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Audio Research PH5 Phono Preamplifier Input Clipping Problem

I have an ARC PH5 phono preamplifier and most of the time it sounds fine.  But on a few of my favorite LP's with wide dynamic range, it will clip and distort on loud sections, especially those with lots of bass content.  This only happens with use of a step-up transformer, without the SUT in line, there is no clipping. I do prefer to use the SUT, as without it I have to turn the volume setting on my ARC REF 3 preamp to a very high level.   I have to conclude that the PH5 is distorting because of high input signal levels, due to the gain of the SUT.   I have tried two SUT's, one with 13:1 and the other at 7:1, both exhibit the same problem (although the lower gain SUT is much better).  The cartridge is Ortofon A90 with .27 mv output.  Given this, would you expect clipping or do you think there is something wrong with the PH5?  I have talked to ARC about this issue, and they seem to think that there is a chance the PH5's maximum input of 70 mv is being reached on these loud sections.  Would appreciate opinions from those that have experience with a similar setup.  Thanks.
Ag insider logo xs@2xscottwsmith
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rauliruegas
13,051 posts
 
Dear @oregonpapa : Did you listen in your system the Ortofon A-90 and then compared against the ART-9?

I did it vs ART 7 and 9 ( both from an audio friend. ) and even that the AT are very good performers IMHO the A-90 is better.

Now, if you did not listening yet the A-90 then make no sense to me your advise.

Anyway, the ball is in the OP field.

regards and enjoy the music,
R.
czarivey
5,946 posts
 
raul,
no matter how sooper-dooper-good Ortofon A-90 sings, the PH5 ain't enough. 
oregonpapa offers the most reasonable solution to preserve the best sound of whole system. 
forget about your little piece, it's too small no matter how good it is compared to the whole system synergy.

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rauliruegas
13,051 posts
 
Dear @czarivey : I don't know @scottwsmith  thinking but if I own an Ortofon A-90 I will make my best effort for this little gem can shows at it best even if some one gave me the A-90 as a gift and if I can't because I don't know how to do it or have no money for make changes in my system then I will put the cartridge on sale for it can find out a better place to " sing ".


Regards and enjoy the music,
R.




erik_squires
16,052 posts
 
Hi Scott!

The main reason for a SUT is to give the preamp enough voltage. It sounds like both are already too much, so technically you don't seem to require one.

If you just like the sound, to warm up what you hear, you may want to use a 1:1 isolation transformer.  Jensen makes some of the best. 

You could also build an L Pad attenuator. after the transformer. Even using the most expensive "naked" Vishay resistors you could do it under $50.

Best,

Erik
oregonpapa's avatar
oregonpapa
4,867 posts
 
rauliruegas ...

With all due respect, I think we may have a language problem here. I wasn't commenting on whether the A90 is a better cartridge than the ART-9. My comments were directed at which cartridge is a better match for the ARC PH-5. True that I haven't heard the A-90 in my system. It may or may not be a superior cartridge, but if it doesn't work with the pre-amp,  what good is it? 

Take care ...

OP
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