Boss GE-7 Mods

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
Post Reply
User avatar
marmaliser
Breadboard Brother
Information
Posts: 135
Joined: 21 Jun 2010, 18:14
Has thanked: 52 times
Been thanked: 42 times

Post by marmaliser »

Just replace the ones marked TL022

User avatar
andyg_prs
Information
Posts: 8
Joined: 24 May 2011, 09:22

Post by andyg_prs »

Hi,

I'm confused as to which op amps need to be replaced in the old 4 op amp version....sorry to be a pain but want to make sure I buy the correct parts!

Cheers,
Andy

roseblood11 wrote:The opamps are the most important part. Then you could replace all electrolytic caps in the audiosignal path with film caps (Panasonic SMF are small enough). If there are carbon resistors with higher values, replace them with metalfilm
and from a previous post:

by roseblood11 » 17 Jan 2009, 02:42
Hi,

-replace the three JRC022D with RC4559P
(NE5532AP, OPA 2134, OPA2132 or OPA2604 should work as well and maybe even sound better, but the 4559 is a good and cheap choice here - it´s most important to replace the NJM2068 with a high quality, low noise chip, see below...)

-replace capacitors:
C18,C25, C29, C30 : 0.047 µF
C21, C22, C32 : 1 µF
C13 : 0.1 µF
(use stacked metal film caps (MKT) for all positions!!! Panasonic ECQ-V series sounds very good here)

-Replace NJM2068 at position IC3 with a OPA2134 (use a DIP-SIL-Adapter or built an adapter using perfboard). (Look at the photo below)
DIP-SIL-adapter: http://www.musikding.de/product_info.ph ... --SIL.html (you can buy them from Monte Allums, I guess)

User avatar
marmaliser
Breadboard Brother
Information
Posts: 135
Joined: 21 Jun 2010, 18:14
Has thanked: 52 times
Been thanked: 42 times

Post by marmaliser »

Here is the guide I used. http://www.rhythmanddetonation.com/?p=79 with a nice big piccie of the PCB

Pretty sure the Vintage version has 3 TL022 which are crap and can be replaced with TL072 , 4559P , NE5532AP etc . Think I used 4559's IRC. The NE is supposed to be good but is quite High current

The 4558DD (the IC by itself) does not need changing

User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

Replace everything that looks like "...022" or "4558" with 4859.

Is the a HA12017 or similar? I guess that it´s a standard dual opamp in a SIL package, but I´m not sure, if it has the same (standard) pinout as the mentioned NJM2068 opamp, so you have to compare datasheets to see how the DIP-SIL adapter for the OPA2134 has to be wired. (That´s the most important part, as it´s the first opamp in the signal chain...)

User avatar
andyg_prs
Information
Posts: 8
Joined: 24 May 2011, 09:22

Post by andyg_prs »

Cool, thanks - and how good was the result? did you put the op amps straight in or fit a socket?
marmaliser wrote:Here is the guide I used. http://www.rhythmanddetonation.com/?p=79 with a nice big piccie of the PCB

Pretty sure the Vintage version has 3 TL022 which are crap and can be replaced with TL072 , 4559P , NE5532AP etc . Think I used 4559's IRC. The NE is supposed to be good but is quite High current

The 4558DD (the IC by itself) does not need changing

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Could anyone help me with a BOSS GE7 mod I did?

You better watch it:

It´s not the perfect video, I know !..

Many thanks !

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

Did you change R1 from 470 ohm to 47-100 ohms? This is necessary when using op amps which draw more current, like the 4559s and OPA2134. Check the DC voltage at pin 8 of the 4559s and OPA2134....if it is 7vDC or less, too much voltage is being lost through R1 and D1.

I prefer to power my modified GE7s with a regulated 12vDC supply - the OPA2134 definitely performs better at 12v than 9v.

