???BOSS CS-2 Mods???

[shtgoosephour20]

So ive been reading about all these mods that can be done to make good pedals awesome. and im down. i have read that boss pedals, such as the SD-1, have capacitors (two specifically) that drain a significnt amt of tone on or off.  does the CS2 have thse caps? should i replace them? anything else i can do to make this compressor as good as one of those real pricey ones? whats the real difference between these comps?
ive got more questions than i can type. so ill put them up a few at a time.
rock on
martin

[Mark Hammer]

Opinions about the usefulness of these mods vary.  Some folks will swear by them.  Other quite reputable people who have nothing to gain by it will say that if you A/B them you can't hear any difference.

Part of the problem is that some of these "hot-rod" packages like Keeley's include some component *value* changes that will make an audible difference, in addition to some component *type* changes that probably don't.  After a few weeks away, people get their pedal back and they mistakenly attribute whatever change they believe they hear (some of which is *real* change, some of which is auditory memory errors) to *everything* that was done to the pedal.

There are certainly things that can be done to many pedals to reduce noise, like chip changes and resistor changes.  One per cent resistors cost a bit more, and so does working out a system for using 1% where it counts and using 5% elsewhere, so many larger manufacturers just use 5% everywhere.  Sticking a few select 1% components in the front end can sometimes help a lot; especially when lots of gain is applied elsewhere in the circuit.  Many other things that are known to have a beneficial effect on sound in audio systems requiring very wide bandwidth and the capability to keep the appropriate phase relationships between the harmonics and fundamentals of many different sound sources (like you would expect from something that lets you hear an entire drum kit and acoustic guitar *clearly*) simpy have no benefit when processing a single instrument signal headed for an amplifier we *know* will distort and color at least a little bit.

Like most stompbox compressors, the CS-2 has a sort of one-size-fits-all rectifier circuit, which is good but may not be exactly what a particular musician with a particular instrument and playing style needs.  THAT can be changed somewhat.

The CS-2 is more or less the same thing as an MXR Dynacomp and Ross compressor, with a few differences, like the OTA chip used (Roland's higher quality custom BA662 instead of the CA3080 used in the others),  the variable attack/recovery control, and the input and output buffers to accommodate the FET switching.  This means that many mods for the MXR/Ross units will merge nicely with the CS-2 and vice versa.

One of the mods to the MXR/Ross I have suggested that seems to have been favourably received is one to restore brightness (most compressors seem to rob the signal of high end snap).  It can be easily done on the CS-2 as well.  Just ahead of the volume control on the CS-2 are a cap and resistor marked C4 and R3.  R3 is a 10k resistor just about dead center at the control-wire end of the board.  If you put a small value cap in parallel with R3 it will provide a small, but noticeable boost to high end.  Use your judgment to decide what appeals to you most, but a good place to start might be .01uf.  The ideal version might well be a cap and variable resistor straddling the C4/R3 junction and the wiper of the volume pot, bt that starts to get complicated and involves machining and finding a spot for things.  This mod is much easier to do.  If you have a nice small, flat component, you can probably even just pop the back of the pedal, identify the PCB traces, strum, with your guitar plugged in, and keep exchanging caps (by touching their leads to the pads) until you find a value whose tone you like.

[shtgoosephour20]

found that 10k resistor and plan on tryign the different size caps. which resistors should i upgrade to 1%? and what chip should i put in? i heard the CA3080 is good but cant find anything about it. know if thats the right chip or know where i can pick one up? let me know...rock on

[shtgoosephour20]

i find when i use this pedal i get a hum that increase in volume iwht the sustain and level. if i touch my strings or the case of the compressor i can decrease the volume of the hum. any ideas on that one?

[Mark Hammer]

Two things.  

The OTA or gain cell in the CS-2 - the BA662 - is one that Roland has made especially for them.  If you know someone who knows someone who works in the Akihibara in Tokyo, or if you find a dead analog Roland synth from the 1980's, m-a-y-b-e you can score one, but otherwise they are quite rare.  The BA662 is a clear step up from the CA3080 audio-wise, and is a big part of what Roland/Boss used to differentiate the CS-2 from the rest of the stompbox compressors out there.  There are no plug-in substitutes for it as far as I know (although the BA6110, which I think either Pearl or Nobels uses, apparently comes close and is also a SIP package).

