Excessive capacitance with a MM cartridge will cause a peak in the audible range before any roll off at the top of the range, and this will be perceived as added brightness.
Ortofon carts are too hot for my phono preamp?
When I need hardware advice, I always come to Audiogon for the true experts. Thanks in advance and happy Easter!
So after much trial and error, I THINK I have deduced that my Ortofon 2M Bronze and 2M Black cartridges are too hot for my Avid Pulsus phono preamp. Some softer recordings are fine, but I think I am hearing some distortion with loud transients and even sometimes on relatively loud vocals.
I have a Pro-ject tube phono preamp I swap in and I don’ t hear that distortion. I never hear that distortion with other sources.
Given my investment in 3 Ortofon 2M carts (1 Bronze, 1 Black, 1 Black SE) and the Pulsus, is there anything I can do to step down that signal from the carts without doing any damage to the sound?
Any other thoughts?
(BTW the 2 turntables I am using are a Rega P3/24 and an older Rotel. Meridian preamp has variable gain settings on inputs and I can hear the distortion at any setting.)
- ...
- 22 posts total
Sell both your phono preamps. The Avid, at 48dB gain is apparently too sensitive to overloading by your not abnormally high output MM cartridges, and the Pro-Ject because you don’t respect its quality. Then buy a Spartan 20, which is £500 and has impeccable accuracy, generous overload margins, and negligible noise. You will be hearing your records, not your preamp. |
This review at HFN says the Avid has an overload margin at MM inputs of 46mV. It’s not obvious to me that the phono stage per se is responsible for the “problem”, if it even is a problem.46mV is 10X the cartridge output at a stylus velocity of 5cm/sec at 1kHz. Decent headroom at least. Further, HFN auditioned it with a Shure V15, which I believe also has nominally a 5mV output. Viridian made a good point about capacitance. Check phono cable capacitance. Then check the recommended capacitance for the cartridge and the input capacitance of the stage. Input capacitance adds to cable capacitance. |
@jji666 I can vouch for the cable from turntable to phono stage make a big difference. My Music Hall mm5-3 came with its own, directional, RCA cables. They’re the best I own, and, I think, play a major role in the sound quality of the vinyl on my system. My phono stage is rather modest, but I’m not getting any distortion of which I’m aware. Good luck sorting your situation. |
It's not obvious to me either, other than by process of elimination it is the combo of those carts with that phono pre that yields distortion. I have a few integrated amps with phono stages in them...I will see if I can reproduce the distortion through anything else. The above article also says that the headroom isn't as indicated in the specs. And those carts have been measured at hotter than 5mV albeit as above there is some question about that. What I do know is that specific combination produces distortion. The Avid is really good at digging out details from some records, and with the shibata on the 2M Black and Black SE I get some great detail, again from some recordings. Those that are at higher volume are the issue. |
- 22 posts total