Used to run it before I got the SUT. Can’t remember what it was like but I’m pretty sure it had high gain then.
Remember when you borrowed mine, I swapped out v1 and V3…this helped
Oh yeah I did borrow yours, that’s what made me buy one. Hmm
You have too much gain between your MC cart and the line level input on your amp/preamp, that much is clear, but where is there too much gain:
Your MC cart has an output of 0.4 mV (-68 dB compared to 1V), so to get to the notional MM cart output of 5 mV you would use a SUT with a ratio of 1:12.5, about 22 dB gain, but you have been using the 2-7 ohm setting on the HM-3 with 32 dB gain, or 10 dB too much, or about twice as loud as expected. Even on the other setting you have 26 dB gain, which is 4 dB more than required.
The SUT feeds the MM input of the phono stage. The “classic” gain of an MM phono stage is typically 44 dB, i.e. 5 mV to about 800 mV “line level”. Today it can be common to see more gain, to match the CD red book standard of 2V, which would be 52 dB. The EAR data says the MM input sensitivity is 2.2 mV input for 1V output, or 53 dB gain, which is right at the top end of what you would expect from an MM phono stage.
If you notionally want the 1V output, you need 68 dB of gain from your MC, and you currently have 26 + 53 = 79 dB, about 11 dB over
Conversely, the MC input is 0.22 mV to 1V, or 73 dB gain, which would still be 5 dB above the notional 1V output, but 6 dB lower than your current setup.
options:
- use the MC direct into the MC input
- change to a SUT with a 1:10 ratio
- add inline 10 dB attenuation between phono stage and amp
best of luck
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'zacly
Nice work! I bought a -16db pair of rothwells already , I guess they will be too much now? Unless I leave the sut on 2-7
in my very humble opinion having had one for while
1 will be worse, transformers are not the best quality (sorry Tim!)
2 my T10 is a lovely thing (to quote navigator David) - I agree
3 mine are into the 834 and have swapped V1 and V3 (can give you the types if interested)
all works very well
my 2p worth
I cba with valve swapping - will try the attenuators when they arrive.
What is the input sensitivity of the pre?
I still have my living voice SUT at 1:10 that you borrowed.
It’s all going out the window in a bit X
Does sound lovely atm mind you
Input sensitivity for 1V output at 1kHz: 2.2mV (MM), 220µV (MC). Maximum output level: 30V
Does it matter if I attenuate by -16db and try both settings on the SUT? Sounds alright
That seems really quite sensitive.
Where are you putting the attenuators?
I would suggest on the inputs of your power amp.
I would put them there but I don’t have room so I bought the ‘for source’ versions which will come out of the phono. You think -16 will be ok?
Probably as it’s so fucking loud
You should be okay with 16. 10 would have been enough.
I have a pair of 10db rothwells somewhere if you ever need a borrow.
Not used them since I had an AN pre with 23dB gain.
I now have no have no gain in my pre.
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Makes me wonder why people recommended this cart/SUT combo. Apart from sounding great
Might try those 10s one day. The CDP has a -12 on it and it only really gives me a couple hours on the volume dial more
Very good choice of cart and sut. Tis the gain of the pre fucking you up.
Is it okay with CD or whatever digital sort of thing?
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I have a quad CDP 2 which is notorious for having a super high output on it. Woo
I believe rabski ran his into a modded 834p
Seems to indicate the 834 has quite a lot of gain.
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Will see what happens with the attenuators, will try both settings on sut