Custom Build: Bass Boost & Compressor - Advice Sought

[Strange]

Hello all. I have been a member of this forum for a long time now and have learned a great deal from the forum. Fot that I would like to thank everyone. I was hoping I could also have a little expert insught on a project I am going to start in the very near future.

A friend of mine is having a birthday in a few months and I wanted to build him a custom pedal. Several years ago I recall him mentioning that he would really dig a boost and compressor in a single enclosure. He uses a Green head and plays heavy tunes (stoner, doom, metal, etc). Knowing my friend has very little knowledge of pedals - combined with the fact that I am not a bass player - I am at a loss as to what combo I should throw in the box. I am also curious as to the 'rules' for placement: does the comp go before the boost or vice versa?

Thoughts? Thanks in advance!

[Mark Hammer]

A compressor detects the level of the signal, and then adjusts gain in response.  If it detects a strong input signal, it turns the gain way down.

So, although a booster and compressor CAN coexist in a single pedal (or as two pedals in a row), turning a booster on in conjunction with a compressor will not produce anything you'd want if the booster comes before the compressor.  This means that any booster you include should be situated after the compressor.  That way, he can use the compressor OR the booster, and if he chooses to use both at once, it will not present any problems.

But consider that compressors can also serve as boosters.  In fact, waaaayyyyyyy back in the day, in the late 70's, my booster WAS a compressor.  It is possible to simply select between two different output levels of the compressor to achieve a boost.  And given that many bass players (as evidenced by many bass amps) will leave a limiter or compressor on all the time, that may be just the thing for your friend.

I'll suggest some variant of the Orange Squeezer for the job, since that has a fairly quick recovery time, and is easily optimized for bass.  Since it uses only one aop amp, and many existing layouts employ a dual op-amp with one half unused, you could easily co-opt that other unused op-amp for selectable boost duty.

[Gurner]

I'd have thought a half wave rectifier type compressor (as used in the Orange Squeezer) would not be optimum for a bass.... depending on the components selected, there can already be a fair degree of ripple on the cap (& ultimately, jfet gate) ...hurling 40Hz or less in there is not gonna help matters wrt ripple.

I'd always looked at the main point of a compressor being to boost your guitar 'in the mix' (be it on stage or in the studio) ....ie it removes dynamic range allowing you to crank up the overall resulting flattened level higher in the mix. The orange squeezer has a potential gain of about 20x....I call that a boost!

[Mark Hammer]

In principle, you are right.  But the ripple issue is really more pertinent when there is an intent to use a compressor for "sustain", as opposed to peak limiting, sionce ripple occurs most during the sustain/decay phase of the string's vibrations.  The nice thing about the OS is that it is a get-in-get-out-quick circuit.  As long as one uses it that way, ripple should be of acceptably low levels.

[Strange]

My first inclination was to arrange the pedal with the compressor feeding into the boost. However, I know a few players that like compressors at the end of their chain to be used as an effect. I have used a compressor in recoding applications both in a traditional capacity and as an effect but I have never used it with a guitar. I forgot to mention that he plays in dropped tuning alot - C# if I am not mistaken. I was assuming that my friend was looking for a compressor to tighten up his tone, add a little punch and reign in the sonics somewhat.

After spending an hour on Google the Orange Squeezer seems to be popular with bass players. I can always modify the circut with the Tonepad mods credited to Mr. Hammer. By all accounts it seems to be a rather subtle compressor. Regardless, I have lots of time on my hands and I am open to suggestions.

I have read much disucssion on the benefit of an external bias control. However, I cannot see this being a good idea. I would think that the pedal should be biased properly and left. It seems an external pot would only lead to more cases of 'user error' than any potential benefits. As opposed to a bias control I was thinking that a blend feature would be something that could add additional flavour to the build. My thoughts were that adding a blend control would help to diversify tonal options along with providing the ability to mimic different compression settings. I am not sure this would be all that useful with the OS circut being subtle. Would this be something a bass player could find useful in the above noted stoner/doom application?

Lastly, since my friend is after the extra heavy tone, should I be using a clean or coloured boost? I want it to be useable so my first inclination was to let the amp provide the distortion with the help of a clean boost. Again, my lack of familiarity with the bass is obvious. Recomendations for a bass boost circut would be appreciated.

[23]

IM no genius at building pedals but I do play bass.........mostly slap but I do use my tone control on the bass to produce a heavy "dub" sound so what I say may help some. I recently have been on a search for a compressor and after much trial and error I have settled on a MXR dyna comp with an "attack" toggle switch. The orange squeezer to me is to subtle and really just adds a bit of "sparkle" to the sound were as the dyna comp/ ross levels the peaks out and makes for a nice smooth sound and really works for sustain and as a booster if needed......... for a booster, believe it or not I use a NPN fuzz face with a bias knob so you can add the amount of fuzz you want while still having the fuzz and volume control set pretty high or he can blast the bias and add fuzz for an even more heavy sound.

Like I said before there are alot more knowledgeable people on here that can get way more technical but at the same time I know what I like so I find some relevance in what I'm saying. In reality its all very subjective and  what i find useful your friend may not. I believe its was Mark M or hammer that came up with the attack toggle and its readily available on here. I actually tested comps set up for guitar......... mostly being a keeley 2 knob comp and I loved it on bass... but found the dyna (again borrowed from a guitarist) to be a bit more to my liking..... Im trying to avoid such cliches as spongy, squish, etc.... More so if he plays anything fast he will want a fast compressor for recovery.

hope this helps some.

sands

[Mark Hammer]

My first inclination was to arrange the pedal with the compressor feeding into the boost. However, I know a few players that like compressors at the end of their chain to be used as an effect. I have used a compressor in recoding applications both in a traditional capacity and as an effect but I have never used it with a guitar. I forgot to mention that he plays in dropped tuning alot - C# if I am not mistaken. I was assuming that my friend was looking for a compressor to tighten up his tone, add a little punch and reign in the sonics somewhat.

