Hornby (Skewes, JHS) Selectatone T.B.2 (Treble/Bass Booster)

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

Gut shots can be found here: http://www.solidbodyguitar.com/Hornby.htm

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Drzeus
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Post by Drzeus »

I can play the aqualung lick,and some great shots EW! As the main JHS guy,are you going to be doing a schematic in the future? Thanks
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Post by Electric Warrior »

I'll give it a shot but many details can't be seen in the pics..

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Post by Electric Warrior »

Here's how I see it:
selectatone.png
any objections?

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Post by Electric Warrior »

a bit neater:
selectatone.png
The resistor in the bass section must be 1k of course (like in the Hornby Skewes Bass Booster). I can make out the red band clearly and the other two are dark.

I believe the two missing capacitors are most likely 0.1µFs (right - like the Bass Boost :mrgreen: ). We can be pretty sure about the one on the collector. The Treble Booster has 0.001µF there. 0.1 and 0.001µF in series isn't that much lower than 0.001µF.
The input cap might be more debateable..

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Post by Drzeus »

Not from me EW!.I'll knock one up,see how it flys?.You're a star!
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Post by Electric Warrior »

Well, it's just a Hornby Skewes Booster with switchable output section. :D

The bias resistors are different from the silicon version of course, but we already knew that from the germanium Treble Booster pic. The value that's new here is the the 100k from base to -9V. That one wasn't visible in the other pic.

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Post by Drzeus »

That's the beauty EW.I've built a silicon booster with a 4061 in,and a switch for the debated input caps,but never a GE version.It's like you've given me a jigsaw piece i had missing!
Cheers
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Post by Drzeus »

Is the 1k/0.1uf to ground,seperate to the treple switch,or joined to the 100k to ground?
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Post by Electric Warrior »

good question.. it's hard wired to ground.. but the 10k/1k joint and the 0.001 probably aren't.. I'll update my schematic..

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Post by Electric Warrior »

here you go:
selectatone.png
what a stupid mistake.. :mrgreen:

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Post by Drzeus »

Not a mistake,an update.Thanks EW
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Post by Electric Warrior »

your post subjects are funny :mrgreen:
Aldi?

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Post by Drzeus »

Aldi number 1 dude!The quality of german sausage and other meats,also dutch like frikandellan,are much preferable to the mechanically seperated twine and cereal we get from sainsburys.Cheaper too.DPDT on the output network?
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Post by Electric Warrior »

Funny how cheap Frikadellen are the one thing I wouldn't buy from Aldi :D

DPDT indeed :thumbsup
They used DPDT switches for on/off on the seperate Treble and Bass boosters, too, but didn't wire them up for true bypass.. same deal with the Rangemaster. Disconnecting the battery took priority...

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Post by Drzeus »

I lived in amsterdam an zwolle for a few years,and got a thing for those glass holders,u put a few guilders in an took a frikandelllan,them went in to get some frite saus
lekkerer!
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Post by RnFR »

I think I spent 100 bucks in those things in 3 days. :lol:

nice work on this one. I'm gonna mark it solved. :thumbsup
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Post by Electric Warrior »

well, nearly.. anybody know the guys at solidbodyguitar?

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Post by Drzeus »

It'd be good to get the worked up schematic to them?
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Post by Drzeus »

Sorry 'bout this.My edit function seems to go after a minute?.So EW,the cap off the collector but before the t/b network,is 0.1uf to your mind?.And the input cap the same?.Thanks again mr.jhs!
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