[stripboard] Maestro BG-1 Boomerang

sinner · Post by **sinner** » 16 Jun 2012, 19:19

Factory schemo shows P-2336 transistors for Q1 and Q2 - good luck searching

Pinout shown is for BC108B or similar.

Inductor is spaced for typical, common "halo" type. Originally it is indeed 500mH, but about 40R resistance, so no quite "halo" spec... just saying...

Pot taper is also odd - 25k is not easy score

beedotman · Post by **beedotman** » 18 Jun 2012, 13:57

Sinner, input resistor should be 47K in place of "standard" 68K value, right?
I'm refering to this schematic:

sinner · Post by **sinner** » 18 Jun 2012, 13:59

I was working with factory schemo attached to the back plate of it. I have detailed picts from Joe Gagan who owns it, I'll check it against errors

sinner · Post by **sinner** » 18 Jun 2012, 14:00

As you see there is more differences, like resistor value at collector to base in second gain stage

sinner · Post by **sinner** » 18 Jun 2012, 14:07

here's the pictures I was referring to http://www.turretboard.org/?p=504

beedotman · Post by **beedotman** » 18 Jun 2012, 14:21

sinner wrote:As you see there is more differences, like resistor value at collector to base in second gain stage

yup! this resistor is to simulate transistor leakage, right?

sinner wrote:here's the pictures I was referring to http://www.turretboard.org/?p=504

cool. thx.

beedotman · Post by **beedotman** » 18 Jun 2012, 14:25

sinner wrote:Inductor is spaced for typical, common "halo" type. Originally it is indeed 500mH, but about 40R resistance, so no quite "halo" spec... just saying...

Arteffect SOD has nominal inductance 550mh and nominal Resistance 42.5Ohms, so could be more or less close

According to SBE description

http://www.smallbearelec.com/servlet/Detail?no=1132

sinner · Post by **sinner** » 18 Jun 2012, 14:30

beedotman wrote:
sinner wrote:Inductor is spaced for typical, common "halo" type. Originally it is indeed 500mH, but about 40R resistance, so no quite "halo" spec... just saying...
Arteffect SOD has nominal inductance 550mh and nominal Resistance 42.5Ohms, so could be more or less close
According to SBE description
http://www.smallbearelec.com/servlet/Detail?no=1132

Good to know

SOD is spaced differently. it takes .15" pitch vero better, I'll do one for it

beedotman · Post by **beedotman** » 18 Jun 2012, 14:34

sinner wrote:SOD is spaced differently. it takes .15" pitch vero better, I'll do one for it

hehe. cool!

prehistoric · Post by **prehistoric** » 06 Jul 2012, 21:50

very nice project here, i just found it!

even though the factory schem lists the base Q1 R as 4.7k, i recently noticed our unit has 1.5k, just like the BG2. so the only differences in tone between the BG1 and BG2 would be due to the extra components to make the BG2 a volume pedal in 'off' mode.
i have tried the arteffect inductor (SOD, 550Mh ), it sounds great in a standard BG2.arteffect used to offer the SOD in both 500 and 550 Mh, not sure if they are even still making them.

guitar_slinger · Post by **guitar_slinger** » 28 Dec 2012, 05:05

sinner wrote:Factory schemo shows P-2336 transistors for Q1 and Q2 - good luck searching Pinout shown is for BC108B or similar.

Inductor is spaced for typical, common "halo" type. Originally it is indeed 500mH, but about 40R resistance, so no quite "halo" spec... just saying...

Pot taper is also odd - 25k is not easy score

sorry about the question, as for the pin outs underneath the inductor are the black dots connections and red ones cuts?

Max Cohen · Post by **Max Cohen** » 29 Dec 2012, 05:58

Red dots are the hot inductor lugs. Black dots are supportive whipple lugs. They dont need to be cut off or brake the vero. They have no connection to anything

atreidesheir · Post by **atreidesheir** » 31 Dec 2012, 06:02

Pawel, did you ever wind some inductors.
If you did, was it worth the effort?

I used one of these little transformers (from Smallbear) as an inductor with nice results on a Vox wah repair recently. I had one in the bin and it sounded correct.
http://www.smallbearelec.com/servlet/Detail?no=599
Smallbear description reads:
"Transformer - Mouser 42TM013
PC Mount, 1K to 8 ohms. The primary makes a decent, cheap 500 mh. inductor for a Wah or a Wild Mouse."

There are probably other similar small value transformers all over the world waiting to wah.

Max Cohen · Post by **Max Cohen** » 31 Dec 2012, 22:06

No bro, never had enough of time to focus my ass on it. I still have the electric motors taken out of an old CD and DVD players, and a digital counter. I know where to score the shells, and wire, so me thinks it's just a question of time.

...but - I just changed my work, and the time is what I'm short with

atreidesheir · Post by **atreidesheir** » 31 Dec 2012, 23:54

I understand. There is plenty of time for everything but fun these days here too.

Professor SourTone · Post by **Professor SourTone** » 23 Sep 2016, 16:04

jtrezzo · Post by **jtrezzo** » 22 Nov 2016, 18:51

Does anyone have the stripboard layout still? It seems to no longer show up. I had this originally from Turretboard.org years ago but cannot find it anywhere now. This is all I have (thanks to Wayback Machine) but it's tiny and unreadable!

beedotman · Post by **beedotman** » 01 Dec 2016, 14:25

it took me a while but found it

jtrezzo · Post by **jtrezzo** » 28 Dec 2016, 06:22

I just made this. I used BC108s for the transistors and the Eleca Halo inductor with the Joe Gagan Boomerang pot. Sounds great!