I got a CS flanger but its in a sorry state, I would love to get it running but as they're pretty rare I cant find a schematic could anyone help?
I just got this Arbiter Booster, i had only seen one pic of it before, if there isnt a known schematic lurking around i'll trace it out when I get time ;)
(http://i23.ebayimg.com/03/i/08/10/c5/c4_12.JPG)
(http://i6.ebayimg.com/05/i/08/0e/1a/d3_12.JPG)
(http://i19.ebayimg.com/02/i/08/0a/b8/d6_12.JPG)
Wow, great pictures; thanks!
Is "plus" the volume control?
Fkin insane, man! I would love too see the schem, when you have finished the tracing... Hope you will be investigating that device soon!!!
Great! ;)
yes, i too would love to see a layout. ;D
Wow.....
I didn't even know this pedal
QuoteWow..... I didn't even know this pedal
Neither did I...
...i used to have one of those ! ;D
AC
Here's the back of the board showing where the componts are placed, im terrible at drawing schematics (always get lost and miss parts out) maybe someone could have a go.
(http://img.photobucket.com/albums/v707/leonhendrix/AB.jpg)
P1/2/3 = Plus
B1/2/3 = Bass
T1/2/3 = Treble
Transistors are BC109c
I forgot the + symbol showing the polarity for the elec caps (2.2 & 20uf), looking at the board the -ve for both caps are at the top.
surprised no one asked...
how's it sound!? Like a Rangemaster or....
cool 8)
I've checked this thread several times and would love to have more details on how the pedal sounds too! It looks like an easy build once the schem is sussed.
I guess we need to know the pot values!
Thanks Leon!
Mojo Bump! :icon_biggrin:
It's buildable with the info you've supplied. Any chance you know the value of the pots?
I tried a schematic, but I haven't tried a breadboard yet.
If you see any mistakes call them out and I'll fix.
(http://www.digitalmgi.net/guy/trebface.gif)
3/4 North, that's awesome!!! 8) 8) 8) Now we have another British classic! :icon_exclaim: I would use 100k lin pots...
I built one last night using the trace photo as a template to construct using the 4ms CBCB method. I used PN2222 transistors and guessed at 100k pots. No joy! I didn't get a peep out of it. I finished too late to do any trouble shooting beyond confirming that all the traces where in fact connected. I'll work on it some more tonight and report if anything changes.
Rick
Sometimes it's easier to spot wiring and schematic errors when something is shown the way you expect it. I know it is certainly easier to keep track of transistor pins.
I flipped the schem and labelling around "the right way" :icon_wink: and posted it.(http://img.photobucket.com/albums/v474/mhammer/TBFACE.png)
Should that 2.2uf cap after the Plus control really be oriented that way?
Quote from: Mark Hammer on September 15, 2006, 11:39:20 AM
Should that 2.2uf cap after the Plus control really be oriented that way?
I'd say yes, since the base of the following transistor would have a higher potential (due to the 4k7 voltage divider) than the wiper of the plus-pot where (at the complete eq) no voltage is applied.
Am I right?
Regards,
tomboy
Mark, I wanted to have it read left to right but the pots prevented me. When it's flipped the 1 lug is where you would expect to find the 3 lug. But maybe that doesn't matter, I haven't drawn many schems and don't know.
Quote from: 3/4 North on September 15, 2006, 01:10:34 PM
Mark, I wanted to have it read left to right but the pots prevented me. When it's flipped the 1 lug is where you would expect to find the 3 lug. But maybe that doesn't matter, I haven't drawn many schems and don't know.
No, you did a great job, and many thanks for it. It's my stupid anglo-literate brain that doesn't want to make the directional leap from right to left. A lot of folks are very accustomed to the EBC pinout and left-to-right schematics, and can imagine a perfboard wiring of transistors using that pinout quite easily when viewing it that way. Switch to a different pinout like ECB and that facility declines considerably. Now flip the damn drawing so its "backwards", and we probably couldn't even solder in a resistor properly, let alone a transistor or pot! :icon_lol:
According to the image it looks like the resistor from Vcc to the base of Q2 should be 47k not 4k7, no?
I'm gonna try and breadboard this tomorrow but I don't have any bc109 on hand, what would be good substitutes?
-Lenny
Quotewhat would be good substitutes?
BC547-549, BC550, BC337, 2N5088, 2N5089, BC237-239, BC182-184
Quote from: Moonface on September 15, 2006, 06:26:53 PM
BC547-549, BC550, BC337, 2N5088, 2N5089, BC237-239, BC182-184
Excellent, thanks!
-Lenny
good work ;D
The pots are worn but it looks like they are all 25kA
yeah and the 4k7 from Q2 base to 9v should be 47K
;D
Success! It works. I'd say the 47k resistor made the difference. It's a little noisy but that's probably because it's not boxed.
The bass control seems to operate mostly as a bass cut control but the treble actually adds high end. I got a sound pretty close to bypass with the bass maxed and the treble minimized.
There isn't a whole lot of boost and what's there is mostly in the top little bit of the pot (I used linear pots for all the controls so that's to be expected). This might be due to the PN2222's I used since their gain is a little on the low side but I bet using higher gain transistors won't make much difference. There doesn't seem to be much difference when using a 100k volume control over using a 25k. I'd say use whatever is convenient.
I wouldn't call this a must build but it's simple enough that it can be thrown together in a couple of hours and it's certainly a nice enough addition to the booster family of effects.
Great! I couldn't figure it out last night, glad you guys did.
I updated the schem, flipped it for the transistors, then flipped the middle to get the pots reading the correct way.
Nota Bene:
The circuit is an emitter follower driving a passive Baxendall tone stage, and the "plus" control is simply a volume control before the final boost.
Passive Baxendalls typically have 20db of loss in the flat position, and generally use audio taper pots for linear effect-per-rotation feel.
Active Baxendalls achieve the same thing by using the frequency selective stuff as feedback, and look similar, but use linear pots.
The Colorsound Overdriver is a similar setup, but uses two transistors in a feedback-pair arrangement before an active Baxendall tone section.
Sorry, I wasn't able to post this weekend after I breadboarded the circuit. I don't have much to add at this point, and can only agree with what Rick and R.G. wrote. There isn't a whole lot of boost. I used 2 2N5088s and didn't have 3 25k pots so I used a 25k for the bass control, a 50k for the treble control and a 100k for the plus control. It works fine this way but of course I have no comparison to the sound of 3 25k pots. Out of interest I bypassed the tone circuit and that did indeed restore a lot of gain, and it didn't sound bad either. Before I did that though I replaced the emitter resistor on q2 with a 1k pot and was able to tickle a little more gain from the circuit by adjusting that as well.
Quote from: RickL on September 15, 2006, 11:07:38 PM
I wouldn't call this a must build but it's simple enough that it can be thrown together in a couple of hours and it's certainly a nice enough addition to the booster family of effects.
+1 on that. Overall it's a very subtle boost effect, but with nice tonal possibilities.
I wonder though. With this much of a gain loss through the passive tone control, isn't it a bad idea to run the q2 at a fixed gain and just attenuate the signal to that transistor? Won't the noise generated by q2 remain constant regardless of the plus setting? I'm thinking in terms of signal-to-noise ratio here.
-Lenny