Wheatstone TV-600 Mods

Contact me at: fenris (at) fenrisaudio.com

My name is Fenris Wulf. I run an analog recording studio in California.
A few years ago I obtained one of these undervalued consoles, and since then I've learned just enough about electronics to start modifying it.

These mods are fairly easy, inexpensive, and make the console drastically more useful for studio recording. These consoles are very well-designed, easy to maintain, and have a big, clean sound, but they have  some odd design choices. The mic preamps are too sensitive, all the EQ's are post-insert, and all the EQ's are bell filters (no shelves on either the mono or stereo modules).

Wheatstone consoles from the early 1990's all have a similar design. These mods should work for any console in the TV, SP, or MTX series, as long as you have the schematics so you can find the equivalent circuit points. If you have difficulty, you can emal a scan to fenris (at) fenrisaudio.com and I can probably help.

Warning! Wheatstone consoles from the 1980's have problems with the grounding and the summing bus, which causes noise and distortion. They worked out the problems by the 1990's. The TV-600 has the best feature set. The TV-1000 has a few additional features, but it uses surface mount construction and is probably not a good candidate for extensive modding.

If you have your own ideas for Wheatstone mods, feel free to send them to me and I'll post them on this site.

Our Wheatstone console is a work in progress, and I'm planning additional mods  in the future. In order to expand the number of channels and groups, I may design a custom interface card that routes all the internal buses to an external mixer (a radio broadcast console would work well for this). The group buses and stereo buses are already balanced; the Mix-Minus buses and Aux buses are unbalanced. The Mix-Minus buses can be turned into additional groups.

We purchased the console from Kronos Recording in Burbank, CA. Kronos may be commissioning various custom modules for their Wheatstone console in the future.

I am NOT a trained electrical engineer, and I developed these mods by trial and error. I thoroughly tested all the mods listed here, but I may have made inadvertent errors in the documentation. Wiring or soldering mistakes can lead to ultrasonic oscillations or DC in the output of the console, which can damage equipment that is connected to it. I am not responsible for damage to your console or other equipment. Proceed at your own risk!!!

If you have any broken channels, test the mods on them first. These mods involve hacksawing and drilling. It's going to be ugly, and you're going to make mistakes.

I ordered most of my parts from futurlec.com. Be advised that if an item is out of stock, they might neglect to tell you. Check to see if your order has shipped; if it takes longer than 1-2 weeks, contact them and ask if any items in your order are out of stock.

You should have basic soldering experience before attempting these mods, and the proper tools including soldering iron, desoldering iron, multimeter, etc. When adding jumper wires to the board or connecting extra pots and switches, you should orient the stripped end of the wire perpendicular to the board and use an adjustable clamp to hold it against the solder point. Keep the solder well away from adjacent solder points and ground planes (large conductive areas on the board). Any errors will lead to short circuits and no sound. Some of these mods involve unsoldering one end of a component and connecting a wire to it; you should use heat-shrink tubing to prevent short circuits.

Some of the mods require cutting traces on the board. I found that a miniature flat-blade screwdriver worked the best and was less likely to slip and cut the wrong trace. I gradually scratched away at the point I wanted to cut, instead of trying to cut it all at once. Some people advise using a grinding tool, which I haven't tried.

You might label the new controls by putting plastic tags under the nuts, or make a laminated "cheat sheet" and attach it to the board. Don't use adhesive labels, they will eventually wear off.

And here are the mods...

Mono Channel: Reduce Minimum Gain of Mic Preamp
Stereo Channel: Convert EQ from Bell to Shelf, Add Additional Frequencies
Mono Channel: Convert EQ from Sweep to Fully Parametric, Add Bell/Shelf Switch
Mono Channel: Make Filters Pre-Insert
Stereo Channel: Add Width Control for Effects Returns
Stereo Channel: Make EQ Pre-Insert, Make Mid Band Post-Insert
Stereo Channel: Convert to Mono Channel
Mono and Stereo Channels: Left, Center, Right Switches

And one more ... in the picture at the top, you can see that I moved the talkback mic forward. I drilled a hole in one of the blank fader panels, mounted the gooseneck to it, and ran the mic cable back through the slots in the bottom of the frame to the talkback module, with a balanced connector right under the blank panel so it can be removed.