What compressor to pair with 15v Pork Barrel

[Guitarmatt]

I've built but not yet boxed a Pork Barrel chorus. I'd like to box it with a road rage to run at 15v, plus a compressor so I'll have one stomp shopping for 80s cleans.  I'll be using a small bear bare box for my enclosure so I'll have plenty of room. What compressor would you guys suggest to pair with the Pork Barrel?  Is there a compressor I can run at 15 volts since I'll have it available from the road rage?

Extra info: I already have an Afterlife, an Orange Squeezer and an Xotic SP. I tried out the PB and Afterlife together which is what inspired this idea. If I can't come up with another good option I'll just order another Afterlife board. Any idea if that can run on 15v? I'm also interested in the Engineer's Thumb if I can find a layout small enough to fit in the biz with all that other stuff. A three way switch for chorus only, comp and chorus, comp only would be cool too.

[mjcyates]

Well my suggestion was going to be the Afterlife. I think it sounds great.

[rullywowr]

Love the 80's and really like your concept.  The afterlife is a great compressor.  I also have a new layout for the Demeter Compulator called the "Demented Compressor".  Uses a vactrol and sounds really good.  Two knobs, easy build.  I have just verified, and do have boards available.  1.9" x 1.6"

[Guitarmatt]

The Demeter comp looks interesting, but am I right in thinking it would be more subtle than the Afterlife? If anything I'd like to go with a comp a bit more pronounced than the Afterlife to add a bit more attack pop.

Can the Afterlife run on 15 volts?

[Guitarmatt]

Taking a look at the Road Rage PDF I see you can use the regulated 15 volt out and the 18 volt out simultaneously. So I have the option to run my compressor section at 18 volts if I find a suitable comp.

[Clayford]

There's absolutely nothing that says you can't use 9v for the compressor. Brian has even included an extra 9v pad on both versions of the roadrage for just such an occasion. You're most likely looking for something that can get squishy and Ross-ish?

Jon's (Midwayfair) Bearhug comes to mind as being able to do both Afterlife and Ross modes, and then there's the Engineer's Thumb. No, my dear Watson not the novel. It's a Merlin B design and also very cool. Added bonus, Jon demo's the Thumb as well in the link! Jon also suggests changing the Ratio pot to a 500k vs 1M for more usability. Mark's layout is the 2 knob version, but in reading his notes underneath you can easily sus out exactly what to do if you desire the 5 knob job.

IANAEE, so I'm not sure if either of my suggestions can be used at 15v. I have been known to use the pork barrel and an Engineer's Thumb when the need for hairspray and spandex arises.

[Guitarmatt]

Thanks Clayford for the input. Of course like you say 9v is still an option. I'm wondering if running a higher voltage compressor could add some clean headroom to the whole box. I'd like to build this as versatile as possible, since it may also see use with my acoustic in the fx loop of my lr baggs padi.

[Clayford]

I dunno.... From Merlin's spiel:
Up to five times more headroom than a Dynacomp

Check out the thread on it over at DIYSB

[midwayfair]

IANAEE, so I'm not sure if either of my suggestions can be used at 15v. I have been known to use the pork barrel and an Engineer's Thumb when the need for hairspray and spandex arises.

Both of these will sound pretty almost exactly the same at 15V or 18V, but there may be a resistor or two that needs to be changed in each.

I do know that the Bearhug will produce a little more voltage gain into the envelope, which means it would compress more than it needs to, so I've recommended running it at 9V, but if someone were to really want to run it on 18V, I could suggest some changes. The primary benefit to adding voltage to a MOSFET is extra brightness, but any added brightness you'd get from a MOSFET running at 18V will most likely be swallowed by the gate-drain bypass cap.

For the thumb, the differential input voltage of the LM13700 is only 5V. So I think there's a possibility you'll distort it (at least before the compression kicks in) on a higher voltage depending on what the Tl072 spits out at it. I'd test it first.

[Guitarmatt]

Thanks for pitching in Jon. I just found your mini layout for the Engineers Thumb. I think Im going to build one to try it out. I'm impressed by how quiet the circuit is at idle in demos. Sitting right in front of a chorus that would help reduce swooshing sounds during rests. I see there are two resistors that can be replaced with pots for longer attack and shorter release. Those together would allow me to dial in a bit more pop on the transients in quick funky rhythms or intricate fingerpicking, is that correct?

