different ways to see what you can create and have some nerdy fun doing it..
After listening for a few days now, I am getting familiar with this amp. One thing I can say without reservation is that this is the most transparent amplifier I have owned, or recall listening to. The speakers they are driving are working great. They, being open baffle with a twist they both throw a huge soundstage and are the most transparent speakers I've owned. The combination of this amp and it's inherent transparency with them is extremely satisfying.
The next speaker to try the XA 252 with will be the JBL 4430 clones (Econowaves) and the Altecs. Great job, as usual, Zenmod. Next amps coming up will be in smaller chassis, so maybe I can get another 5U for the Sissysit and not use it for something else like I did when XA 252 came available!
Russellc
The next speaker to try the XA 252 with will be the JBL 4430 clones (Econowaves) and the Altecs. Great job, as usual, Zenmod. Next amps coming up will be in smaller chassis, so maybe I can get another 5U for the Sissysit and not use it for something else like I did when XA 252 came available!
Russellc
How about your "original" M25 amp with mosfets, no SET or SIT. How hot does it get? Big box still needed?
Did an interesting experiment this morning. After several days of listening to XA252, I pulled it out and reinstalled the BA3. I thought perhaps it would be something I couldn't unhear, but no, not at all. Different, but the BA3 still proves itself no slouch! Different, some comparisons are similar to another member here comparing their modded Threshold to their XA 252. Sweet, warm and. Little more rounded.
XA 252 is way more transparent. Super transparent. So transparent, you almost start to cringe, expecting something harsh to accompany this crazy transparency...but no, it stays glorious.
BA3 stays warm and sweet. I would switch back but a cat is now sleeping on it.
Russellc
XA 252 is way more transparent. Super transparent. So transparent, you almost start to cringe, expecting something harsh to accompany this crazy transparency...but no, it stays glorious.
BA3 stays warm and sweet. I would switch back but a cat is now sleeping on it.
Russellc
practically all my amps are happy in 4U/400, being based on common FW PSU - 18Vac secondaries yadayada
exceptions:
- several SE amps made with Tokin SIT - Singing Bush and later ones, all having mucho volts and mucho amps
- Babelfish XA252 and derivatives, based on 28Vac secondaries and decent Iq
That's my next project when I finally get around to it.
Take the Sissy SIT 4.2 with a 50w, 16ohm resistor ( thanks for the heads up @Zen Mod ) into the F4... then I'll compare it with the Macho 252 SIT.
Hopefully the Sissy/F4 will sound as good as the Macho?
Once the Macho stopped the self immolation, I never switched back to the Sissy.
