What's happen when the arm cable capacitance is higher than the recommended load capacitance?
Linn K9 capacitance loading 200pF including arm cable
Linn Ekos capacitance arm cable 220pF
Linn K9 capacitance loading 200pF including arm cable
Linn Ekos capacitance arm cable 220pF
Input valve on the Itch has unusually low Cgp. In this gain stage it adds better Miller than others but you should expect another added 60pF roughly. Remember your post #2020
I listened with 68K as load resistance, treble is better than lowering VTF but still not happy, can be time to play with RIAA treble cap?
If its necessary, why not. That's why its DIY. You can fix for a certain cartridge and restore for another. HiMC like DL-110 with 10K-47K Load would be nice for new "cheap" workhorse cartridge, no cables capacitance considerations.
Does your power amplification use global feedback? I had a time when I raised and lowered the treble and I never got satisfied. Global feedback thru capacitors compensates harmonics with a time delay. My ears hate that so I never use GF in high regions anymore.
Since he has got more than enough cable+Miller capacitance for an AT cartridge (K9 is kind of AT95 with better diamond) it could be just peakiness. Another 68k in parallel or a straight 33k for input load before tweaking the treble cap maybe.
Who knows but I see a pattern in this. Peakyness is not a problem you write home about. Very easy to get rid off. Unasked harmonics is a more common problem seldom talked about. I just measured a HQ coupling cap and it stayed in phase up to some 5-10k then it drifted off around 5-10% above that. Some people are allergic to certain video formats. I am allergic to phase drifts in global feedback
Felipe , I try and try....at the end I add a 18k resistor with the usually 47 kohms. about total 12kohms load.
But the situation is diferent: is for a MC + jensen SUT. This low value can do control the overshot/ringing of the trafo.( verify with gen and oscillo) The treble is good and the rest fine.The reflected load is ( 1:10) 120 ohm.Minimal ten times the resistence of the cartridge ( cart 10 ohm > refl 100 ohm)
The cable capacitance is minimal and the 6n2p-ev is also very low. Sound very well.
I like it.
Cheers
But the situation is diferent: is for a MC + jensen SUT. This low value can do control the overshot/ringing of the trafo.( verify with gen and oscillo) The treble is good and the rest fine.The reflected load is ( 1:10) 120 ohm.Minimal ten times the resistence of the cartridge ( cart 10 ohm > refl 100 ohm)
The cable capacitance is minimal and the 6n2p-ev is also very low. Sound very well.
I like it.
Cheers
Jensen can take an RC or just damp secondary in lower than 47K. Must check that the frequency response remains wide enough when damped heavy. Generator & oscilloscope are best advisers indeed.
I agree, Salas.
The frecuency range is very flat.
I use really a zobel network ( RC - a resistor with a little styro cap in serie), but the important is the resistance value.It works at the ringing region only: the trebles.
Regards
Thanks hego I'm trying now different kind of 47k resistors, 1st was a plastic trimmer to know what's the value I like more, 2nd was a metal film PRP & actually is a carbon wire wound ARMSTRAN.
I have in mind to buy the same AT, could you describe the kind of sound?
Felipe, I use ever no expensive, vulgar an noisy carbon film resistors, like Piher, Bradley Allen, Kimawe or similars.I think . they haven the best sound. (At my taste, of course)
The AT33PTG/II sounds very well, may be a few analytic and detailed, but is also dynamic and natural.I fell in love with this cart and is affordable.
Xto
Regards
The AT33PTG/II sounds very well, may be a few analytic and detailed, but is also dynamic and natural.I fell in love with this cart and is affordable.
Xto
Regards
I changed the 6SN7 for 1578, to be sure I measured again B+ was ok but heaters not, one measured 6.5v and the other 6.2
Now the treble sounds ok, the Itch never sounded so good.
Now the treble sounds ok, the Itch never sounded so good.