t.bone sct800 polar pattern mod? (low high end´s ??!!)

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commanderberti

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hi, today i have insatalled a dual capsule in my SCT800, c5&r9 are already an PCB also polar pattern voltage are wired.. everything works with a polar pattern PSU.. BUT: sound are with low high end´s... any ideas why?
 
hi, today i have insatalled a dual capsule in my SCT800, c5&r9 are already an PCB also polar pattern voltage are wired.. everything works with a polar pattern PSU.. BUT: sound are with low high end´s... any ideas why?
Hi @commanderberti

I own two SCT800's which I have modified extensively.
Do you mean that your modded SCT800, now lacks High Frequencies?
" BUT: sound are with low high end´s.."

Is this happening on both sides of the new capsule, can you check ?
And where did you get the new Dual capsule from?

M
 
Hi @commanderberti

I own two SCT800's which I have modified extensively.
Do you mean that your modded SCT800, now lacks High Frequencies?
" BUT: sound are with low high end´s.."

Is this happening on both sides of the new capsule, can you check ?
And where did you get the new Dual capsule from?

M
yes! an yes on both sides.. if i moound the capsule in a sct2000, everything sounds fine.. but in schematics.. i dont see no difference round about the capsule circirit.. hmmm
 
yes! an yes on both sides.. if i moound the capsule in a sct2000, everything sounds fine.. but in schematics.. i dont see no difference round about the capsule circirit.. hmmm
If I remember well ... IF... IF
I think I saw a small ceramic capacitor soldered on the "back" of the valve connector.
From Pin 1 (plate) to pin 2 (grid). Which I removed & also changed that crappy original valve.
Check if yours has that Ceramic capacitor 22 pF. (tames HF?)

Or maybe I'm just starting to loose my mind?
Good luck.
M
 

Attachments

  • SCT800- With China Valve.jpg
    SCT800- With China Valve.jpg
    1.9 MB
  • SCT800- With Cap 22 Pf..jpg
    SCT800- With Cap 22 Pf..jpg
    461.5 KB
Last edited:
If I remember well ... IF... IF
I think I saw a small ceramic capacitor soldered on the "back" of the valve connector.
From Pin 1 (plate) to pin 2 (grid). Which I removed & also changed that crappy original valve.
Check if yours has that Ceramic capacitor 22 pF. (tames HF?)

Or maybe I'm just starting to loose my mind?
Good luck.
M
ok this makes it a bit better.. but not so as if the capsule is in the SCT2000. now i think it takes a differenz if i take a multi patteren capsule in a tube circurit, it it is a sct800 (only one tube stage) or a sct2000 circurit (cathode follower, 2 stages tube.. seems to sound better withe 2 plate capsules.. ).. hmmm
 

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