Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Vintage Gramophones and Phonographs

Forum home - Go back to Vintage Gramophones and Phonographs

 HMV TA, TC and T9 gram chassis and magnetic cartridges
« Back · 1 · Next »
 Return to top of page · Post #: 1 · Written at 9:13:58 PM on 7 January 2024.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2370

This very common and long-running series has a very interesting (and seemingly undocumented) feature that I found when I was looking to fit a magnetic cartridge to my Y2-D3.

Even though units with these chassis were fitted with ceramic cartridges, it seems you can just drop a mag cart in with no changes. You don't need to add a preamp or modify the circuit in any way.

I wondered why the circuit is the way it is so I modelled it in LTSpice, using the Shure analogue model for the mag and the accepted ceramic model of a voltage source in series with 800pF.

It checks out! I get the same output for both types, flat from 100Hz to 5kHz at least.

It's a disarmingly simple circuit idea that just uses shunt current feedback in a novel way.

What gets me is why HMV didn't tell anyone about it!

« Back · 1 · Next »
 You need to be a member to post comments on this forum.

Sign In

 Keep me logged in.
Do not tick box on a computer with public access.