Yes, I like to throw the extra Jfet in to save everybody, especially me, some trouble.
Yes! Big thanks to Ban Mah and Mr. Pass!
Q4 was blown and the extra JFET included saved me some time.
The FE kit is singing again on the Mofo!
Now, do I borrow it back to my friend?!? Haha.
Q4 was blown and the extra JFET included saved me some time.
The FE kit is singing again on the Mofo!
Now, do I borrow it back to my friend?!? Haha.
I have tried about eight gain devices, both tubed and solid state, sometimes chained in sequence to get the gain, including built in preamp of TA 4650 (like a nice classic pentode preamp) and the Pass Korg B1, with the Sony SK60 build over the last six months. FE 2022 has been the best so far with it overall. It walks the fine line of transparency without sterility. The SK60 Pass build is a liquid and analog sounding device single ended (or mu follower whatever), so good booster stage.
I have to admit a prejudice against anything BJT (as opposed to FET etc.), but I guess with the flock of JFET current source thingies, it worked out.
I have to admit a prejudice against anything BJT (as opposed to FET etc.), but I guess with the flock of JFET current source thingies, it worked out.
I lashed it to the same 36V linear regulated power supply I use for the SK60 build. However, using the Sony TA 4650 chassis, I used separate RCA inputs and outputs for it to keep the power amp portion open for experimentation through its own RCA jacks. The 4650 chassis with all the inputs and outputs on it allowed for some versatility.
So I started with the blown 4650 and some harvested, still working VFETs, and wound up with this working charm amp. Given all my electronic foolishness and two thumbed assemblies along the way, I am surprised it resulted in one of the best amps I have heard and a very nice tribute descendant of the 4650.
So I started with the blown 4650 and some harvested, still working VFETs, and wound up with this working charm amp. Given all my electronic foolishness and two thumbed assemblies along the way, I am surprised it resulted in one of the best amps I have heard and a very nice tribute descendant of the 4650.
At various times, direct to no crossover panels @ 3.6 ohm, about 89 db efficient full range (yes, it works) but mostly dedicated with active crossover to good efficiency 75 inch ribbons from 300Hz to 7Khz @ 6 ohms in a four way active crossover setup.
I have also used it with various mini speakers. When I first built SK60, I was using some dismal 4 inch vintage Radio Shack full rangers and with the speakers sitting on the floor, the amp threw a charming image a third of the way up the wall of my listening room. Couldn't believe the sound was coming from these ancient wheezers.
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I sent a couple hundred recently, so I suppose they'll be listed shortly.
You always make such beautiful chassis’, if I remember correctly. So looking forward to future ones 🙂
