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Maestro Boomerang Pot Replacement
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adam79
Jul 27, 2012, 10:11:07 AM7/27/12
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I have a Maestro Boomerang BG-2 that needs a replacement pot. The only
25k 5 watt pot (stock specs) is a linear taper; I need an audio or S
taper. The pot in these pedals is infamous for failing, and also for
being nearly impossible to replace. Has anyone had any luck finding a
replacement pot that works?
Thanks,
-Adam
25k 5 watt pot (stock specs) is a linear taper; I need an audio or S
taper. The pot in these pedals is infamous for failing, and also for
being nearly impossible to replace. Has anyone had any luck finding a
replacement pot that works?
Thanks,
-Adam
boardj...@gmail.com
Jul 27, 2012, 9:48:00 PM7/27/12
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boardj...@gmail.com
Jul 27, 2012, 9:50:18 PM7/27/12
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On Friday, July 27, 2012 10:11:07 AM UTC-4, adam79 wrote:
On Friday, July 27, 2012 10:11:07 AM UTC-4, adam79 wrote:
Dave M.
Jul 28, 2012, 9:10:40 AM7/28/12
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Adam,
You can find the schematic here.
http://www.experimentalistsanonymous.com/diy/Schematics/Filters%20Wahs%20and%20VCFs/Maestro%20Boomerang%202.pdf
Like boardjunkie I see no reason for a 5 watt pot. That's just a 9 v
circuit. Any wattage should do. Find a pot that's fairly rugged, has similar
dimensions to the one you are replacing and the same number of rotations
(probably 1). Mouser has lots of these.
Dave M.
You can find the schematic here.
http://www.experimentalistsanonymous.com/diy/Schematics/Filters%20Wahs%20and%20VCFs/Maestro%20Boomerang%202.pdf
Like boardjunkie I see no reason for a 5 watt pot. That's just a 9 v
circuit. Any wattage should do. Find a pot that's fairly rugged, has similar
dimensions to the one you are replacing and the same number of rotations
(probably 1). Mouser has lots of these.
Dave M.
joeg...@gmail.com
Jul 28, 2012, 11:00:05 PM7/28/12
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adam79
Jul 29, 2012, 5:41:45 PM7/29/12
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On 7/27/12 9:48 PM, boardj...@gmail.com wrote:
>
> 5 watt pot? I don't think so. Its .5w (half watt). Find a 25k audio taper in an old mixer that's be'n robbed for parts. The old style CTS quarter sized pots will hold up better. You'll have a hard time findin' a mil spec "sealed" 25k in audio taper.
>
Huh. When first researching the pot problem I found a website that has
>
> 5 watt pot? I don't think so. Its .5w (half watt). Find a 25k audio taper in an old mixer that's be'n robbed for parts. The old style CTS quarter sized pots will hold up better. You'll have a hard time findin' a mil spec "sealed" 25k in audio taper.
>
some info on the topic.. cleaning the orig pot, replacing it, etc. I've
been emailing with him and he told me it was a 5 watt pot.
I've been looking everywhere it's really hard to find a 25k pot w/ a S
or audio taper.. they're all linear. I know it doesn't meet the specs,
but I wanted to try something, so I went and bought this pot on eBay:
http://r.ebay.com/1PTWHi. Hopefully it'll work.
adam79
Jul 29, 2012, 9:55:07 PM7/29/12
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Apparently in his experience with the BG-2, a 5 watt pot will last longer.
boardj...@gmail.com
Jul 29, 2012, 11:40:30 PM7/29/12
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On Sunday, July 29, 2012 9:55:07 PM UTC-4, adam79 wrote:
> Apparently in his experience with the BG-2, a 5 watt pot will last longer.
>
Utter horseshit. The pot is part of an audio filter....there's no current there to speak of. What makes a pot last longer in this application is build quality. The 2w pots used in some wah pedals aren't used because of the wattage rating, but because of mechanical reliability.
> Apparently in his experience with the BG-2, a 5 watt pot will last longer.
>
Flasherly
Jul 30, 2012, 12:06:37 AM7/30/12
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On Jul 29, 5:41 pm, adam79 <ada...@toast.net> wrote:
Measure the resistance across the legs and buy both linear and audio
to try;- or pickup a ganged two stage pull/push, and maybe modify it
for either (if enough room behind the faceplate). There's some really
high-end stuff out there for fail-safe type operation especially in
geetars, or, as always, both good quality, regarded electronics brand
parts if not snake oil.
to try;- or pickup a ganged two stage pull/push, and maybe modify it
for either (if enough room behind the faceplate). There's some really
high-end stuff out there for fail-safe type operation especially in
geetars, or, as always, both good quality, regarded electronics brand
parts if not snake oil.
