JohnH
Well-Known Member
I got one of these last week. I'd been thinking about it before, and this thread reminded me again:
http://www.marshallforum.com/threads/say-‘ello-to-the-5-finest-marshall-guv’nor-clones.93122/
It's a pretty looking thing!:
Curved silver finish, embossed Marshall logo, die-cast body and all the gold bling on the knobs.
It's well built and solid, and you get a lot for not much $, including 4-way Eq, a circuit with four opamp stages and true bypass switching.
Testing it out, there's a huge range of tones and it seems to run from clean up to medium-high gain. But for all that, my first impression was it lacks some clear direct-sounding sparkle.
When I get a drive pedal, a lot of the fun for me, apart from playing it, is in working out how it works and how to adjust it to suit what I like.
Although it's quite well known, there is not as much online about it compared to other classic pedals such as TS's and SD-1's. This is the most common diagram online for the GV-2:
It has some suggestions from whoever marked it up. I checked against my pedal, and the component numbers seem to match. It also identifies how the pots and jack inputs are on their own boards. But it's a little hard to follow, a bit blurry and also wires cross that are sometimes joined and sometimes not.
So since other versions are hard to find, it's also a good idea to reference the original version of the Guv'nor, on which the GV-2 was based:
Neither of these are official versions, but all other schematics that I could find online are based on one or other of them.
Circuit Design
Both versions start similarly, with two non-distorting op-amp gain stages, which each include a capacitor in the feedback so bass is de-emphasised at higher gain - good practice in these circuits.
Then the distortion, with hard-clipping to ground using a pair of inverted red LED's. Mods on these components are one of the popular changes. Actually, the quality of tones that the LEDs create seem quite nice to me.
Then comes the passive tone stack, T, M, B, similar to a Marshall amp. At this point, the two versions vary because the original sends a signal out via a volume pot directly after the passive tone stack, with no further active stages, while the GV-2 feeds a buffer followed by the 'Deep' circuit.
Here is a significant difference: All components in the GV2 tone stack are x10 or x1/10 compared to the original, including the pots. In principle, this should keep the tonal balance the same, but with less load on the previous stage and more signal drive for ongoing stages due to the buffer. For example, GV-2 has a 1M volume pot while the original had 100k. But, just after the volume pot is a cap C22 (new) or C14 (old) which according to the schematics is the same 470pF value. Placed after a 100k pot and the original tone stack, this lightly trims the high treble. But after a stack with 10x the impedance it deeply cuts treble.
If this is correct, then it is strange since the blurb about the GV-2 implies that it contains the tone of the original. I think it may possibly be a mistake, and should have been 47pF to follow the principle of x10 impedance to be followed through.
In any case, it directly relates to this loss of high end in the GV-2, and a popular mod is to remove it. The board is easy to get to and all the components are referenced.
Frequency Response
I used the schematics above to make a simulation model using 5Spice (free download). The main board is all represented, without switching, and using the GV-2 component references to match the actual board and the schematic.
The red circles identify some mods that I've tried (see below). The graphs below are the basic frequency response for small signals (ie below distortion level)
Volume Control:
This is sweeping the volume pot on the stock circuit:
See how the C22 cap is cutting into highs, increasingly at higher volume.
So I took that out. I also bypassed R25 and removed R26. This adds 6db to output volume, with no ill effects that I can find. I also removed C23 from the Deep circuit for a little more highs. Here is the volume plot repeated:
Now there is a few db available of clean transparent boost, even at minimum gain.
Gain Pot
The plots above are at minimum gain. Here it is with the gain pot stepped up:
It shows how gain is more focussed on higher frequencies as gain increases.
Tone controls:
Here are the Treble, Mid, Bass and Deep pots at minimum and maximum;
Treble:
Mid:
Bass:
Deep:
You can see how the mid control is balanced at around 1000hz, and this could no-doubt be tweaked. The Deep control is focussed on very low bass, below guitar range. The hump could be shifted up by decreasing two caps (C16 and C17) in the deep circuit to give more action around 80hz. As stock, it does still have a useful effect on the guitar low notes though.
As usual, the TMB stack is highly interactive, and boosting mids also cuts treble etc. The Deep control is completely independent however.
Conclusion
This is a great fun pedal now.
The knobs are very versatile, though a bit fiddly with 6 stacked into 4 positions. I think you set this pedal for one good sound at a time and use it for that, rather than tweaking on the fly..
I was expecting it to be 'in-yer-face', and it can be, but it also sits nicely in the warm low-gain overdrive range too. The deep control can get almost Fendery. Cranking up though, it sounds very 'Hard Rock' or '80's Metal' to me, so there is a good range here. The tone controls need to be adjusted widely to get to the good places. For me, it has a great tonal range, but others may prefer a bit of the C22 cap put back in, maybe 47pF or 100pF, to smooth it a bit more.