Long story short, stick with the guts of the thing.  Nothing to improve there.

The resistors that might be worth swapping for lower noise ones are essentially R13/14/15.  These are located just behind  the BA662 on the side closest to the corner of the board.  There should be some sort of marking there.  

Changing those will reduce the amount of noise that the compressor itself contributes, but from what you describe, the poor noise performance seems to really be a function of what you are feeding the compressor.  My experience is that this aspect is extremely poorly understood by many purchasers and users.  Yesterday, I eavesdropped on a phone conversation between one of the better informed staff at one of the better music stores in town as he explained a compressor to a customer.  The explanation was so misleading, it was all I could do to keep from grabbing the phone away from him.   So if this is what happens under what is typically the best of circumstances, one shudders to imagine the worst of circumstances.

Because they function by cranking the gain up until something requires them to turn it down, compressors need to receive the most pristine, hottest signal you can provide them in order to be as noise free as possible.  Feed them a noisy, hummy signal and they will make it worse.  In your case it sounds like there are some shielding and grounding issues that need to be addressed on your guitar first, before you do anything to the compressor itself.  That might include shielding some wires, or the way in which the bridge and strings are grounded.  Fix that and you will enjoy your compressor more.

[shtgoosephour20]

so is the BA662 a better chip than the CA3080 and i should keep it in the CS-2. its seems i have yet again proved an inability to understand english as i misread ur first reply to favor the CA3080

Roland's higher quality custom BA662 instead of the CA3080 used in the others

but now since ive read in your most recent response

The BA662 is a clear step up from the CA3080 audio-wise

i read it as the Roland is better.

im goign to take ur advice and switch out those resisotrs to reduce the noise from the compressor...to clarify we are talking about a 17k and two 2.2k reistors right?
so now the question is how do i fix the grounding issue on my guitar? all of guitars seem to do this hum....

[shtgoosephour20]

we are replacing 5% resitors w/ 1% resistors...and this is completely independent of carbon film vs carbon composite right? we only need to to distinguish those with regards to OD pedals??

[Mark Hammer]

We are talking about replacing a 10k and two 2.2k carbon film resistors with 1% metal film resistors.  Don't expect any improvement to be huge.

Not knowing anything about the guitars, I obviously can't say anything about the source of hum, but it is a no-brainer to simply mention that single-coil guitars with unshielded wires running between the pickups and pickup switch generally need some type of protection from interference.  If you're like me and every spot in the house where you work with audio has flourescent lights, you need even more shielding and protection from EM hum.

I would suggest hopping over to Ampage and posting your shielding queries on the Guitar Tech forum or, if need be, on the Pickup Makers forum.  There are plenty of guitar techs who do bench repairs for these things in their sleep and can give you a good idea of what works best and cheapest.

[embryo]

Hi Mark,
I read your posting on the subject with great interests as I'm experiencing a similar situation where I wish there was more clarity in my compressor.
Mine happens to be the BOSS CS3 model. Do you have a similar mod to apply to the CS3?

Thanks

Ran

Opinions about the usefulness of these mods vary.  Some folks will swear by them.  Other quite reputable people who have nothing to gain by it will say that if you A/B them you can't hear any difference.

Part of the problem is that some of these "hot-rod" packages like Keeley's include some component *value* changes that will make an audible difference, in addition to some component *type* changes that probably don't.  After a few weeks away, people get their pedal back and they mistakenly attribute whatever change they believe they hear (some of which is *real* change, some of which is auditory memory errors) to *everything* that was done to the pedal.

There are certainly things that can be done to many pedals to reduce noise, like chip changes and resistor changes.  One per cent resistors cost a bit more, and so does working out a system for using 1% where it counts and using 5% elsewhere, so many larger manufacturers just use 5% everywhere.  Sticking a few select 1% components in the front end can sometimes help a lot; especially when lots of gain is applied elsewhere in the circuit.  Many other things that are known to have a beneficial effect on sound in audio systems requiring very wide bandwidth and the capability to keep the appropriate phase relationships between the harmonics and fundamentals of many different sound sources (like you would expect from something that lets you hear an entire drum kit and acoustic guitar *clearly*) simpy have no benefit when processing a single instrument signal headed for an amplifier we *know* will distort and color at least a little bit.