After spending an hour on Google the Orange Squeezer seems to be popular with bass players. I can always modify the circut with the Tonepad mods credited to Mr. Hammer. By all accounts it seems to be a rather subtle compressor. Regardless, I have lots of time on my hands and I am open to suggestions.

I have read much disucssion on the benefit of an external bias control. However, I cannot see this being a good idea. I would think that the pedal should be biased properly and left. It seems an external pot would only lead to more cases of 'user error' than any potential benefits. As opposed to a bias control I was thinking that a blend feature would be something that could add additional flavour to the build. My thoughts were that adding a blend control would help to diversify tonal options along with providing the ability to mimic different compression settings. I am not sure this would be all that useful with the OS circut being subtle. Would this be something a bass player could find useful in the above noted stoner/doom application?

Lastly, since my friend is after the extra heavy tone, should I be using a clean or coloured boost? I want it to be useable so my first inclination was to let the amp provide the distortion with the help of a clean boost. Again, my lack of familiarity with the bass is obvious. Recomendations for a bass boost circut would be appreciated.

Here's a suggestion, and something your friend will likely appreciate very much: build in an external loop.
So, imagine you have a compressor of some sort, and a booster.  We've already established more or less that the booster is optimally placed after the compressor.  Okay, now let's stick a send and receive jack between the compressor and booster.  You can either elect to simply use a pair of switching (closed-circuit) jacks such that it's a direct path from compressor to booster if nothing else is plugged in.  Or you can elect to stick a loop-select switch to engage the loop at will.

Doing something like this would suggest use of a 1590BB box (or maybe even one of those newfangled trapezoid boxes!) sothat there would be room for two or even 3 stompswitches, plus room along the rear skirt for the send/receive jacks.

Think about it, though don't feel hemmed in by it.  I'll simply end by noting that I can't imagine a player alive who does NOT find utility in a loop-select.

[23]

If he likes the compressor enough.... Ive simply put a compressor in the effects loop and left it on while running the booster (FF) in line between bass and amp in. Simple.

But Mr. Hammer does have a good idea......

[Gurner]

If he likes the compressor enough.... Ive simply put a compressor in the effects loop and left it on while running the booster (FF) in line between bass and amp in. Simple.

??

Unless I'm not grasping the point, using via a send/return loop won't compress/act on the whole signal, but an element of the signal  (dry) is sent, compressed & mixed in as a return (wet) - I'm obviously missing the point of using a compressor in that manner....the original signal will be output unfettered from a compression perspective (as it's simply the original mixed with a dynamically compressed copy...there's no compression 'win' in that scenario as the original signal will still hold the full dynamic range)


Compressors are normally an 'insert' effect (vs send/return)...I guess you could use the compressor in a 100% wet scenario, but still pondering (albeit with a few cans of falling down water in my belly)  why anyone would go this way.

[amptramp]

Gotta go along with Gurner in that a halfwave rectifier type of compressor is not optimum.  You may get a different effect depending which direction the string is plucked and the output will vary depending on whether you have a phase inversion ahead of the compressor.  A DOD280 will work if all the coupling capacitors are increased in value.  Values I would use are:

Input coupling from 0.01 µF to 0.05 or 0.1 µF and I prefer 0.1 µF just to couple the input to the guitar a bit better and reduce low-frequency noise
Connected to gain pot from 0.05 µF to 0.5 µF
Output capacitor to output volume control from 0.05 µF to 0.5 µF
Capacitors to the rectifying transistors (there are two of them, both 0.05 µF) can stay the same or go up to 0.1 µF, but going up will increase the time constant of the gain recovery.

In all cases, where I call for a 0.05 or 0.5 value, a 0.047 or 0.47 will do - some manufacturers make "5" a standard multiplier whereas others use "4.7" because it fits the logarithmic scale of standard values.  This would give symmetrical response for both signal polarities.  Adding gain ahead of the compressor would result in increased compression, so this is probably preferable to gain afterwards, depending on the amplifier sensitivity.  Of course, you could add a gain stage both before and after the compressor.

[Mark Hammer]

My intent with the inclusion of a loop is simply that the one box could provide compression all on its own, compression+boost, boost alone, loop select+boost, loop alone, or compression+loop+boost.  That's pretty dang flexible if you ask me.

It is true that some things may not work quite as well after compression.  So, reducing the dynamic range via compression may impede more pronounced effects on autowahs.  But nothing says you have to crank compression up full.  And since a great many autowahs do not include an output level control (came with chorus, flanger, et al), being able to stick them just ahead of a boost allows one to use the boost to provide volume adjustment at the tap of a toe.

[Ben N]

Mark, what's your Dad doing here?

[23]

Google it, it can affect how the comp responds, verses out front............ matter of taste really. Try both.

[Strange]

I appreciate the comments. I am going to do up a few PCBs is a few days and so far I am leaning towards an MXR design using a Dunacomp into a Micro Amp.

Again, I am not a bass player and as such I have no experience running either of these with a bass.

Any other suggestions or comments?

[23]

Yeah use MPSA18's  in the MXR comp, they provide a cleaner sound..................

[Strange]

Yeah use MPSA18's  in the MXR comp, they provide a cleaner sound..................

Thanks - I am going with the Saffron version so the MPSA18 will be on the board.