Elizabethan LZ 34 R2R Checkout

[DMcMahon]

Checked direct line recording into the radio phono input fed from Hi-Fi amp phono tape out.

Records well and plays back very well but need to set the record level (volume control) at a fairly high setting, somewhere around 2/3 of max (no marked graduations for the control) to achieve the EM84 Magic Eye peak fluctuations reaching the red tape section.

But when stopping the recording by putting the Joystick control to Stop (which resets the Play/Record control back to Play), then the music (assuming source music still playing) blares out of the LZ34 speaker very loudly. Also depending upon the music content and the bass control setting the music then can be bass heavy, sometimes almost sounds like the source signal is close to overloading the LZ34 amplifier.

I tried 4 different line music sources (3 amplifiers tape out and 1 CD player) and all gave the same results.

As far as I can see from the schematic, the LZ34 amplifier is acting as a play through amp (unlike many recorders the output stage is not muted) when it is not in Record mode. This is not mentioned in the LZ34 Instruction manual.

There is no spec for the LZ34 radio phono sensitivity but the spec for the Elizabethan Popular 200 & 400 (which have basically the same amplifier electronics) is 200mV.

Recordings done at around 1/4 max record level (minimal movement on the EM 84 display) still give good playback and result in much more reasonable volume level when Recording stopped.

Somewhat suspicious of the EM84 operation, there is no adjustment/calibration procedure, often found on other recorders and there also is no adjustment for the record bias.

There is a discrepancy in the schematic. The HT supply for the EM84 anodes/target is shown connected to junction of R7/C2 (C2 is second filter) but actually connects to the other side of R7 at junction with C19 (first filter) which is 250V.

The anode (Target) load resistor R23 (470k) is dropping very nearly 200V (which seems high to me) with the voltage arriving at pin 9 (and linked pin 7) is 56V. The Popular 200/400 information list the target as 165V.

While operating the Record control knob it fell apart.

David

[Techman]

Originally Posted by DMcMahon

Somewhat suspicious of the EM84 operation,

While operating the Record control knob it fell apart.

Hundred percent on the first one. You'll have to have a play around with its circuit or just accept it the way it is and adjust the recording level accordingly.

On the second one - that's normal for those record levers on the TD10. They're delicate and brittle and need to be operated with care. There's not many survivors now, so time to get the glue out.