CAE Sound preamp CB2 - The one in the Warren Haynes Les Paul

JimiB · Post by **JimiB** » 01 Dec 2008, 17:28

I saw Gov't Mule the other night and Warren sounded better than ever. He was using les gain and sounded killer! I did notice the little toggle by his vol/tone knobs but didnt know what it was. Then I happend on the video of his new built in buffer/preamp
Anybody have any info on this unit?
This is a replica of what John Cutler developed for Jerry Garcia's guitars.
http://www.caesound.com/cgi-bin/cae/info?bufPreamp
Huge pic of it here
http://www.caesound.com/cb2_spec_7.pdf

Found these pics on Ebay claiming to be that unit

JimiB · Post by **JimiB** » 01 Dec 2008, 17:33

Another Pic from the CAE website

CB2 Specs
Frequency response 40Hz to 10K Hz
Output Z = 600 Ohms
Input Z = 475K Ohms
Phase = 180’ Inverting
Power Requirement = 9VDC Duracell MN1604
Current Drain = 5mA
Size in inches = 2 _W X 1 1/2L X 3/4" Tall
Weight = 18grams
Gain = 1X (Unity)

analogguru · Post by **analogguru** » 01 Dec 2008, 20:15

Nobody knows why:

1.) there is only unity gain
2.) the signal inverted
3.) the chip is sanded and there is a current consumption of 5mA

ad 1.) if there would be a gain of 10 (and if desired attenuated at the end of the cable by the factor of 10) the performance of hum (and other noise) introduced by the (long) cable would be better.

ad 2.) the same specs can be achieved in a non-inverting configuration too.

ad 3.) since there is unity-gain the noise of the op-amp does not play an important role (the noise of the resistors are higher) so a TL 061 could be used, resulting in a power consumption of 200µA only, thus giving a 25 times !!! longer battery life.

analogguru

unbeliever · Post by **unbeliever** » 01 Dec 2008, 23:22

The .pdf says 'The goal was to produce a preamp that would boost the signal...', so the unity gain is a bit odd. Maybe it was done this way to avoid a difference in behaviour (with respect to levels, or overdriving inputs on pedals) as compared to a non-buffered signal?

JHS · Post by **JHS** » 02 Dec 2008, 11:20

It doesn't make much sense to install such an onboard buffer in a stock guitar. Any IC-buffer box with a 071/72 or similar IC can do the job too and there's no need for hacking up the guitar.

JHS

sugarinthegourd · Post by **sugarinthegourd** » 02 Dec 2008, 14:57

I've been thinking about installing a SHO circuit onboard in a guitar. Would want to get rid of the crackle on the knob though, as the whole point of putting it on the guitar would be having the gain boost at my fingertips.

Lovepedal Detective · Post by **Lovepedal Detective** » 02 Dec 2008, 16:07

Warren isn't using this as a boost or preamp. He is using it as a buffer to prevent high end loss when rolling down his guitars volume control. It is similar to the way a "treble bleed" cap works on a guitar. The reason it is on a switch is because sometimes he does want the roll off, some times he doesn't.

MKB · Post by **MKB** » 02 Dec 2008, 17:33

I really like the tone of a humbucker guitar when it is not loaded by cable capacitance, it makes the guitar tone much more lively and sparkling. I found this using a wireless unit (Samson Airline) that plugs directly into the guitar jack. So putting a preamp in the guitar at unity gain makes a lot of sense, although flipping the phase doesn't. My Strat can get a little bright sounding through the wireless unit though, but that is what tone controls are for.

I wouldn't recommend putting a SHO in a guitar as it colors the tone too much, unless that is the tone you are looking for.

JimiB · Post by **JimiB** » 02 Dec 2008, 23:04

does this mean the phase would flip when he flips the switch?
Whatever difference this preamp/buffer made I could hear in his playing - thats what made me excited about - he didnt need as much gain which really let his playing shine.

soulsonic · Post by **soulsonic** » 02 Dec 2008, 23:55

JimiB wrote:does this mean the phase would flip when he flips the switch?

