# Supro Taurus Schematic? Amp techs?



## rpurdue (Nov 9, 2011)

Anyone have a schematic for a 1967 Supro Taurus/Gretsch Superbass head? I just picked one up and although it sounds great i'd like to maybe get a little more gain out of it. It stays super clean even on 10. Also, it needs a 3 prong plug installed. Any info or help is appreciated. Also, any good amp techs in Manitoba or Alberta?

http://www.thegearpage.net/board/editpost.php?do=editpost&p=12248452


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## Cups (Jan 5, 2010)

I checked schematic heaven and found nothing. Does it have a model # too?


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## Soultone (Jan 3, 2011)

Try this link: http://www.valcopages.com/Schematics.html


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## Cups (Jan 5, 2010)

The quickest and easiest way to up gain is to add cathode bypass caps. I don't see a layout but follow pin three and pin 8 of the first preamp tube. It should lead to a resistor to ground (according to the Gretsche schem I found the resistors are 2k2) Cathode bypass caps up gain at certain frequencies, so the higher the capacitance the higher the frequency being "gained". Start with the industry standard 25 uf (or 22uf) and go lower from there. 

There's also an elaborate filtering network between the two preamp gain stages that looks to be stealing signal. But I don't think you want to experiment with that.

If the bypass caps don't quite do it for you you can change the cathode resistors too. Changing the first stage Cathode resistor to 1k5 will up gain and probably warm things up a bit in the process. 

Hope this helps.


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## parkhead (Aug 14, 2009)

all the gain is being thrown away at the input 
the grid leak resistor is 220k industry standard is 1meg 
there is also a capacitor pulling top end off at that junction 

locate the 220k replace it with 1 meg & lift one leg of the cap & give the amp a listen 

it should rock much harder 

p


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