Because those were plenty statistically back when designed (asked some of you to check your BL stashes and you gave mean value graphs, remember?), and good for the gain/THD goals. As you can also see, the Yfs rise gets slower with ID rise. ID is not IDSS since we have Rs local feedback resistors designed in. But dissipation and its extra noises stay in check with BL. So Yfs/ID is much closer to higher samples when in circuit than you may initially think, bcs Rs brings it way down from IDSS. We have implemented K170V also in some cases that they were on hand, like Franz's one if you also remember.
I do remenber all the above points but if you had ilimited quantities of jfets and wanted to build a very high gain riaa, what idss range would you choose ?
So can be the reason that I prefer my SE RIAA with 10.5mA Idss over my balanced RIAA with 8.5mA Idss
If I was you I will try, because depending the recording & your system including acoustic treatment can vary. I will start trying to lower 01.gr each step/time, every time/step you reduce weight you can hear more highs & less lows so it's a question of your personal taste & If you don't want to modifie the VTFwith each record you have to chose a compromise that more or less all your records sounds well. I really surprised lowering the tracking force because I had 2.5gr as you, first setp I hear more mids I next step hear more highs, finally I stopped when hear highs clear without losing mids & lows if your cart it has excesively weight you lose focus: bass difused, mids & highs lost.
Last edited:
I will try, but we have different tonearms also etc. etc. It will show in practice. I will check out an AC mains IEC filter also.
I have tried 2.15gr & sounds good but It's possible that this lower VTF can be a signal that 15nF RIAA it's not well adjusted?
I'm interested wich AC main filter you will use, speaking about other way to improve the RIAA lately I have implemented "active shielding" in the RCA cables between the NJFET RIAA & the preamp with good success
Can Merlin confirm:
Cinch = single pole RCA plug = Phono plug ?
hot = signal flow ?
cold = signal return ?
outer black pair = braided shield ?
middle black pair = ????
Cinch = single pole RCA plug = Phono plug ?
hot = signal flow ?
cold = signal return ?
outer black pair = braided shield ?
middle black pair = ????
For your info, IEC filter in my single box LMC 61dB, positive for smoother but even more distinct highs, less ''surface'' noise. 2.5g best at 220R PRP load. Mission 774 arm, VTA (rake angle) very slightly nose down. My Riaa curve textbook flat. Compatible to most of my records, no surprises.
I have 220R Shinkoh load so I must adjust 15nF RIAA, thanks Nick your information has been very useful for me.🙂
What's LMC 61 dB?
Last edited: