'Plate Amplifier' Design

Muckerbarnes1 wrote: Class D JC... tut tut, such language to us anal ogue blokes.   I'd still FET it Mik, but then I'm a FET anorak.

Class D????

The original well proven design for the Power Amplifier channels uses Bipolars and it seems like a lot more work to change to FET's..... anyway, FET's run hotter

When first designed in the 1970's, it used 2N3773's
These became very variable as to their Ft leading to only RCA branded devices having to be specified.
After building about 30 channels, changed to the BUV61 (or thereabouts) device without further problems of excessive heating when trying to get full power output at 20kHz.
Farnell - BUV61 catalog page
However the RCA 410, also used by Phase Linear, worked very well for HF versions with minimum 8 Ohm loads

Mik

Edit: add Power Transistor (family) type and Farnell link

Edited by audiomik - 23 July 2013 at 6:48pm

Whilst you, I and no doubt some others on here, may be capable of re-cycling - there are many others who will benefit from a complete design using readily available parts/metalwork.....

Anyway, if I look into my old metalwork collection then there will most likely be very similar. Not much use unfortunately if the salvaged extrusions are manufacturer's specials and not readily available from multiple sources!

Mik

Aluminium box section, and you could split it lengthsways?  Bolt to a plate and mount devices from behind.

Mounting from behind could be a problem. Up front and insulated mounting will always pay dividends.

Earplug wrote: burningbush wrote: Aluminium box section, and you could split it lengthsways?  Bolt to a plate and mount devices from behind. I did try something like that once, but the section seemed to warp once cut. Mik: maybe some pictures of what you´re doing to get a better idea.

On cut box or tube section: there are stresses within the metal structures of these which can cause deformation should the section be cut lengthways.

Will do a Pic or two when I've fabricated the first prototype and run some tests, also when I'm satisfied that it works then perhaps even a CAD drawing.

There will be a bit of delay in moving this project forward, as have a couple of Ch 70 Radio-Mic Receivers which arrived this morning to check for potential Co-Channel Interference prior to the 4G rollout

Mik

I want you to close your eyes and visualise the image to send, we will do the same and see what comes through.  Now concentrate.