Done lots of reading on this forum and enjoyed the valuable comments. Hoping someone can help me with a specific issue.
Firstly my system: Yamaha P-500 direct drive TT with Nagaoka MC10 MM cartridge (just getting into it, so nothing fancy). Meridian 551 integrated with MM phono card, B&W DM6 speakers. My interconnects and speaker cables are generic (basic).
Problem? I was previously using a Rega Mira 3 with its internal phono stage. The sound to me was excellent, perhaps just lacking some bass. When I switched to the Meridian, the sound with other sources (eg CD) improved to my ears. However on LPs, the sound was extremely baffled and somewhat distorted.
Going through some troubleshooting with a mate, we discovered the Meridian takes MM inputs up to 3mv, and my cartridge had an output of 5mv. That seems strange, because 5mv does not seem uncommon. So we have installed a makeshift attenuator on the inputs to bring the level down.
This has cured the problem, but I still have two issues.
1) There is a hum at normal to loud listening levels, weather the TT is spinning or not. I have tested the setup using a cheap Jaycar (ie Radioshack-style) phono stage and there is no hum, nor was there with the Mira 3. Nothing else in my setup has changed, and the TT is grounded well to the amp.
2) The sound still is nowhere near as it was with the Rega.
The obvious solution is to go back to a Rega! But I love the sound of the Meridian with my other sources and would like to know if anyone has any advice for me.
You can use the Rega phono section and run from tape out on the Rega integrated into tape in on the Meridian. However, I think I would try to resolve this problem by dealing directly with Meridian. The Meridian is "better" gear than the Rega and I would want to exploit the capabilities of the better equipment. Since a phono cartridge is not a typical source where the signal is generated by a device running on 120VAC it is not uncommon to have grounding problems when only the pre amp changes. Meriridan will have the most experience solving this sort of issue with their own gear and I would rely on their expertise to get the best out of the superior equipment they provide.
I thought I would update anyone interested in knowing the update.
We have fashioned some more permanent attenuators at the RCA input to the amp. This is just a small resistor.
The result is that the hum is now non-existent. The system is now quieter than it has ever been. So the hum must have been from the board arrangement that we made up as a trial.
The sound is now about 90% to what I think it should be given the components. Some music (eg Kraftwerk Man Machine) doesn't sound up to scratch, but my Jazz LPs sound fine. I find it hard to verbalise my musical experiences but I could probably say it has less impact than I'd like.
My next step I'm thinking is either a high-output MC cartridge or a turntable upgrade altogether (ensuring the cartridge is =<3mv.
