Tape heads on a Dynacord Super62

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Noth

Active member
Joined
Nov 19, 2021
Messages
37
Location
Fr
Hi,

This is a folluw up of Capacitors on a Dynacord Echocord Super62
And Dynacord Echocord Super 61 tube tape echo replacement playback head

So, the preamp section of my Dynacord Super 62 works fine now.

Now, it appears that all 2 play heads and 3 record heads are cut (unsoldered and tested with an ohm-meter).
Worse, I did actually repair one of the record head that was also cut and.. it's dead again.

Play heads
As far as I can remember, at least one of the two was partially unsoldered. Thus on wire was having fun very next to one of the tube pin.
I supposed that, at some point it went in contact with high voltage and died.

Record head
I suspect that the circuit is sending too much voltage/tension which ends up burning the wire.



I'm lacking a bit of methodology here, what should I do ?

I'm thinking replacing the heads with a fixed 440 Ohm resistor and measure the tension/voltage across it.
Does that makes sense?
What are regular values that I'm supposed to expect (I'm totally unfamiliar with tape circuits)?

Once everything looks fine, i'll have to fixe all those heads.
Since it's quite hard to find replacement ones, I'm thinking about two options:

1. dismount the tapes heads, unwire, resolder and rewire
2. dismount the tapes heads, unwire, rewire with a brand new wire

Does it make sense? Is that a "regular" practice?
I'm not looking for a super crazy audio quality (if I need a hi-res delay, I have other options)

Thanks for any advice!
 
I test tape heads by attaching them to a hi-gain mic preamp and dragging a piece of recorded tape over them.

Alternatively, I've used a known-good tape head to inject signal, just holding these together with a rubber band. Any signal generator or PC headphones output has enough signal to drive this.

I tried doing frequency plots with two heads, but that's not reproducible. The slightest shift in position wrecks the results. I don't do it often enough to build a jig...
 
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