Hi all
I'm glad to found this community with such a great know-how.
I hope you guys can help me with some questions
1) Do we want our OPT to saturate @ low frequency, as a part of soundforming? I’ve heard a lot about „good“ OPT saturation being important for guitar tone.
If yes – is there any knowing numbers, for example
xx kGauss @ yy Hertz @ zz Volt RMS = good tone ???
I wound 2 OPTs (not that much) and both were very oversized, like 12KG @ 40Hz at full voltage swing. Both sound OK, but maybe they could be better with bit more saturation???
Is there any rules like: for modern high gain – stiff OPT with good low end, for vintage tone – more saturation, or others? Or is it like bigger = better?
Any help would be appreciated.
2) Primary inductance
Is important for low end response, but is frequency and level dependent. And the measurement is quite tricky.
Do we have to take care of it at all? Let me explain:
From my understanding, it is almost impossible to have too low Lpr with decent design.
Small example: For high 8k Raa the impedance of Lpr should be at least 16k @ lowest frequency of interest (say 40Hz) and @ > ½ power (from turneraudio).
This is about 65H. (80H for 30Hz)
Taking even small core with 28mm x 32mm and path length = 168mm and calculating the required core-mue for very low Np= 1000 (formula from turneraudio page)
I’m getting mue = 11900, and
Mue = 5290 with Np = 1500.
GOSS (M6) will have about 10000 with 1x1 lace, right? So even smallish 1000turns primary will be good enough for 40Hz response, from inductance-point of view
So flux density (core saturation) limits the low end performance on almost all designs (using M6 steel), not the inductance.
Please, correct me if I’m wrong.
Thanks
dimashek
I'm glad to found this community with such a great know-how.
I hope you guys can help me with some questions
1) Do we want our OPT to saturate @ low frequency, as a part of soundforming? I’ve heard a lot about „good“ OPT saturation being important for guitar tone.
If yes – is there any knowing numbers, for example
xx kGauss @ yy Hertz @ zz Volt RMS = good tone ???
I wound 2 OPTs (not that much) and both were very oversized, like 12KG @ 40Hz at full voltage swing. Both sound OK, but maybe they could be better with bit more saturation???
Is there any rules like: for modern high gain – stiff OPT with good low end, for vintage tone – more saturation, or others? Or is it like bigger = better?
Any help would be appreciated.
2) Primary inductance
Is important for low end response, but is frequency and level dependent. And the measurement is quite tricky.
Do we have to take care of it at all? Let me explain:
From my understanding, it is almost impossible to have too low Lpr with decent design.
Small example: For high 8k Raa the impedance of Lpr should be at least 16k @ lowest frequency of interest (say 40Hz) and @ > ½ power (from turneraudio).
This is about 65H. (80H for 30Hz)
Taking even small core with 28mm x 32mm and path length = 168mm and calculating the required core-mue for very low Np= 1000 (formula from turneraudio page)
I’m getting mue = 11900, and
Mue = 5290 with Np = 1500.
GOSS (M6) will have about 10000 with 1x1 lace, right? So even smallish 1000turns primary will be good enough for 40Hz response, from inductance-point of view
So flux density (core saturation) limits the low end performance on almost all designs (using M6 steel), not the inductance.
Please, correct me if I’m wrong.
Thanks
dimashek