User avatar
OrionManMatt
Breadboard Brother
Information
Posts: 90
Joined: 23 Dec 2007, 19:37
my favorite amplifier: AC30
Completed builds: BB Preamp, volume pedals, tap tempo boxes, etc.
Location: Texas
Has thanked: 3 times
Been thanked: 16 times

Post by OrionManMatt »

blackbunny wrote:Did you change R1 from 470 ohm to 47-100 ohms? This is necessary when using op amps which draw more current, like the 4559s and OPA2134. Check the DC voltage at pin 8 of the 4559s and OPA2134....if it is 7vDC or less, too much voltage is being lost through R1 and D1.

I prefer to power my modified GE7s with a regulated 12vDC supply - the OPA2134 definitely performs better at 12v than 9v.
Will the GE7 accept that voltage without further modification? I was thinking of modding my older model with either OPA2134 or RC4559Ps. I've got a PP2 that would supply it if so.

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

Mine have all been powered by regulated 12vDC supplies for over 10 years with no problems. I have 2 old Japanese-made ones and 3 Taiwanese-made ones with the newer PCB layout.
After a bit of trial and error, I found that supply voltages from around 10.5vDC and up noticeably improve the performance of the high-performance op-amps.

I settled on 12vDC as it is readily available, and you don't have to upgrade the capacitors in most pedals as they are 16vDC rated. It pays to look at the schematic diagram and PCB components of your pedal to be sure, especially if it contains digital or logic ICs. Most decent digital delays and modelling amps have voltage regulators for the CPU on the PCB anyway.

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Hello again.
Another member of freestompboxes.org asked me some questions about my GE7:
1- What version of the GE-7 do you have?
2- Does it work with a battery?
3- What kind of power supply do you use?
4- Is the Ge-7 made for the old Boss ACA power adapter?
Those pedals have an internal power stabilization, because the adapter hasn´t got one. If you use them with a modern adapter, which has a stabilization, they might not work, because there isn´t enough voltage left for the circuit. If you run another pedal sharing the power supply, the internal stabilization of those old pedals is bridged, and they will work.
But I thought that all Ge-7s were made for the modern stabilized PSA-power adapter?!?
1- The BOSS GE7 I have is a TAIWAN, the "New" 3-opamp GE-7 version, like this
-----------------------------------------------------------------------------------
2- When using it with a 9v battery this are the facts:
a- It makes BIG NOISE.
b- When I press the switch the noise "almost" dissapear and the guitar signal sounds.
c- The switch doesn't work as should: it works as a MOMENTARY SWITCH, when I stop pressing it with the finger, the BIG NOISE starts again.
------------------------------------------------------------------------------------
3- The power supply I use is a BOSS PSA230S, plugged to this cord
------------------------------------------------------------------------------------
4- I don't know if this model was made for the old Boss ACA power adapter, but I have many other different Boss pedals, from 80's till 2010 and I haven't had any problem with power supplies.

bye !
Last edited by mortad on 15 Jun 2011, 13:39, edited 2 times in total.

User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

blackbunny wrote: Most decent digital delays and modelling amps have voltage regulators for the CPU on the PCB anyway.
...that might get hotter if they see a higher input voltage.

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

mortad wrote:3- The power supply I use is a BOSS PSA230S, plugged to this cord
------------------------------------------------------------------------------------
4- I don't know if this model was made for the old Boss ACA power adapter, but I have many other different Boss pedals, from 80's till 2010 and I haven't had any problem with power supplies
The point here is that the replacement high performance IC's draw much higher current than the originals, resulting in poor performance when using a battery, and a large voltage drop across R1 and D1 due to the high current draw.

I didn't mean to create confusion about the different Boss power supplies used in early Boss pedals and later Taiwanese ones. I only use 12vDC regulated supplies for my Boss pedals that have been upgraded with high performance, higher current op amps. This does not refer to stock Boss pedals,which use op amps chosen for longer battery life, rather than low noise or good audio quality.

When you upgrade a pedal with higher slew rate, low noise, high current draw op amps, it may not work on a 9v battery or a 9vDC supply without other circuit modifications!

