Dan Armstrong blue clipper schematic

[geezer15]

Hi,
I have been handed an original Dan Armstrong Blue Clipper circuit board from 1976. The owner wants it in a new box with a foot switch and gain pot (original long gone). I can probably sort it but was looking for circuit diagram to assist.
There seem to be two versions doing the rounds which are similar. The glaring differences I notice are that neither has the correct chip (its a LT081 not a TL071 or 4558). The original only has one diode not two, the two electrolytic caps are 10uF not 4.7uF, it has 10 resistors not 5 or 6 and neither circuit shows the two BC109c transistors on the original.

I might try to draw the circuit myself but its not something I've done before but has anyone come across the original circuit schem. or have any knowledge of changes in the circuit during its production time.

http://circuitdiagram.net/dan-amstrong-blue-clipper-guitar-effect.html/blue-cl
http://www.runoffgroove.com/newclipper.html

Thanks

Pete

[theehman]

Doesn't sound like any blue Clipper I've seen.
That parts count is more consistent with the Orange Squeezer, but yours has BJTs, not FETs.

[geezer15]

Tha'ts interesting. Thanks for your prompt reply.

Here's a photo (I hope).

http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=IMG_1946crop.jpg

[geezer15]

Just noticed it also has a component missing above the two electrolytic caps.

[geezer15]

This is my best guess at the schematic.

http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=blueclippergrahamclark.jpg

There is a missing component, I think, is an electrolytic cap as the board has a + symbol similar to the other electrolytic caps on the board. I have no idea what the diode type is it has no markings. R10 ends at a silver pad on the board and does not connect to anything else. R3 ends at a terminal which must have once had a wire attached. If you look at the photo of the board there is a yellow wire which links to another space where a wire must have been but does not link to any component on the board.

Any assistance appreciated. I want to add the missing cap and wire it up to a battery and try it out.

Thanks

Pete

[theehman]

Makes me wonder if it's not really a WD Music Blue Clipper.  I'd read somewhere that they weren't exactly the same as the originals.

[geezer15]

This is a better version of the schematic!

[geezer15]

Oops would help if I added the link!


http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=blueclippergrahamclarke_0001_NEW.jpg

[geezer15]

The owner is sure this is a Dan Armstrong Blue Clipper. He remembers where and when he bought it, how much for and why he removed it from its original case etc. I have to agree it looks much more like an orange juice squeezer but then again all the component values are way different and its far from the same layout. So I have not idea what it is.

I decided to try it out. First I added the input and output jacks where I thought they might go and I got a signal to the IC pin 2 and out of pin 6. I then added a battery +ve to pin 7 and -ve to the earth jack pin (also goes to pin 4) as soon as i do this I get no input signal any where. Actually it is fine with just the +ve battery terminal connected but the sound disappears when I add the -ve battery terminal.  I also added a capacitor to the empty holes on the board. I guessed the missing component was a 10uF  electrolytic capacitor due to the + symbol on the reverse on the board next to one of the vacant holes. I just guessed a value based on the other two capacitors. Still nothing. Not sure what else to try now.

http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=IMG_1952e.jpg

http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=IMG_1949e.jpg

[theehman]

Pretty strange circuit.

[analogguru]

The owner is sure this is a Dan Armstrong Blue Clipper. He remembers where and when he bought it, how much for and why he removed it from its original case etc.

1.) The owner must have a lack of memory or is a liar.
2.) The chip dates to October 1983.
3.) The green resistors are Philips Metal-film resistors which have not been in use in the 70´s
4.) The yellow 47n capacitors also haven´t been inuse in the 70´s
5.) Therefore the owner cannot have bought it in 1976

6.) On the track side of the pcb is written "C-Tape" and "NB1"
7.) C-Tape (Developments Ltd) was a british company from Hampshire who produced the C-Ducer Microphones in the 80´s

8.) Here is the schematic of your C-Tape NB1 preamplifier.  For the missing cap you can use 1µF.



analogguru

[geezer15]

That's brilliant thank you! I had googled C-Tape and NB1 but didn't get any useful responses.

