NFB in 2203, which OT tap to use?

[BesaMoogie]

Hi,
does anyone know, which is the usual OT tap used in 2203 circuits with a 100k resistor, 4 ohm or 8 ohm?
And were there any changes in the 2203 line, let’s say late 70ies Jmp vs early 80ies Jcm800?
Thanks

 

[Chubbs]

Believe they started with 4ohms on the jmp’s and moved to 8 ohms on the later 800’s. If I remember correctly when they shipped amps with 6550’s 4ohm was standard, then when EL34’s were used again they switched back to 8ohm.

 

[Racerxrated]

8 ohm afaik with an 800. If you want a tighter response, move it to the 16. The other way, go 4ohm.

 

[Racerxrated]

Hi,
does anyone know, which is the usual OT tap used in 2203 circuits with a 100k resistor, 4 ohm or 8 ohm?
And were there any changes in the 2203 line, let’s say late 70ies Jmp vs early 80ies Jcm800?
Thanks

The power transformers in the late 70 can sometimes be lower voltage; PV around 380 or so but this isn't a rule as a 79 I had was up near 500v. The early 80s 800s had the higher voltage PTs pretty consistently ime. The early 800s had those red 'lego caps' as well vs the later 70s not using them very often. JMPs will sound a tad less bright/aggressive vs the early 800s but that's not to say they aren't aggressive.

 

[BesaMoogie]

Thanks, will go with 8 ohm in my DIY clone. I`ve got contradictory information weather it`s the 4 or the 8 ohm tap