Lord Valve
Jul 30, 2012, 11:39:43 AM7/30/12
to
Bears manuf/date code of 1378139, part #925-010694.
1" long slighty flatted shaft, 3/8" bushing 1/2" long, solder
terminals stick straight out. Make me a disgustingly huge
offer I can't refuse.
Lord Valve
Expert (eat me)
303-778-1156
Lord Valve
Jul 30, 2012, 12:09:18 PM7/30/12
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SAE (3/8") bushing 9/32" long...but the 1/4" shaft is only
11/32" long. Could be rigged - maybe. These are cheap.
Of course, they're only specked for normal audio use, so
the rotational life may not be sufficient. Alpha may well
offer this with a longer shaft, but no distributor I'm aware
of carries it.
Lord Valve
Expert (fuck you)
adam79
Jul 30, 2012, 11:29:37 PM7/30/12
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Is it a Centralab?
adam79
Jul 30, 2012, 11:33:37 PM7/30/12
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I found this pot on eBay: http://r.ebay.com/kOQOGo. It's a PCB mount,
but they an be adjusted for soldering.
but they an be adjusted for soldering.
Joe Gagan
Jul 31, 2012, 10:17:36 AM7/31/12
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the pot you linked to above has a 3/16ths shaft, the gear will not fit that shaft without a bushing.
the original centralab taper ( and the CTS of the BG1 that preceded it) is a non-standard taper. audio taper is not correct. it will provide an accent in the high-mids as opposed to the low-mids accent of a classic BG2. also, 25k will not give full treble, the stock centralabs i have analyzed are all within 3% of 30k.
the original centralab taper ( and the CTS of the BG1 that preceded it) is a non-standard taper. audio taper is not correct. it will provide an accent in the high-mids as opposed to the low-mids accent of a classic BG2. also, 25k will not give full treble, the stock centralabs i have analyzed are all within 3% of 30k.
Lord Valve
Jul 31, 2012, 11:04:17 AM7/31/12
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Do you understand what "NOS" and "OEM" mean?
Do you know how to read maufacturer and date codes?
Probably not. OK, in English - what I have are the
*ORIGINAL* BOOMERANG POTS, obtained as shop
spares stock over thirty years ago. They are absolute
fucking unobtainium - if there are three people on this
planet who have any of these besides me, I'll be
flabbergasted.
Clear?
Lord Valve
Expert (like it or not - and y'all know who you are, right?)
adam79
Jul 31, 2012, 11:40:17 PM7/31/12
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How much do you want for one? Or two if the price is right..
Thanks,
-Adam
Thanks,
-Adam
adam79
Aug 1, 2012, 2:22:28 AM8/1/12
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It's a S taper, right?
boardj...@gmail.com
Aug 1, 2012, 2:04:19 PM8/1/12
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On Wednesday, August 1, 2012 2:22:28 AM UTC-4, adam79 wrote:
> It's a S taper, right?
>
S taper schmess taper. Its the *right* part....
> It's a S taper, right?
>
adam79
Aug 1, 2012, 6:17:40 PM8/1/12
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I'm not questioning you, or the part. I'm just curious about the pot's
taper.
taper.
adam79
Aug 2, 2012, 2:51:33 PM8/2/12
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Maestro must have had a surplus of CTS pots left over from the BG-1;
I've seen BG-2's with those CTS pots.. I'd guess that they were used on
the first production run of the BG-2 until they ran out. I also read
somewhere that the original Boomerang is the benchmark for all other
versions.
If all the pots are within 3% of 30k, why does the schematic have it
listed as 25k? As far as the 3/16ths shaft goes, are you saying that the
screw that holds the gear in place isn't long enough to secure itself on
the shaft?
Also, if Lord Valve is reading this, I'm still interested in one or two
of the OEM pots you have. Just waiting on a price quote.
Thanks,
-Adam
On 7/31/12 10:17 AM, Joe Gagan wrote:
I've seen BG-2's with those CTS pots.. I'd guess that they were used on
the first production run of the BG-2 until they ran out. I also read
somewhere that the original Boomerang is the benchmark for all other
versions.
If all the pots are within 3% of 30k, why does the schematic have it
listed as 25k? As far as the 3/16ths shaft goes, are you saying that the
screw that holds the gear in place isn't long enough to secure itself on
the shaft?
Also, if Lord Valve is reading this, I'm still interested in one or two
of the OEM pots you have. Just waiting on a price quote.
Thanks,
-Adam
On 7/31/12 10:17 AM, Joe Gagan wrote:
Lord Valve
Aug 2, 2012, 2:55:18 PM8/2/12
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Cats who knew what I had have bought all I'm willing to part with.