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

roseblood11 wrote: ...that might get hotter if they see a higher input voltage.
True....hence my caveat about looking at the PCB components and schematic to identify any components that might be at risk.
Remember, we are talking here about modifications to increase performance in effects pedals originally designed to use 9v batteries as a power source.

FWIW, I have 2 Taiwanese-made Boss DD-3 pedals that have been running perfectly since 1992 on regulated 12vDC supplies. The extra supply voltage hasn't bothered the on-board 5v regulator that feeds the CPU.

Boss pedal owners should note that many Boss pedals have an 11 volt zener diode in the DC supply line as protection against over-voltage. I recommend leaving these IN if the pedal is stock, but they can be replaced with a 12v, 13v or 15v zener in most models to obtain higher voltage for boo-teek op amps.....only after careful checking of the circuit and components.

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Hi again and thanks for your information !

I've done this Mod thinking that it would work on standard 9v, (the GE7 alone or with more pedals sharing DC).

So now, next question:
1- Is this Mod focused on runnig the GE7 ONLY with 12v or there is posibility about choosing 9 or 12v?
2- In the case that I want to run my modded GE7 with 9v, Which OTHER components should I change, and which values should the replacements have for running it without problems with 9 v?
Blackbunny said about R1 from 470 ohm to 47-100 ohms... What about D1?... Any more components?

Well, I aprecciate your help and knowledge, so interesting! :thumbsup
Many thanks

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

mortad wrote:1- Is this Mod focused on runnig the GE7 ONLY with 12v or there is posibility about choosing 9 or 12v?
You can still use 9vDC, if you reduce the voltage drop across R1 and D1. Use a 47 ohm 1/4 watt resistor for R1, and try and get a Schottky diode for D1, such as a 1N60P or a 1N5817/5818/5819.
You can also simply solder a link across D1, but the circuit won't have as much protection from accidental reverse-polarity of supply voltage.
mortad wrote:2- In the case that I want to run my modded GE7 with 9v, Which OTHER components should I change, and which values should the replacements have for running it without problems with 9 v?
The power supply modification outlined above should be all that is necessary to run the pedal from a 9vDC power supply.
The pedal (modified with high performance op amps) may draw too much current to work from a 9v battery though.

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Hi !
I just changed the R1 for a 47 ohm 1/4 watt resistor and D1 for a Schottky diode 1N5819.

The problem continues, exactly the same plus now the LEd doesn't light up. :shock:

ups ! :(

User avatar
blackbunny
Resistor Ronker
Information
Posts: 372
Joined: 07 Jan 2011, 07:41
my favorite amplifier: Fender Blackface
Completed builds: Lots of mods to lots of pedals
Location: the garage
Has thanked: 270 times
Been thanked: 108 times

Post by blackbunny »

With a plug in the input jack and the power supply connected and powered on, check the DC voltage between pin 4 and pin 8 of each op amp. Pin 8 should be around +8.5v with pin 4 = 0. Then check pin 6 of the HA12017 and pin 3 of the other op amps for 1/2 supply voltage, or around 4.3v. If you don't get close to these readings, check the DC voltage drop over R1, and then D1.

Check your solder joints to make sure that you haven't bridged any tracks.

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Hi !
I just received this info from Roland Europe, the electronic schematic for GE7(1), GE7(2) and GE7B (bass).
GE7(1)
GE7(2)
GE7 Bass

Hope it could help anyone. :thumbsup
See ya !

User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

Thanx!

But do you have larger files? The parts values are almost not readable. Esp the Ge-7 for guitar, second version, would be interesting

User avatar
mortad
Information
Posts: 15
Joined: 01 Nov 2010, 16:43
Been thanked: 1 time

Post by mortad »

Hi !
These are the original pdf files that I received from Roland Central Europe.
http://www.megaupload.com/?d=GIPYB5XS

The contact is:
URL: http://www.rolandce.com
E-MAIL: fabio.picchi@rolandce.com

byee !

Post Reply