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duderduderini 15th December 2008 09:46 AM

Zobel filter for MC head amp?
Hi Guys
I just fitted my Ortofon rondo red and i must say out of the box it comletely sucks.. very harsh.. even my dog left the room!!! Compare this to a Audio Technica AT440ml which is a lot smoother..
SO I was investigating sowter stepups and it talked about a zobel across the secondaries and I was wondering wether thats the case for
head amps. I built a Neville roberts head amp and I have also tried a SUT for the previous ortofon MC20MK11 and I must say the sonic signature of the rondo red and mC20 are similar.
How do I rid myself of this Harshness?
Or should I just put it back on ebay and resell it?
Nick Mega

analog_sa 15th December 2008 10:49 AM

Re: Zobel filter for MC head amp?

Originally posted by duderduderini
Or should I just put it back on ebay and resell it?

Probably best idea. Snubbers across secondaries of transformers are there to reduce ringing. Don't think good transformers benefit from this at all.

I don't know your cart but use several other Ortofons and don't find them harsh at all. Could it be other components in your system exaggerate the harshness? Care to describe your system?

Let it play for at least 20 hours before you take a final decision. Make sure VTA and alignment are ok.

duderduderini 15th December 2008 10:59 AM

HI and thanks
system is head amp from neville roberts
link is
Phono amp is c3g 6sl7 phono riaa amp loading r there is 47K
I have yet to grab a set of transformers cause I had this exact problem with my MC20 Super Mk2 even with a pair of sut(AT ones) that I borrowed. No matter what phono amp i built and believe me I built a LOT of them to try it was the same prob as with the MC20 as it is with the rondo.
The system sounds pretty good with a lowly at 440ml mm cart
Yes I checked vta and alignment and tracking force
So obviously there is less wrong with my setup with a MM than there is with a MC. Can you glean anything from that?

duderduderini 15th December 2008 10:31 PM

I will just sell it
I have decided to resell the cartridge. I am giving up on Moving coils as I have now tried 3 different ortofons with the same annoying harshness. I think thats a function of two things.. the capacitance/inductance/resistance of my amp setup which is all tube and secondly the ear injury I sustained many years ago at the hands of a fool firing a high powered rifle off a few feet from my ear..
The fact that moving coils can have quite high peaks above the 20KHz region is well documented.. I wonder if I am not hearing harmonics, well not hearing them but at least discern them as an unbearable buzz in said left ear.
With the 2 Moving magnets I tried.. no such problems, go figure.
The AT 440ml is paradoxically smooth in my system as was the shure V15MK3.
So i am figuring an AT 150MLX or ortofon Bronze at this point as I want something a little more tonally accurate than the 440ml.
To everyone have a peaceful Christmas and let the love shine through

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