I like it!
http://www.marshallforum.com/threads/say-‘ello-to-the-5-finest-marshall-guv’nor-clones.93122/
It's a pretty looking thing!:
Curved silver finish, embossed Marshall logo, die-cast body and all the gold bling on the knobs.
It's well built and solid, and you get a lot for not much $, including 4-way Eq, a circuit with four opamp stages and true bypass switching.
Testing it out, there's a huge range of tones and it seems to run from clean up to medium-high gain. But for all that, my first impression was it lacks some clear direct-sounding sparkle.
When I get a drive pedal, a lot of the fun for me, apart from playing it, is in working out how it works and how to adjust it to suit what I like.
Although it's quite well known, there is not as much online about it compared to other classic pedals such as TS's and SD-1's. This is the most common diagram online for the GV-2:
It has some suggestions from whoever marked it up. I checked against my pedal, and the component numbers seem to match. It also identifies how the pots and jack inputs are on their own boards. But it's a little hard to follow, a bit blurry and also wires cross that are sometimes joined and sometimes not.
So since other versions are hard to find, it's also a good idea to reference the original version of the Guv'nor, on which the GV-2 was based:
Neither of these are official versions, but all other schematics that I could find online are based on one or other of them.
Circuit Design
Both versions start similarly, with two non-distorting op-amp gain stages, which each include a capacitor in the feedback so bass is de-emphasised at higher gain - good practice in these circuits.
Then the distortion, with hard-clipping to ground using a pair of inverted red LED's. Mods on these components are one of the popular changes. Actually, the quality of tones that the LEDs create seem quite nice to me.
Then comes the passive tone stack, T, M, B, similar to a Marshall amp. At this point, the two versions vary because the original sends a signal out via a volume pot directly after the passive tone stack, with no further active stages, while the GV-2 feeds a buffer followed by the 'Deep' circuit.
Here is a significant difference: All components in the GV2 tone stack are x10 or x1/10 compared to the original, including the pots. In principle, this should keep the tonal balance the same, but with less load on the previous stage and more signal drive for ongoing stages due to the buffer. For example, GV-2 has a 1M volume pot while the original had 100k. But, just after the volume pot is a cap C22 (new) or C14 (old) which according to the schematics is the same 470pF value. Placed after a 100k pot and the original tone stack, this lightly trims the high treble. But after a stack with 10x the impedance it deeply cuts treble.
If this is correct, then it is strange since the blurb about the GV-2 implies that it contains the tone of the original. I think it may possibly be a mistake, and should have been 47pF to follow the principle of x10 impedance to be followed through.
In any case, it directly relates to this loss of high end in the GV-2, and a popular mod is to remove it. The board is easy to get to and all the components are referenced.
Frequency Response
I used the schematics above to make a simulation model using 5Spice (free download). The main board is all represented, without switching, and using the GV-2 component references to match the actual board and the schematic.
The red circles identify some mods that I've tried (see below). The graphs below are the basic frequency response for small signals (ie below distortion level)
Volume Control:
This is sweeping the volume pot on the stock circuit:
See how the C22 cap is cutting into highs, increasingly at higher volume.
So I took that out. I also bypassed R25 and removed R26. This adds 6db to output volume, with no ill effects that I can find. I also removed C23 from the Deep circuit for a little more highs. Here is the volume plot repeated:
Now there is a few db available of clean transparent boost, even at minimum gain.
Gain Pot
The plots above are at minimum gain. Here it is with the gain pot stepped up:
It shows how gain is more focussed on higher frequencies as gain increases.
Tone controls:
Here are the Treble, Mid, Bass and Deep pots at minimum and maximum;
Treble:
Mid:
Bass:
Deep:
You can see how the mid control is balanced at around 1000hz, and this could no-doubt be tweaked. The Deep control is focussed on very low bass, below guitar range. The hump could be shifted up by decreasing two caps (C16 and C17) in the deep circuit to give more action around 80hz. As stock, it does still have a useful effect on the guitar low notes though.
As usual, the TMB stack is highly interactive, and boosting mids also cuts treble etc. The Deep control is completely independent however.
Conclusion
This is a great fun pedal now.
The knobs are very versatile, though a bit fiddly with 6 stacked into 4 positions. I think you set this pedal for one good sound at a time and use it for that, rather than tweaking on the fly..
I was expecting it to be 'in-yer-face', and it can be, but it also sits nicely in the warm low-gain overdrive range too. The deep control can get almost Fendery. Cranking up though, it sounds very 'Hard Rock' or '80's Metal' to me, so there is a good range here. The tone controls need to be adjusted widely to get to the good places. For me, it has a great tonal range, but others may prefer a bit of the C22 cap put back in, maybe 47pF or 100pF, to smooth it a bit more.
I like it!
Last edited:
