18-08-2020, 03:21 PM
(This post was last modified: 18-08-2020, 03:40 PM by Mike Watterson.)
Four 1N60P or 1N4148 or Schottky signal diodes is a an easier to do balanced mixer if you know how to wind the transformers. The choice of diode and if needing matched depends on the application.
An SAA612 is far better and has an optional oscillator with regulator. It can do AM by unbalancing the DC at the input.
The 7360 is a far superior mixer to a Heptode, Octode, Hexode part of an ECH81, 1j37b or 1j42a, unless you want 12V operation. The ECH81 *IS* an ECH83, so works off +12V to 14V HT, though grids need to be at +1V.
The 6BN6 is a wonderous thing and comes in 3V, 4V and 12 V nominal heaters as well as 6.3V 300mA series/parallel. But it's too specialist as a mixer. It can be used for an Stereo Decoder (feed with 19 kHz via filter to g1 and 38 kHz to Quadrature electrode via a high pass) or FM limiter detector, or possibly a sync separator. Grundig did a single pentode valve stereo decoder using also semiconductor diodes. The EQ80 was from the EQ40 and was a solution looking for a problem. Not cost effective compared to any other solutions.
An SAA612 is far better and has an optional oscillator with regulator. It can do AM by unbalancing the DC at the input.
The 7360 is a far superior mixer to a Heptode, Octode, Hexode part of an ECH81, 1j37b or 1j42a, unless you want 12V operation. The ECH81 *IS* an ECH83, so works off +12V to 14V HT, though grids need to be at +1V.
The 6BN6 is a wonderous thing and comes in 3V, 4V and 12 V nominal heaters as well as 6.3V 300mA series/parallel. But it's too specialist as a mixer. It can be used for an Stereo Decoder (feed with 19 kHz via filter to g1 and 38 kHz to Quadrature electrode via a high pass) or FM limiter detector, or possibly a sync separator. Grundig did a single pentode valve stereo decoder using also semiconductor diodes. The EQ80 was from the EQ40 and was a solution looking for a problem. Not cost effective compared to any other solutions.
