Guyatone - Rolly Box

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Bernardduur
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Post by Bernardduur »

Got this one in for repair. Cool little box that looks like it was placed on the bottom of the sea, yet the inside was clean. Fixing points were the switch (which was completely dead) and the ELCO's.

The LED on this unit just powers up when connected to the battery. No DC jack in this unit. The Vox 1900 phaser is claimed to have the same PCB. All opamps are sanded off BUT not really well so you can spot the LM1458 markings. The can opamp is worked with black paint but still the 741 is visible. All FET's are 2SK30A's. The Depth potmeter has a switch in it to remove the feedback path or dial in the rigth amount of feedback. PSU is still weird...... My guess is that they wanted a + and - voltage to control the opamps and use ground as the reference.

Here's what it looks like

Schematic:
Guyatone - Rolly phaser.JPG
'No more....... loud music.......'
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Dirk_Hendrik
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Post by Dirk_Hendrik »

Rather odd to call the net that contains the LFO signal that drives the Fet's "Vref" ;)

And how about a multimeter to measure those zener voltages?
Sorry. Plain out of planes.

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Bernardduur
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Post by Bernardduur »

:)

It was a draft when I made it..... I kept it there!

I'll see if I can measure those voltages......
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Dirk_Hendrik
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Post by Dirk_Hendrik »

And where do the sleeve connections of the jacks connect to? To that virtual ground net?
Sorry. Plain out of planes.

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Bernardduur
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Post by Bernardduur »

I've added all comments;
Guyatone - Rolly phaser.JPG
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

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