Like most stompbox compressors, the CS-2 has a sort of one-size-fits-all rectifier circuit, which is good but may not be exactly what a particular musician with a particular instrument and playing style needs.  THAT can be changed somewhat.

The CS-2 is more or less the same thing as an MXR Dynacomp and Ross compressor, with a few differences, like the OTA chip used (Roland's higher quality custom BA662 instead of the CA3080 used in the others),  the variable attack/recovery control, and the input and output buffers to accommodate the FET switching.  This means that many mods for the MXR/Ross units will merge nicely with the CS-2 and vice versa.

One of the mods to the MXR/Ross I have suggested that seems to have been favourably received is one to restore brightness (most compressors seem to rob the signal of high end snap).  It can be easily done on the CS-2 as well.  Just ahead of the volume control on the CS-2 are a cap and resistor marked C4 and R3.  R3 is a 10k resistor just about dead center at the control-wire end of the board.  If you put a small value cap in parallel with R3 it will provide a small, but noticeable boost to high end.  Use your judgment to decide what appeals to you most, but a good place to start might be .01uf.  The ideal version might well be a cap and variable resistor straddling the C4/R3 junction and the wiper of the volume pot, bt that starts to get complicated and involves machining and finding a spot for things.  This mod is much easier to do.  If you have a nice small, flat component, you can probably even just pop the back of the pedal, identify the PCB traces, strum, with your guitar plugged in, and keep exchanging caps (by touching their leads to the pads) until you find a value whose tone you like.

[czech-one-2]

Old thread revival!
I added a .01uf cap over the 10k that Mr Hammer recommended,and it did add the perfect amount of snap and trebel enhancement!
Now, is there a way to just add a little more volume to my CS-2? I tend to use it with with the volume at max and the compression at 9 o'clock,but I'd like to get a little more boost out of it.I dont want to change the level pot to a higher value.

[Chousy]

Two things. 

The OTA or gain cell in the CS-2 - the BA662 - is one that Roland has made especially for them.  If you know someone who knows someone who works in the Akihibara in Tokyo, or if you find a dead analog Roland synth from the 1980's, m-a-y-b-e you can score one, but otherwise they are quite rare.  The BA662 is a clear step up from the CA3080 audio-wise, and is a big part of what Roland/Boss used to differentiate the CS-2 from the rest of the stompbox compressors out there.  There are no plug-in substitutes for it as far as I know (although the BA6110, which I think either Pearl or Nobels uses, apparently comes close and is also a SIP package).

Long story short, stick with the guts of the thing.  Nothing to improve there.

The resistors that might be worth swapping for lower noise ones are essentially R13/14/15.  These are located just behind  the BA662 on the side closest to the corner of the board.  There should be some sort of marking there. 

Changing those will reduce the amount of noise that the compressor itself contributes, but from what you describe, the poor noise performance seems to really be a function of what you are feeding the compressor.  My experience is that this aspect is extremely poorly understood by many purchasers and users.  Yesterday, I eavesdropped on a phone conversation between one of the better informed staff at one of the better music stores in town as he explained a compressor to a customer.  The explanation was so misleading, it was all I could do to keep from grabbing the phone away from him.   So if this is what happens under what is typically the best of circumstances, one shudders to imagine the worst of circumstances.

Because they function by cranking the gain up until something requires them to turn it down, compressors need to receive the most pristine, hottest signal you can provide them in order to be as noise free as possible.  Feed them a noisy, hummy signal and they will make it worse.  In your case it sounds like there are some shielding and grounding issues that need to be addressed on your guitar first, before you do anything to the compressor itself.  That might include shielding some wires, or the way in which the bridge and strings are grounded.  Fix that and you will enjoy your compressor more.

Is there any other resistor worth to change to metal film besides R13, R14, R15?

[Lew-Dawg]

Front row seats for this one!

Cheers

Lewis