Pre-amp problem/question

[The Grudge]

Hi, thanks for any input. I have just recently added a power amp into my system. I am now using my integrated as a pre-amp. I did have some audioquest inserts (I really do not know their proper name :o ) filling the main in and pre out plugs on the back. Now of course on the pre out I have the interconnects going to the normal main in on the power amp. Would I still have the audioquest insert :o on the pre in the main in? I was told not to have them there, but I am experiencing sound trouble and I am looking at all possibilities so I thought I would start there.

The power amp was a used unit, but the seller stands behind it very firmly and will pay to have it fixed if there is a problem with it. I experience broken crackling sound intermittently in either channel, one channel at a time. Sometimes the sound in one channel disappears completely for a short time. I am not sure if perhaps my integrated has a problem with its pre-out circuitry. Right up to a few hours before hooking up the power amp I had flawless performance from my integrated so I am confused. That said, my integrated was never used as a pre-amp before so I would not have known of any problem. Is the circuitry on the integrated pre-outs the same as the circuitry used when it was acting as an integrated. Thanks for any thoughts.

:)

[Feanor]

Hi, thanks for any input. I have just recently added a power amp into my system. I am now using my integrated as a pre-amp. I did have some audioquest inserts (I really do not know their proper name :o ) filling the main in and pre out plugs on the back. Now of course on the pre out I have the interconnects going to the normal main in on the power amp. ... my integrated was never used as a pre-amp before so I would not have known of any problem. Is the circuitry on the integrated pre-outs the same as the circuitry used when it was acting as an integrated. Thanks for any thoughts.

:)
Your description is just a let vague and I'm not totally familiar with the NAD integrated. I assume the Audioquest "inserts" are, in fact, jumpers that were connecting the pre outs to the main ins: is this correct??? (That being the case, I'm having trouble understanding how they would remain in the main ins, so I have to ask).

Assuming the inserts are jumpers, then it's pretty clear that exactly the same circuity in the integrated is driving the new power amp as was driving the integrated's main section. That does cast some suspicion on the new power amp. (However first make sure all connections are secure: interconnects, speaker connections, and power cords to both units.)

[The Grudge]

Thanks Feanor, I can update the situation now. All the connections were fine, really nothing complicated as I'm sure you know. I am sure it is not the power amp at all, but rather nothing more than either a dirty section on the pre-amp's volume dial or some electrical fault with the dial mechanism. I won't bore people with the description of how I have come to conclude this, unless they ask, but after a full day of listening I am confident of this.

Most likely time to get the pre-amp cleaned inside. Thanks and sorry for the somewhat banal posting.

:)

[MGFalc]

I'm glad you reported this as a few years ago, I had this very same problem and didn't figure it out for some time. It is as you say, that the contacts on the pot section of the volume control are dirty and that does not make a good contact thus leading to a 'scratching' sound heard through the speakers. I especially found this at low volumes which was due to the pot dragging the dirt back to the start point. WD40 does the trick or indeed any non-corrosive cleaner, although remember unplug when you spray! :)

[Mr Peabody]

Two things, first, I would not use WD-40 on electronics. It's an oil and will attract more dirt and gunk. Radio Shack should have what you need in a proper cleaner.

I don't see how it could be a dirty volume control if it didn't show symptoms before adding the power amp. It would have to be a big coincidence. It would also start out as a small problem and get worse. I'm not saying it has to be the amp but it was something with that transition. Maybe bad cables. It could even be a bad RCA jack on the integrated that showed itself after the plugging and unplugging.

No question is stupid.

[The Grudge]

Hi again. Yes it is actually the volume control being dirty. It appears that the dirt collects in little used areas such as very low volume setting. Due to the integrated being a little low in power I rarely listened to it on the lowest settings, I needed to adjust the gain higher constantly. Once the power amp was added I was of course leaving the gain on much lower settings on the pre. This brought the dirt into play.

I had always had some crackle when tutning the gain up and down before and it was getting worse. I will have to take it in for cleaning and I will make sure they do not use WD40, thanks for the warning! The power amp appears to be performing perfectly. I have been testing it and the problem seems completely limited to the gain control. I have to get use to thinking of the volume as gain! Thanks.

:)

[The Grudge]

Hi again, I wanted to update this old thread. The trouble mentioned is indeed the 2600A power amp I purchased from ebay! I have it in a shop I trust, but I do worry that they may skimp and use cheaper parts than the originals. I would like to understand what could be causing the problem better so that I could then understand what parts would need to be serviced or replaced.

When I discussed the problem with the technician he felt it was a wave issue and as I had to run I didn't get him to explain further. Does an amplifier use different sections to generate different levels of power? I don't know how to ask the last question differently, but the problems seem to disappear as I play the amp louder so it seems only low to mid power outputs exhibit the sound problems. Does that make sense? If so is there anything you can tell me to help me understand what is actually happening with the amp? Thanks again to any and all who do have some thoughts, much appreciated.

:)

[janderson7]

Hi again, I wanted to update this old thread. The trouble mentioned is indeed the 2600A power amp I purchased from ebay! I have it in a shop I trust, but I do worry that they may skimp and use cheaper parts than the originals. I would like to understand what could be causing the problem better so that I could then understand what parts would need to be serviced or replaced.

When I discussed the problem with the technician he felt it was a wave issue and as I had to run I didn't get him to explain further. Does an amplifier use different sections to generate different levels of power? I don't know how to ask the last question differently, but the problems seem to disappear as I play the amp louder so it seems only low to mid power outputs exhibit the sound problems. Does that make sense? If so is there anything you can tell me to help me understand what is actually happening with the amp? Thanks again to any and all who do have some thoughts, much appreciated.

:) I am having the same problem with my 2600A. distortion at low volume, intermitant. What did the repair shop find? did you get a satisfactory repair?

I'd love to hear your solution.