They’re both laterals. 
Just different packaging. Exicons are equivalent to Hitachi J49/K134. The Hitachi J160/K1056 (or J162/K1058) are TO3P versions of the TO3 Hitachi laterals.
The TO3Ps will be easier to replace with new Exicon laterals if needed. Exicon’s TO3 laterals are at end of life.
Just different packaging. Exicons are equivalent to Hitachi J49/K134. The Hitachi J160/K1056 (or J162/K1058) are TO3P versions of the TO3 Hitachi laterals.The TO3Ps will be easier to replace with new Exicon laterals if needed. Exicon’s TO3 laterals are at end of life.
*Mostly. There are slight differences in the FET data sheets, and likely differences in the amp schematics, but that’s beyond my expertise to explain. 
I remember the 860 has that cool shoebox form factor. However your A400 looks a lot cleaner.
If I recall correctly, don’t the 860s have an odd power supply arrangement (some research may be needed)? That could skew more points for the A400.
I remember the 860 has that cool shoebox form factor. However your A400 looks a lot cleaner.
If I recall correctly, don’t the 860s have an odd power supply arrangement (some research may be needed)? That could skew more points for the A400.
Last edited:
What sets these Soundcraftsmen apart from other amplifiers is the Phase Control Regulation (PCR).
That's the pcb on top of the supply caps.
What it does is it controls the thyristors firing angle in accordance to the power demanded by the amplifier.
My PCR800 works on regulated rail voltages of +/- 70Vdc.
The unregulated voltage is higher at +/- 95Vdc,, so effectively there's a +/- 25V headroom.
Even under full power, there's no sag in the rail voltages because it doesn't come out of regulation.
That's the pcb on top of the supply caps.
What it does is it controls the thyristors firing angle in accordance to the power demanded by the amplifier.
My PCR800 works on regulated rail voltages of +/- 70Vdc.
The unregulated voltage is higher at +/- 95Vdc,, so effectively there's a +/- 25V headroom.
Even under full power, there's no sag in the rail voltages because it doesn't come out of regulation.
Sound wise, I have no issues with the Soundcraftsmen. They can still be used for the home. Personally, they sound better than some of their competitors of that time.
The amplifier circuit itself is quite ordinary though. The strength of the PCR amps is in the voltage regulation. The way it was done was very innovative but it never caught on. Maybe due to it's complexity.
I actually have 3 Soundcraftsmen. One is a PCR800 while the other is the 860. The 3rd unit is a MTX Soundcraftsmen A200. I believe this last one shares the same circuit but without the phase control. I don't really use them. They are part of my collection of vintage amps. Reminds me of a bygone time in the 80s when I was first introduced to the PCR800.
The amplifier circuit itself is quite ordinary though. The strength of the PCR amps is in the voltage regulation. The way it was done was very innovative but it never caught on. Maybe due to it's complexity.
I actually have 3 Soundcraftsmen. One is a PCR800 while the other is the 860. The 3rd unit is a MTX Soundcraftsmen A200. I believe this last one shares the same circuit but without the phase control. I don't really use them. They are part of my collection of vintage amps. Reminds me of a bygone time in the 80s when I was first introduced to the PCR800.
Do you think the PCR 860 is better than Hafler and B&K amps ?
How do you feel about using a film cap in the audio path ? C-1 is the only one in the audio path, 22uf 35V
How do you feel about using a film cap in the audio path ? C-1 is the only one in the audio path, 22uf 35V
All of them are competently designed. Circuit wise, the 860 is the most basic, followed by the B&K (ST140) and finally the Hafler (DH220).
What is common amongst them is their use of 2SK135/2SJ50 lateral mosfets.
Though the 860 has the simplest circuit, it doesn't mean the sound is the worse. Even decades later, these vintage amps have wide appeal.
Regarding the input capacitor C1, I believe it is a non-polar e-cap. It is advisable to replace that with a film cap. A 1uF or 2uF is sufficient.
What is common amongst them is their use of 2SK135/2SJ50 lateral mosfets.
Though the 860 has the simplest circuit, it doesn't mean the sound is the worse. Even decades later, these vintage amps have wide appeal.
Regarding the input capacitor C1, I believe it is a non-polar e-cap. It is advisable to replace that with a film cap. A 1uF or 2uF is sufficient.