2. analog
  3. 1358098541

Cartridge gain overload - please explain

I am using a Lyra Delos on a JA Michell tecnodec, a Whest .30R phono stage,
an ARC LS25 linestage, ARC VT100 amp, and Rockport Mira Monitors.

I recently added the Whest to get more gain because the ARC PH3SE with 54dB was not enough, especially because the LS25 gives just 12dB of gain to single ended sources. By switching to the Whest, I was able to get more gain right from the phono stage, and also an additional 6dB from running balanced into the LS25.

Because I was coming in from a under-gain situation, I started with the Whest set to 66dB, thinking a bit more is good, and I could just turn the volume knob lower on the LS25. But there was that record pop / loud static discharge sound which was actually cartridge gain overload. When I changed the gain settings to 60dB, the problem ceased.

My question is, why does this happen? Whats wrong with an extra 6dB from the phonostage and just a little less output from the linestage to compensate? In my mind, that seems like it would work fine.

I would like to know more about this. Perhaps there will be even a benefit if I switch down to 55dB? But that seems counter intuitive, because I was getting too little gain before and I had to really ramp up the volume on the line stage, which caused a lot of noise.

thanks,
Mark
marktomaras

Showing 2 responses by marktomaras

marktomaras OP
544 posts
 
Hello All,

Just a point of clarification. The ARC LS25 has variable gain, and had more gain available to balanced inputs. Selectable for each input: 18db, 12dB, 6dB Balanced output. (12dB, 6dB, 0dB SE output)

So, that is why I get more gain with the Whest, running balanced, before I even boost up the gain on the phono stage.

I agree with many of you, I think the distortion is in the phono stage when the gain is set too high, as I experienced at 66dB. Now i am at 60dB, and it seems fine. I also am pleased with where my volume knob is at 60dB.

The other night, my wife and a couple of friends were having an epic listening session, and the music was definitely loud. At the loudest point, the volume was getting very close to 3 o'clock. I'd imagine that I will very rarely ever go louder.

So, do you think I should be trying 55dB to get less distortion, and risk the need to push the volume knob higher, or stick with 60 dB? If I switch from 60 to 55, what should I be looking for sonically?

thanks!
Mark
marktomaras OP
544 posts
 
Progress. Yes I did indeed. The whest allows me to get 6 more dB out of the LS25, so off the bat, it's a help. I then tried 60 and 66 dB on the whest. 66 gave me distortion/overload, so I dropped to 60. Then, to see if I was still getting some less obvious distortion at 60, I dropped it to 55. This setting may not give as much gain as 60, obviously, but it is still a jump in output over the ARC's 54 single ended. I may go back up to 60 eventually. Right now I am playing with loading. 100 seemed a wee bit flabby, so I am now listening to it at 200. Actually, I am having a tough time hearing the loading differences. I have an ear doctor appt soon for reasons other than ohm load sonic difference detection, but I will sure test loading again after I get back from the doc! Any advice on loading?
More to discover