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[agedhorse]

Hi Agedhorse.

I saw on the Acoustic Guitar Forum (where I am not currently a member) that you were involved in the CTP-2 preamp design. I thought I'd search Talkbass to see if I could find anything and up popped this several years old thread. I'm wondering if you might be able to help me?

A friend has asked me to look at his Takamine TAN15C which has the CTP-2 in it. It often makes a 'rustling' noise when it is plugged in. I've disconnected, cleaned and reconnected all the plugs and cleaned the end pin jack, but it is still doing it. If you drop the volume on the preamp to zero, the noise goes away, so I'm thinking it isn't a problem in the wiring from the preamp to the end pin jack (unless its a problem in the power on switch circuit). If you unplug the input from the transducer the noise is still there so I'm thinking it isn't the transducer or its wiring, so it must be in the preamp. Sometimes if you unplug it and plug it back in the rustling stops.

I've read a few comments about the high noise floor of the CTP-2, but I can't imagine it would have been shipped making this much noise, and as I said, sometimes it doesn't do it. I've also read comments about these preamps being high maintenance and not particularly long lasting. I'm wondering if you have any thoughts on what might be going on here. I'm reluctant to give it back to my friend still not working properly, but replacing the preamp is a pricey exercise, even if I downgrade it to a simpler one (CT4D being one option).

I realize that your involvement in the design of this preamp was a long time ago, but I thought is was worth asking when I saw your username on the other forum. I always appreciate your input to discussions here on Talkbass.

Thanks
Warren

The noise floor on the CTP-2 is lower than on the other versions, it's really very quiet, should not be making those noises.

There's not much you can do other than changing the tube, it's a 12AU7, I don't remember which brand but I recall that the brand and specific model was important. A 12AT7 or 12AX7 will not work in that circuit.

That's about all I remember.

 

[Lowendtech]

Hi Agedhorse.

I saw on the Acoustic Guitar Forum (where I am not currently a member) that you were involved in the CTP-2 preamp design. I thought I'd search Talkbass to see if I could find anything and up popped this several years old thread. I'm wondering if you might be able to help me?

A friend has asked me to look at his Takamine TAN15C which has the CTP-2 in it. It often makes a 'rustling' noise when it is plugged in. I've disconnected, cleaned and reconnected all the plugs and cleaned the end pin jack, but it is still doing it. If you drop the volume on the preamp to zero, the noise goes away, so I'm thinking it isn't a problem in the wiring from the preamp to the end pin jack (unless its a problem in the power on switch circuit). If you unplug the input from the transducer the noise is still there so I'm thinking it isn't the transducer or its wiring, so it must be in the preamp. Sometimes if you unplug it and plug it back in the rustling stops.

I've read a few comments about the high noise floor of the CTP-2, but I can't imagine it would have been shipped making this much noise, and as I said, sometimes it doesn't do it. I've also read comments about these preamps being high maintenance and not particularly long lasting. I'm wondering if you have any thoughts on what might be going on here. I'm reluctant to give it back to my friend still not working properly, but replacing the preamp is a pricey exercise, even if I downgrade it to a simpler one (CT4D being one option).

I realize that your involvement in the design of this preamp was a long time ago, but I thought is was worth asking when I saw your username on the other forum. I always appreciate your input to discussions here on Talkbass.

Thanks
Warren

Plugging in the cable to the output jack turns the preamp on. The “rustling” sound you’re hearing is the tube warming up.
Turn the volume down before you plug in and you’ll be fine.
I have a Tak with that pre in it. It’s awesome.

edit; that’s what I get for posting something I wrote 1/2 hr ago without checking for new messages. lol.

 

[agedhorse]

Yes, it can make some noise during warm-up. The CTP-2 has an added warm-up LED that the other versions don't have, but they all make noise warming up. I understood the question to be all the time???

The CTP-2 project was pretty heavy duty, there's a LOT going on inside that preamp.

 

[wunnorf]

Yes, it can make some noise during warm-up. The CTP-2 has an added warm-up LED that the other versions don't have, but they all make noise warming up. I understood the question to be all the time???

The CTP-2 project was pretty heavy duty, there's a LOT going on inside that preamp.

I don't have the guitar with me at the moment. Maybe it is only on warmup. Thanks for the help.

 

[wunnorf]

As this has absolutely nothing to do with bass, I'd suggest that you PM him.

Fair enough I guess, but I got some information from others on the forum and I was replying to a post by Agedhorse about the CTP-2 preamp, which is primarily used in guitars I think. A Google search tells me it is/was in the TB10 bass, which looks like an interesting beast.

 

[agedhorse]

I don't know how many were actually used in the bass models, but it certainly could have been used that way.

 

[SJan3]

Fair enough I guess, but I got some information from others on the forum and I was replying to a post by Agedhorse about the CTP-2 preamp, which is primarily used in guitars I think. A Google search tells me it is/was in the TB10 bass, which looks like an interesting beast.

Please, take no offense but it was out of context. I'm glad you got the info you needed.