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Bartolini 'The Chip'

M

mebass5

Nov 27, 2005
109
6
#1
Does anyone out there have any experience using one of these? I'm having a bass built (with Bart Jazz pickups and Pensa pre) and I was wondering if putting one of these in would give me additional gain without any additional noise? Is it a pre in itself, or is it just an adjustable gain pot? Thanks!
 
#2
Not sure if you received any info on this! I don't have any first hand experience with this device. I do know that it is considered a one transistor preamp with a gain of 100. Just happen to be reading a guitar hot rodding book, and came across this thread cross ref searching on the same subject I was reading, ha ha that's way out there don't ya say! It also offers treble, mid, and bass tone controls and parametric equalization. It is also known to not drop off the high ends at high gain levels like the op amps are known for doing. That's all I came across on this Bartolini "Chip" (Donald, Brosnac;"Guitar Electronics for Musicians" pg87)
 
#3
I have one! I bought it back in 1977. It's a nice sounding preamp, but it doesn't handle pickups with too much output. It's made low output pickups. It used to clip with the Hi-A 2B humbucker I had in my Rickenbacker.

You can control the gain, and do other things with it as well, like mid boosts and even use it as a fuzz. The un-boosted gain of the TC1 is 8X, so it lacks headroom. Makes a nice fuzz though.

The other thing is the input impedance is 300K, so it doesn't give that high end sparkle like JFET buffers do, but it sounds very natural.

I tried using it recently with some medium output pickups, and padded down the input, but it picked up a lot of RF noise.

They make other versions that work with higher output (read; normal) pickups.

Here's the old hand drawn and typed instructions that came with it. I have the TC1.

Invalid Link Removed
 
#4
There are three gain versions of Bartolini's "The Chip" preamps, and they come in single and dual formats.
  • The TC1/TC2 are the highest gain versions (for use with weak pickups). TC1 is a single preamp and the TC2 is dual.
  • The TC3/TC4 are medium gain versions. TC3 single / TC4 dual.
  • The TC5/TC6 are the lowest gain versions (for use with high output pickups). TC5 single / TC6 dual.
"The Chip" preamps provide straight gain. Adding external components can provide tone shaping.
 
#5
Old thread, I know, but did you get this to work in your bass?

I have one that I'm thinking of putting into my jazz bass. It's a TC5, which has a lower minimum boost than the TC3.

The literature says that you can boost the mids and treble with it, but I'm wondering if you could boost the bass frequencies if you wanted to. Seems like you'd just use different caps, but I'm wondering if there is a reason that they don't mention it as a bass boost in the info..
 
#6
deepestend said:
The literature says that you can boost the mids and treble with it, but I'm wondering if you could boost the bass frequencies if you wanted to. Seems like you'd just use different caps, but I'm wondering if there is a reason that they don't mention it as a bass boost in the info..
Click to expand...

Invalid Link Removed does show a bass boost but not the kind most people mean when they talk about bass boost. In fact the mid boost is not what most people mean by that term either. From what the data sheet says I suspect that this is a single low noise transistor amplifier stage with an unbypassed "emitter" resistor (for all I know the transistor is a FET in which case it would be a "drain" resistor). This kind of amplifier will give you a fixed gain over a broad range of frequencies, which is what Bartolini claims. If you add a capacitor to the "boost" lead you will increase the gain at higher frequencies and as you increase the size of the capacitor the frequency at which the gain is boosted goes lower and lower but it is also boosted by the same amount at all frequencies above the boost cut in frequency. If you make the capacitor big enough you can extend the boost range to and below the bass frequencies. And if you use a resistor in series with the capacitor you can control the amount by which the gain is boosted. You can see all of this in the frequency response graph at the bottom of the page linked above.

When most people talk about bass, mid, or treble boost they are talking about a boost that occurs at just one of those frequency bands (however the bass, mid, and treble bands are defined in the application under discussion which will be different for bass and regular guitars). From the looks of it this preamp will just boost the treble if you use a small capacitor. If you use a larger capacitor you can boost the mids and the treble. If you use a large enough capacitor you can boost bass, mid, and treble. But you cannot boost just bass or just mids.

Now in theory any gain block can be used to boost any frequency band on its own so with some work you can probably use the device to boost any band that you like. Bartolini does not describe how to do that and since they do not provide a schematic of their amplifier I can't help you with that either.

Ken
 
#7
Ken,
Thanks for the insightful post on this preamp. I've been going back and forth and studying the sheets and I'm starting to think that perhaps the best application of this little amp is not to try to enhance any band in particular, but to use the: TC3 WITH VARIABLE BOOST IN A STRAT diagram and use a push/pull pot to turn the amp on and off and then the boost level pot from the strat diagram to control the amount of boost. Seems like it would then be like more of a straight up boost type pedal but I'd be able to control it on the bass. What do you think of this application? Would it still boost the frequencies equally? Would I need to add a 10mfd cap?
 
#9
#10
deepestend said:
I've been going back and forth and studying the sheets and I'm starting to think that perhaps the best application of this little amp is not to try to enhance any band in particular, but to use the: TC3 WITH VARIABLE BOOST IN A STRAT diagram and use a push/pull pot to turn the amp on and off and then the boost level pot from the strat diagram to control the amount of boost.
Click to expand...

Bartolini says that it works and from what little I can second guess from their data sheet I tend to agree with them. Your boost will be down about 2dB at the open E string (~40Hz) with a 10uF cap so you might want to consider a 22 or 33uF cap instead, especially if this is going into a 5er.

Ken
 
#13
I have a TC5 combined with 2 Lane Poor pickups and a passive tone roll off control. Lane Poor pickups don't have a lot out output and the TC5 gives the bass an over all output of a passive P or J bass. The bass also has a push/pull TC5 bypass in case the battery or the TC5 dies, I have had a TC5 die and need replacing.
 

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