Amtron - Guitar Fuzz Box UK857

Post by **modman** » 11 Mar 2008, 15:41

EDIT April 2021: Full article in PDF:

Amtron UK857 - Guitar fuzz box.pdf: (392.05 KiB) Downloaded 43 times

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http://filters.muziq.be/model/amtron/uk857

Analogguru told me these were sold as DIY kits in the 70s by an Italian company, as you can see from the pics on Discofreq's site above. I found this

: Amtron - Guitar Fuzz Box UK857 schematic

with a 741!

:

Hardly find anything on Amtron on the web because a lot of other companies seem to have assumed this quite funky name!

Bernardduur · Post by **Bernardduur** » 11 Mar 2008, 16:16

The schematic appears to be Dutch I guess as Uit for out is not used in many languages

analogguru · Post by **analogguru** » 11 Mar 2008, 16:51

I think the Name was derived from AMateur-elecTRONics.

The company was:
GBC (G.B.C. - Gian Bruto Castelfranchi); Milano - Via Petrella, 6.

In the second picture at discofreq´s you can see below the unit the typical instruction-manual which came with the kit.

The kit itself came blister-packed and looked like this:

Some kits were:
UK 65 - Transistor Tester
UK 261, UK 262, UK 263 Electronic Drums
UK 460 - FM-Signal-Generator (1973)
UK-505 - Tube Radio (1967)
UK 780 - Metal Detector
UK 850 - Electronic Keyer (for Morse)
UK 935 - Wide Band Amplifier

Here you can buy/get some Amtron schematics:
http://web.tiscali.it/techservs/formskem.htm

analogguru

MoreCowbell · Post by **MoreCowbell** » 11 Mar 2008, 17:51

THIS is why I love coming to this forum...I consistently find interesting things, and the vintage circuits that get "dug up" are especially cool.

Thanks guys.

Dirk_Hendrik · Post by **Dirk_Hendrik** » 11 Mar 2008, 18:09

An input cap wouldn't be an unnecessary luxury.....

As well as not using the virtual ground (half vcc) as jackground too...

analogguru · Post by **analogguru** » 11 Mar 2008, 23:26

MoreCowbell wrote:THIS is why I love coming to this forum...I consistently find interesting things, and the vintage circuits that get "dug up" are especially cool.

Thanks guys.

Wait, wait, wait...
You don´t have the mechanical details, but here they come:

tcobretti · Post by **tcobretti** » 13 Mar 2008, 01:51

AG, that is very cool indeed. You guys certainly unearth some weird stuff!

toneman · Post by **toneman** » 13 Mar 2008, 02:50

INDEED they do

DiscoFreq · Post by **DiscoFreq** » 15 Mar 2010, 20:54

I just received NOS kits of this one and an Amtron Guitar Preamplifier. I'll do my best to post information once I have some time (probably after Frankfurt

)

tinypedals · Post by **tinypedals** » 24 Jan 2011, 18:58

DiscoFreq wrote:I just received NOS kits of this one and an Amtron Guitar Preamplifier. I'll do my best to post information once I have some time (probably after Frankfurt )

Any updates ?

DiscoFreq · Post by **DiscoFreq** » 24 Jan 2011, 19:38

Still in a closed box

I just received another Amtron Fuzz last week:
http://www.effectsdatabase.com/model/amtron/uk854

The complete kit with papers, except for the PCB. I just have to scan the papers when I'm at my job

DiscoFreq · Post by **DiscoFreq** » 25 Jan 2011, 16:56

I added 2 PDF's to this page:
http://www.effectsdatabase.com/model/amtron/uk854

DiscoFreq · Post by **DiscoFreq** » 26 Jan 2011, 07:38

BTW, comments about that circuit are welcome

RnFR · Post by **RnFR** » 26 Jan 2011, 12:21

looks similar to the fuzz face- biasing is a little bit different, though. the large 330K feedback resistor and large collector resistors probably give it a more gated sound, but with the addition of the 100K feedback bias resistor on Q1 that's not found on the fuzz face, I can't be sure. it's definitely worth checking out, and probably sounds more interesting than the fuzz clipping the rails of the op amp above. thanks for sharing!

jrod · Post by **jrod** » 26 Jan 2011, 14:24

Thanks for sharing all the info, discofreq!

Yeah, that 100K bias resistor is different for that type of circuit. Well, that I've seen anyways.

kaycee · Post by **kaycee** » 27 Jan 2011, 09:44

Thanks for sharing discofreq

That DIY build looks so cute in its little project box

f_p · Post by **f_p** » 05 May 2013, 16:31

Hi guys!

I found locally this old device which is some kind of fuzz with rca inputs and outputs. I don't know the manufacturer since it's not written anywhere, it only has two pots marked "attack" and "level" just like a tonebender. I still haven't bought it (but will sure do one of the next days since it's really cheap), but I asked the seller to send me some pics of the board. I know these aren't great pics at all, but could someone of you recognize which kind of fuzz is this? Thanks!

mictester · Post by **mictester** » 05 May 2013, 20:11

How many transistors does it have?

agoldoor · Post by **agoldoor** » 06 May 2013, 03:45

Hey... I'm curious too about this one. So I posted your thread and photos over at the DAM forum, as those guys have certainly seen their share of fuzz:
http://stompboxes.co.uk/forum/viewtopic.php?f=6&t=14711

f_p · Post by **f_p** » 06 May 2013, 09:17

Thanks for the support!
I don't know how many transistors it has, but as soon as I'll have it (so in a couple of days) I will post better pics!

Amtron - Guitar Fuzz Box UK857 [schematic]