Oh yes, that's a good point! But like phase switches on other guitars, it only really makes a big sound change if it's on one of the pickups and both are on at once.

RnFR · Post by **RnFR** » 03 Dec 2008, 00:28

i'm sure that would drive the FOH guy crazy- you get his guitar balanced against the rhythm player's, and then he goes switching it in and out of phase the whole show! i know i wouldn't want to have to deal with that. especially playing in smaller rooms where it the amp and PA sounds could get switched in and out of phase. that's just bad design if you ask me. and don't even get me started about recording...

Fuzzer · Post by **Fuzzer** » 03 Dec 2008, 01:59

Gov't Mule is just one guitar.

sugarinthegourd · Post by **sugarinthegourd** » 03 Dec 2008, 02:13

RnFR wrote:i'm sure that would drive the FOH guy crazy- you get his guitar balanced against the rhythm player's, and then he goes switching it in and out of phase the whole show! i know i wouldn't want to have to deal with that. especially playing in smaller rooms where it the amp and PA sounds could get switched in and out of phase. that's just bad design if you ask me. and don't even get me started about recording...

I don't see how that could have any effect. Out of phase with respect to what? Move your ear a millimeter further from the speaker and the sound will go "out of phase."

Bernardduur · Post by **Bernardduur** » 03 Dec 2008, 09:23

sugarinthegourd wrote:
RnFR wrote:i'm sure that would drive the FOH guy crazy- you get his guitar balanced against the rhythm player's, and then he goes switching it in and out of phase the whole show! i know i wouldn't want to have to deal with that. especially playing in smaller rooms where it the amp and PA sounds could get switched in and out of phase. that's just bad design if you ask me. and don't even get me started about recording...
I don't see how that could have any effect. Out of phase with respect to what? Move your ear a millimeter further from the speaker and the sound will go "out of phase."

You don't a phase change except when it is compared to something else!

RnFR · Post by **RnFR** » 03 Dec 2008, 10:14

i thought they had two guitars. sorry don't listen to hippy rock!

seriously, i don't know what the fuck i was talking about with that pa comment above- one too many "jazz cigarettes" maybe.

but i would try to minimize phase changes as much as possible. and phase issues between two similar guitar tones could come up. i deal with phasing issues all the time, and wouldn't want to compound the problem. i could imagine overdubbing the boosted signal over a nonboosted track. you'd be pretty screwed then- especially if it as "transparent" as they say it is. but then again, with all the inverting amplifiers we use making pedals who knows.

RnFR · Post by **RnFR** » 03 Dec 2008, 10:47

after thinking about this a bit more, it would probably be a good idea to try to keep "clean" type boosters in phase whenever possible. if the tone is going to change anyways- who cares.

Fuzzer · Post by **Fuzzer** » 03 Dec 2008, 13:43

i thought they had two guitars. sorry don't listen to hippy rock!

That was good; And I was going to bring into attention the thing about inverting amplifiers into effects, with so any people using so many effects in different combinations, you never know when the phase is flipped, fatso forgotso.

Ronsonic · Post by **Ronsonic** » 04 Dec 2008, 18:39

I'm guessing TL062 for low current draw, guitar sees a very high Z at the noninverting input of one opamp which drives an inverting opamp for the low Z output. That could give us the specs we see here.

analogguru · Post by **analogguru** » 04 Dec 2008, 18:54

Ronsonic wrote:I'm guessing TL062 for low current draw, guitar sees a very high Z at the noninverting input of one opamp which drives an inverting opamp for the low Z output. That could give us the specs we see here.

1.) It´s a single op-amp (+ on pin 7) so it would be a TL 061
2.) a TL061 doesn´t have 5mA current consumption (only 200µA) as written in the description.

analogguru

bajaman · Post by **bajaman** » 04 Dec 2008, 20:45

probably a TL071 - 5ma current draw or similar

bajaman

CAE Sound preamp CB2 - The one in the Warren Haynes Les Paul [traced]