Convert cartridge output voltage to db gain

Al, you are right, I misread Hdm's first reply when he said "I'm with Kal above", I read "I am Kal from above". I thought maybe Kal had two monikers. My mistake, I apologize to Kr4 and Hdm. No, 2.5V does not overload the VAC at all.

Darkmoebius, thank you for the compliment on my system and yes it does sound pretty good, even after the downsizing of '08. Thanks also for the VAC manual link, but I do have the VAC manual, I just misplaced the Walker manual. The specs in the VAC Avatar Super manual do not give the line and amp section gain levels like the Avatar SE did. FWIW, the VAC replaced a stock ARC REF 3 preamp and a highly modified BAT VK-75SE by Bob Backert of RHB Dezigns running fully balanced.
My cartridge is the low output version of the ZYX UNIverse S-SB, same as listed in my system at AA.

I have tried the built in MM phono stage of the VAC using a cheap SUT with the same ZYX cartridge. The sound was pretty good, but not in the same league as the Walker phono stage. I would not expect the inboard phono stage of a $6500 integrated amp to beat a $6650 outboard phono stage though. I know, to be fair I probably should have tried the VAC with a better SUT, but I was nervous about spending big $$$ on a SUT without hearing it in my system first. Thanks again for that calculator, I saved it in my favorites.

Thanks for all of your help too Al, you bring a wealth of knowledge to these forums that is very refreshing. I think I'll try to give Lloyd a phone call tommorrow. I still think I'm best to:

a)check the DC offset in the Walker (no coupling caps, Lloyd believes the best cap is no cap). If that doesn't help then...

b)change the line stage tubes in the VAC.

Hopefully that will solve my problem, if not, then I will probably proceed to looking at higher output cartridges.

Happy Holidays,
John

John,

You should be aware that ZYX's output specs for their MC's is not based on the industry standard test record. I lost the reference (I think Nsgarch posted it here once), but from memory you need to multiply ZYX's stated output by ~1.4 to get a spec that's comparable to most other cartridge brands.

For a .24mv UNIverse, the actual output using the industry standard test record would be around .35mv.

FWIW...

Thanks Doug, I don't know if that makes much difference though. It does increase the output voltage from my phono preamp from 0.48V to 0.58V, but that's a relatively small increase compared to the 2.5V that my CDP outputs.

I have read about differences between the two industry standards (CBS and JVC???). I never really delved into it though because the difference seemed rather minor when you're considering the difference in a 0.24 mV output and a 1.25 mV output cartridge. If I do wind up looking for a new cartridge, I can't see considering one with less than a 1.0 mV output regardless of measuring standard.

Cheers,
John

Hi Jmcgrogan2,

I don't have time to run through some of the likely great responses you received on this thread. Holiday activities beckon (happy holidays to all).

In case some of the above advice has you stumped, , I dleve into this issue in a thread on my forum (in the Electronics forum in the Setup and Tweaks section):

http://www.galibierdesign.com/phpbb/viewtopic.php?f=13&t=35.

There, you'll find a real-world example showing how to use an online dB calculator that I link to. The calculator allows you to go both ways - from dB to step-up ratio as well as the reverse.

Hopefully, this isn't redundant, and if it is ... accept my apologies.

Cheers,
Thom @ Galibier

Thanks Thom. Darkmoebius posted a calaculator on his first response on this thread too, It's a little different from yours, but both have their strengths, thank you.

Happy Holidays to all,

John