I spoke to the owner last night. He certainly isn't a liar and has no reason to but we can all make mistakes and be forgetful! (says he's never owner an orange juice squeezer lol) I will ask him about this pre amp next time I see him though. He was fairly sure there are no missing components as it has been kept in a box and nothing was in the bottom of it when he took it out but there you are.

Armed with your new info I will try again to get it working.

Thanks again for your input and effort.

Pete

[analogguru]

That's brilliant thank you! I had googled C-Tape and NB1 but didn't get any useful responses.

You can show the owner a typical C-ducer system here:
http://www.c-ducer.com/row/row_cpm_3.htm

Armed with your new info I will try again to get it working.

In doing so, keep in mind, that this preamp was designed for high-impedance piezo pickups and that you can´t connect it to a guitar (or other low impedance dc-signal source) without adding a coupling capacitor (~ 100n) at the input.

analogguru

[geezer15]

yes Thank you again. I wondered why there was no capacitor at the input.

Now I assume, from your diagram, the glass  fuse looking component on the top right hand side is actually a capacitor and not a diode as I had guessed. It certainly doesn't look like either that I've seen before.

Pete

[analogguru]

Yes, it is a polystyrene capacitor:
http://www.hificollective.co.uk/components/polystyrene.html

If you can read a value, please let me know and I will add it to the schematic.

analogguru

[geezer15]

Sorry there is no value on it- just a plain metal band round the glass tube.

[geezer15]

Confession from owner-
Yes he did own a c-ducer. As soon as I started giving him the info, the penny dropped. He has cared for this board thinking it was the blue clipper. He is now turning his house upside down looking for the correct circuit.

In the meantime I have ordered some parts and am going to try and make this pedal, housing it as a floor pedal with a volume control.

1) I found a gut shot and schematic showing an RC 4558 not a TL071 - I will socket and see. I have a TL072 I was going to use but the pin out is obviously different, as its a dual version of the 71, so I have ordered a 71 so i can easily swop it with the 4558.

2) The two biasing resistors seem to be 200k and 240k (from the photo)  not 20k and 240k or both 22k as I have seen on different schematics.

2) The two 4.7uF caps look like tantalum (I have electrolytic caps of the correct value but have ordered the tants. for authenticity/comparison).

3) had trouble tracking a 33nF capacitor and  1N914 diodes, neither stocked by my usual suppliers  but found some on e-bay. (had some 1N4148's on standby again I will compare them).

Thanks for your help and comments.

Pete

[Mike Burgundy]

FYI - 4558 is a dual, same pinout as a TL072.
TL081 and 071 (single opamps, both identical pinouts)are interchangeable ( I think the 71 has slighly less noise, but I may be wrong, didn't bother to look at a datasheet)

[geezer15]

Thanks Mike re double op amp.

I have built the circuit as the perfboard layout but put 200k and 240k resistors in place of the two 22k in the  voltage divider as per original and altered the IC pin outs for the dual op amps (using a TL 072 at the moment). ie +9v from pin 7 to pin 8,  output from 6 to pin 1. pin 2 ,3 and 4 remain the same. I used a 10k pot for the volume and added an on off foot switch. Got some 1N914's and 33nF cap, used tantalum's for the 4.7uF caps

It sounds great when its on. The only issue I have is that the signal dies when the pedal is turned off. The volume pot  works as well ie I can hear a signal when the pedal is off and at full volume but its way too loud when I switch it on, when I turn it down there is no audio signal when I turn it off. It is also noisy and sucks tone.

I wired the switch so the signal goes direct to the out jack when its off. Meter says this is ok. ie in and out jacks are connected together when its off. When its ' on' the signal goes to the perfboard and the 'out' from the perfboard goes to the volume pot and then to the out jack on the same lug as the direct signal. The other jack lugs both go to ground as does the 3rd lug on the vol. pot.

Oh well it works, shame I still don't have the original to compare it with.

[geezer15]

Sorted it!. Schoolboy error on the switch wiring. Rushing I guess.