To summarize at this point: I don't think I'll worry about running the comp at a higher voltage, and the compressor sound I'm looking for is more on the bright and snappy side.  My Xotic SP covers the classic squash sounds.

Another comp question: Am I right in thinking that the Afterlife has a longish release while the Orange Squeezer's release is comparatively short?  That's what my ears seem to be telling me. How does the ET compare?

[midwayfair]

Thanks for pitching in Jon. I just found your mini layout for the Engineers Thumb. I think Im going to build one to try it out. I'm impressed by how quiet the circuit is at idle in demos. Sitting right in front of a chorus that would help reduce swooshing sounds during rests. I see there are two resistors that can be replaced with pots for longer attack and shorter release. Those together would allow me to dial in a bit more pop on the transients in quick funky rhythms or intricate fingerpicking, is that correct?

To summarize at this point: I don't think I'll worry about running the comp at a higher voltage, and the compressor sound I'm looking for is more on the bright and snappy side.  My Xotic SP covers the classic squash sounds.

Another comp question: Am I right in thinking that the Afterlife has a longish release while the Orange Squeezer's release is comparatively short?  That's what my ears seem to be telling me. How does the ET compare?

I would recommend keeping the attack as short as possible in the ET and just turning on the treble bypass. It can get so extreme that a longer attack might make things sound a little weird. It really excels at what it does in the stock settings, I think, and I also think that you'll find that it's every bit as good or better than the Xotic for classic squish.

The Afterlife's decay is ... difficult to determine, because there's no parallel resistor, but it's over 1 second almost all the time.

The Orange squeezer's decay is 470mS. That's the 4.7uF capactor * 100K parallel resistance = time delay in milliseconds.

[Guitarmatt]

Great info. I think I'll build an ET with all the bells and whistles to see what i like and then pare down the options before boxing if i find i can do without some.  I'll put the Pork Barrel in a temporary enclosure and try it with various comps over the next few weeks while I build that ET and finish the final enclosure.

[Clayford]

Glad to have pointed you in the right direction! One last thing, if you add the 1M pots for the Attack and Decay, Merlin suggests a 220k in series with the Release pot.

[claytushaywood]

IANAEE, so I'm not sure if either of my suggestions can be used at 15v. I have been known to use the pork barrel and an Engineer's Thumb when the need for hairspray and spandex arises.

Both of these will sound pretty almost exactly the same at 15V or 18V, but there may be a resistor or two that needs to be changed in each.

I do know that the Bearhug will produce a little more voltage gain into the envelope, which means it would compress more than it needs to, so I've recommended running it at 9V, but if someone were to really want to run it on 18V, I could suggest some changes. The primary benefit to adding voltage to a MOSFET is extra brightness, but any added brightness you'd get from a MOSFET running at 18V will most likely be swallowed by the gate-drain bypass cap.

For the thumb, the differential input voltage of the LM13700 is only 5V. So I think there's a possibility you'll distort it (at least before the compression kicks in) on a higher voltage depending on what the Tl072 spits out at it. I'd test it first.

I've definitely had good results running the diamond compressor with 18v.  does better with higher output pickups... would this not be the same for the afterlife?

[midwayfair]

I've definitely had good results running the diamond compressor with 18v.  does better with higher output pickups... would this not be the same for the afterlife?

It depends on how big an input signal we're talking about, and also, for the afterlife, how low an on resistance your vactrol has.

The diamond has two stages -- an input stage, and then a gain recovery stage, which also serves as the split-off point for the envelope detection.

The LDR in the Diamond is one leg of a voltage divider (volume control) between the two stages.

The Afterlife only has one gain stage, and it's the same gain stage whose gain is controlled by the LDR. If your LDR can drive down to one or two K, it doesn't matter how big the input signal is until it reaches 4.5V peak to peak, which is HUGE, because your input signal will compress to 1x. (If you guessed that this means that really big input signals have a lower ratio, you win a cookie!)

The Diamond does not really have this benefit. You could still overdrive the first stage; also, the thing is presumably set up so that you can't ground out the signal, so big input signals can also overdrive the make-up gain stage more easily.

(The Bearhug is actually the easiest of the three to distort, but it functions more closely to the Afterlife.)

But again, this does depend on several factors with how the afterlife in question is built.