I suggest switching to a low-output mc cartridge to better match the gain level of your phono stage. IMO high-output mc cartridges never sound good!
Phono stage gain too high??? Should I return it??
Just purchased a used ARC PH-7 and am wondering if it is defective as the gain seems awfully high. I have it running into an ARC LS-27, and it's fed by a Project RPM10 with Sumiko BlackBird Hi Output (2.5mV output, 47K ohm). I was expecting it to be the lowest gain input in my system, but it's so loud, I cannot set the LS-27 anything over 7/8 (my digital input, Schiit Bifrost is in the 12-16 range), and it does not go soft enough for late night listening.
The only way I can get it to a reasonable gain level is to set the load at the lowest setting (100 ohms), which totally squashes the dynamic range.
The seller gave me a 30-day return window. I really like the PH-7 in terms of tone, but is something wrong with it?? It's rated at 57.5 db gain which is modest by most standards, I think. I have other phono stages rated at 60+ db and in my system, they exhibit LESS gain. How is this possible??
The only way I can get it to a reasonable gain level is to set the load at the lowest setting (100 ohms), which totally squashes the dynamic range.
The seller gave me a 30-day return window. I really like the PH-7 in terms of tone, but is something wrong with it?? It's rated at 57.5 db gain which is modest by most standards, I think. I have other phono stages rated at 60+ db and in my system, they exhibit LESS gain. How is this possible??
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The gain of the PH7 is fixed at 57.5db, which in my view is a bit high for a high output cartridge. However, on your LS27 line stage you can configure the gain for each input individually ( Low, medium, high). My suggestion would be to set the phono at 47k and reduce the gain of the phono input on the LS27 linestage to the lowest possible - low. Furthermore be aware that the single ended output ( RCA ) has half the gain of the balanced ouput ( XLR ), so this can be factored into your set up options.. |
I agree with the above post. 57db is too much gain for a the high output cartridge you are using. You should return the PH7 or replace the BlackBird with a lower output cartridge. Another option is to add an attenuator between the PH7 and the LS27. http://www.schiit.com/products/sys |
There’s nothing wrong with the PH-7 other than compatibility with your cart. I have the PH-7 and the gain works well with .5mv to .8 mv. The 60+ dB rated phono pre you mention is for the MC setting. You’re no doubt using the MM setting which has much less gain plus the recommended 47K load for the Blackbird HO. |
That is odd how your 60 dB gain phono stage has lower output than the 57 dB ARC. My guess is that your other phono preamp has a low input resistance, perhaps 100 ohms or so, and the ARC has a 47K input load. I am not familiar with your cartridge, but if if is intended to have a 47K load it may have much less output into a 100 ohm load. That said I have always regarded the ARC phono preamps as an aberration in terms of gain. They have far too much gain for a typical MM cartridge and barely adequate gain for a low output MC. But gain suitability is very system-specific. In my system right now I have a LOMC (.3 mv) feeding a SUT and phono preamp with a combined gain of 60 db with a passive attenuator (no gain) instead of an active linestage, and I have plenty of gain. |
Thank you all so much for the thoughtful responses. Just a couple more details: 1. I DO have the LS27 set on LOW gain for the phono input, and configured that way the Phono has higher gain than the Digital which is also set on LOW. 2. I am a relative noob and got the Blackbird in a package deal and am loathe to sell it, esp given how much cartridges of that caliber cost. All that said, I am just loving the ARC tube sounds, it blows away everything SS I have tried. |
@tswei99 I DO have the LS27 set on LOW gain for the phono input, and configured that way the Phono has higher gain than the Digital which is also set on LOW. By changing the CD input to medium/high you can at least equalise the 2 inputs. Are you running single ended or balanced interconnects between your LS27 & power amp ? If you are running balanced you can reduce the gain by changing to single ended interconnects. Have you checked your power amplifier to see if it has adjustable input sensitivity to reduce the overall system gain. This is another way of getting your preamp volume into its optimal range, once you have equalised the inputs. |
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These are the substitutes for a 6922 tube. They are all the same gain! https://www.tubedepot.com/t/tubes/preamp-tubes/6dj8-6922-ecc88-e88cc-cv2492 |
Yogiboy How about this one https://www.tubedepot.com/products/6sn7-to-6922-adapter then use 4ea 6SL7 ? Good Listening Peter |
Do not try to change tubes to change the gain. The circuit is optimized for a particular tube- the 6922/6DJ8. A higher output cartridge should not be used with low impedance loads like 100 ohms. I don't think low output cartridges should be either but that is a different conversation. The point is that the loading is not how you adjust for gain. It has a different function altogether. You have several options. One is to go to a lower output cartridge. Another is to use a passive line section instead of active. IME that really works best if you run short cables from the line section to the amplifier. I'm not a fan of passive volume control systems as in nearly all cases I've seen an active sounds better, but passives can work if the cables are kept short and care is taken in the setup. A third option might be an input level control at the amplifier input. |
tswei99 All to common problem these days TOO MUCH GAIN! This was why my product was so successful for me. Sell the ARC LS-27 and pocket quite a bit, and purchase a passive which as Ralph (Atmasphere) suggested, but get this one which also gives you two types of active modes with low gain, one tube and the other solid state, you can switch between the three on the fly, it's remote with probably the best volume pot you can get in it (128 switched relay) it's also xlr or rca. All for $699. http://www.schiit.com/products/freya Cheers George |