Joe Gagan
Aug 2, 2012, 11:54:48 PM8/2/12
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there were never CTS pots used in production BG2s, according to richard mintz. his company built every single BG2. please, can you link to the photos of original BG2s that have CTS pots?
replacement parts are another story altogether, i have no info about this, except to say that i once serviced a 72 boomerang that had a correct centralab part with a '77 date code. i assume that someone had the 72 serviced by an authorized dealer who had access to the correct part.
why do they measure 30K? i don't know. but at least 10 originals fall into this pattern.
a 3/16ths diameter shaft will require some sort of rigging so that the 1/4" hole on the round gear will work.
i offered you a very fair price to provide you with a working, durable pot specially prepared to work in a boomerang, you said my price was too high.
i have a special testing rig and have collected data on at least a hundred pots for wah. who pays me for this research? i certainly don't make it up on a 6 dollar markup on a pot. all this, assuming my labor is 2.00 per hour for the prep work and mailing, not including the emails and paypal crap.
you will run into myriad problems trying to get an average log pot to work in a boomer. first off, it is a modified rev log. even harder to find than log.
second, the average taper will have insufficient travel at the treble end to allow the footswitch to engage without either damaging the pot or jumping a tooth, or both. the alternative is to leave it at less than full treble. which a 25k pot will not give you anyway ( problem #3)
4. bushing, shaft length all have to be long enough to work, or you have to find workarounds for those issues as well. 5. durability issues. 6. many pots, including the centralab originals sometimes have a defect in the trace, which causes a terrible static at the end of rotation. there are a few tricks to remedy this, but sometimes the pot simply has to have a compromised high end to avoid the noise. r mintz said that a large number of the original pots were unusable due to this defect.
another finding: the common trick of using a 100k wah pot with a 33k limiting resistor compromises the sound and foot feel. i have serviced many BG2s that came to me with this 'fix'. the limiting resistor exacerbates the kink in the sweep- it compresses it even further. you completely lose the expressive extended mid emphasis and sweet spot that boomers are famous for. there is more to this, but that is the cliff notes version.
sounds like you are doing your own research, this will be a fun experience, i am sure.
replacement parts are another story altogether, i have no info about this, except to say that i once serviced a 72 boomerang that had a correct centralab part with a '77 date code. i assume that someone had the 72 serviced by an authorized dealer who had access to the correct part.
why do they measure 30K? i don't know. but at least 10 originals fall into this pattern.
a 3/16ths diameter shaft will require some sort of rigging so that the 1/4" hole on the round gear will work.
i offered you a very fair price to provide you with a working, durable pot specially prepared to work in a boomerang, you said my price was too high.
i have a special testing rig and have collected data on at least a hundred pots for wah. who pays me for this research? i certainly don't make it up on a 6 dollar markup on a pot. all this, assuming my labor is 2.00 per hour for the prep work and mailing, not including the emails and paypal crap.
you will run into myriad problems trying to get an average log pot to work in a boomer. first off, it is a modified rev log. even harder to find than log.
second, the average taper will have insufficient travel at the treble end to allow the footswitch to engage without either damaging the pot or jumping a tooth, or both. the alternative is to leave it at less than full treble. which a 25k pot will not give you anyway ( problem #3)
4. bushing, shaft length all have to be long enough to work, or you have to find workarounds for those issues as well. 5. durability issues. 6. many pots, including the centralab originals sometimes have a defect in the trace, which causes a terrible static at the end of rotation. there are a few tricks to remedy this, but sometimes the pot simply has to have a compromised high end to avoid the noise. r mintz said that a large number of the original pots were unusable due to this defect.
another finding: the common trick of using a 100k wah pot with a 33k limiting resistor compromises the sound and foot feel. i have serviced many BG2s that came to me with this 'fix'. the limiting resistor exacerbates the kink in the sweep- it compresses it even further. you completely lose the expressive extended mid emphasis and sweet spot that boomers are famous for. there is more to this, but that is the cliff notes version.
sounds like you are doing your own research, this will be a fun experience, i am sure.
Joe Gagan
Aug 2, 2012, 11:59:18 PM8/2/12
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adam79
Aug 3, 2012, 4:56:17 PM8/3/12
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On 8/2/12 11:54 PM, Joe Gagan wrote:
>
> i offered you a very fair price to provide you with a working, durable pot specially prepared to work in a boomerang, you said my price was too high.
oh, that was you that sent that email? i got it confused with someone
>
> i offered you a very fair price to provide you with a working, durable pot specially prepared to work in a boomerang, you said my price was too high.
else that was trying to rip me off from craigslist..
adam79
Aug 8, 2012, 10:08:04 PM8/8/12
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I sent you an email w/ my PayPal info. Send me an invoice if you'd be so
kind. Thanks.
kind. Thanks.
groo...@gmail.com
Nov 28, 2014, 9:44:30 AM11/28/14
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Jeannie B
Mar 22, 2022, 4:45:39 PM3/22/22
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