Page 3 of 3

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 23 Nov 2014, 21:58
by modman
LucifersTrip wrote:
sinner wrote:Nice, I see nothing (cheep shit screen I have here).

It's low gain transistor 10-40hfe... and NPN indeed


according to this, it's a power transistor....which is doubtful
http://transistor-spravochnik.ru/descri ... n5580/5047

I built the ge version a while back with this schematic:

[ Image ]

It's a smooth, thin & very trebly (look at in/out caps!) fuzz with very good sustain. If you don't like the mushy-ness or darkness that you can get with some ge FF's, this is for you!

At the time, I had no idea what Q2C voltage was supposed to be, so I have an external pot. I believe Solidhex noted that it should be a bit higher than a Fuzz Face...but how high? Were there voltage measurements from an original in any threads here....

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 23 Nov 2014, 22:08
by modman
More 60s Vox SFT transistor Tone Bender guts

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 23 Nov 2014, 22:14
by modman
And here's a third one with still other caps

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 23 Nov 2014, 22:44
by sinner
Yep. They comes in all sorts of different flavours cap-wise

I got it covered and documented here

The ones ain't know shit about are the ones with silicon transistors. You know, the same board's layout but with silicons. Not the later ones with clipping diodes

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 24 Nov 2014, 11:51
by ringworm
Regarding the silicon transistors, does someone know 'The Captain', to ask him? If the silicon gut-shot is indeed his... http://stompboxes.co.uk/forum/viewtopic.php?f=6&t=171&hilit=sound+like+dog+shit&sid=8a36b8a141b7fd174ebbde86d62cc9b5&start=10#p12741
I definitely think one is 2N5550 but I can't read the other.

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 24 Nov 2014, 12:07
by sinner
I have RE to many DAM and EFE pedals to be brave enough to ask him ;)

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 24 Nov 2014, 14:39
by ringworm
I'm sure he appreciates your attention to detail :wink:

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 26 Apr 2015, 06:47
by polifemo
Got one of these at home right now.

6.1v on Q2's collector.

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 26 Apr 2015, 07:04
by polifemo
Here are some pics

Image

Image

Image

Image

Great sounding unit!

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 08 Mar 2016, 19:07
by The Rotagilla
Question for you guys. RG Keen’s schematic shows a 47k resistor in parallel with the 500k volume pot which (and correct me if I’m wrong) drops the value of the volume pot to 42.96k. Fuzz Central’s schematic omits the 47k resistor and shows a 50k volume pot. My question is this…is there any particular need for the 47k resistor?

Thanks!

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 08 Mar 2016, 22:22
by ljn
Using the 47k resistor in parallel with the 500k volume pot cuts bass. If you use a 50k pot for volume, it isn't necessary.

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 09 Mar 2016, 00:07
by The Rotagilla
ljn wrote:Using the 47k resistor in parallel with the 500k volume pot cuts bass. If you use a 50k pot for volume, it isn't necessary.


That's what I thought, just wanted to check. Thanks!

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 10 Mar 2016, 04:22
by ljn
Glad to help. Just remember that in these fuzz circuits, a smaller value on the volume control will always cut bass.

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 10 Mar 2016, 15:43
by The Rotagilla
Also wondering about the resistor that goes from lug one to ground on the fuzz pot. I've seen schematics with a value of 820r and 8k2, has anyone verified that an 8k2 was ever used or is it a color band reading error?

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 11 Mar 2016, 03:48
by ljn
Every schematic and gutshot I've seen of this circuit has a 820 between lug 1 of the attack control and ground. If you tried a 8k2, it would be so distorted that it would barely pass signal (if at all ).

Re: VOX (JEN) Tone Bender - circa 1966 - 197(?)

PostPosted: 04 Aug 2017, 12:57
by LaloFP
Hi!

So.. is there any news about the Si transistors? Gains?

Some mension 2n5550 or 2n5551 for one, but dont know about the other.

Thanks!

:horsey: