Problems with Parasound AVC 1800

I've bought an used AVC1800. Diring DD/DTS playback there is
a buzzing (not ground AC)sound from all channels except the center that is noticeable on 0dB and over volume.
Parasound sent me a new DSP card. It did not solve the problem. There are also some pops between tracks with the CD
playback. Does anybody have the same problems?
I'm going to ship the unit to Parasound for service.
Ship it.Its under warranty and they pay for return shipping.I bought mine used here and during shipping solder broke loose from Toridial transformer.[cracked the board].They fixed problem and upgraded chip[without me asking].I told them I bought it used also.GREAT SERVICE from Parasound!!Turnaround time 7 days!Cal to Wisc.Returned it in a factory box too which I didn't have.I'm Happy and Its a great unit.
Have you ever tried adjusting your digital input levels ? While i don't think that this is your main problem, it might be worth a try.

I too had to crank the tar out of the volume control to get good levels out of my HT system. Between that and the very slow speed that the volume ramps up or down at, i decided to sell mine. For the money, i think that it was the best processor that i had tried. Too bad it didn't have a phono section or analogue pass through. Then again, you can get these things for "peanuts" now, so you can't really knock them. Sean
If noise is coming from your unit send it back. it is probaly the loose solder. This is a known problem with some of thier products. I have many and after they said it could be a ground loop problem they discovered the solder broke off. I have their seperate 1500 pre/pro system with 3 1000a tuner etc. Their customer service is great!! If your unit is slow to volume change remotes.It is not the product. their version of remotes are poor.
I have received an exchange unit from Parasound and it still all the same. If I can live with poppings between CD tracks (some more expensive AV controllers do the same), but the digital noise from the front channels during DD/DTS playback is unbearable for me. Is this problem common for all AVC 1800 or there is something wrong with my setup?
Mine is dead quiet.
Eugene, are you feeding the AVC 1800 the signal from your CD / DVD player via a digital coaxial cable ? Sean
Yes, Sean.
I use a digital coax since my old Toshiba DVD player has only a coax output. I've just received the second unit from
Parasound and it is still the same. It is a distinct digital sound from front/surround speakers during DD/DTS playback at the volume level close to 0 dB and higher.
Okay, now we may be getting somewhere. Thanks for the update.

As to the noise between tracks, that probably has to do with the Para's internal DAC's shutting off and turning back on. Some cd / dvd players actually turn off the digital output when no signal is present. This causes the DAC to go out of lock or temporarily shut down. When the next cut starts up, the digital datastream is re-energized causing the DAC to switch back on.

The "cure" for this is to have the Para modified so that the DAC's don't shut off. I know that this can be done as i and many others ran into this problem when CAL went to their 24/96 versions of the Alpha and Sigma. All you had to do was to disable a transistor ( probably being used as an electronic switch ) and there was no more "clicking".

Another solution to that would be to change the digital transport that you are using to something that outputs a continual digital stream. This would allow the Para's DAC to remain in lock. I don't know if you would run into this problem when running optical, but that is a moot point since your current DVD doesnt' offer that type of jack anyhow.

As to the "digital noise" that becomes apparent as listening levels are cranked, have you ever adjusted the digital input trimmer ? I ran into something similar with my 1800 when i had it and i had to knock down the drive level coming into the processor from the DVD player to correct it. While this wasn't a problem on every disc, it was quite apparent on some that were recorded a little hotter than most. The higher recording level resulted in higher output levels from the transport which drove the DAC's into digital clipping. You should be able to find info in your Para manual about how to correct this problem if you already haven't looked into this. Why this would be apparent at higher volumes as compared to lower volumes simply has to do with the fact that you can more easily hear the noise / distortion that it is generating.

These are both just guesses, but i hope that they might at least point you in a direction that goes somewhere... Sean
Thanks for the detailed response, Sean. I still have two questions.
How to trim the digital input? According to AVC-1800 manual there is only the analog input level adjustment. I’ve tried to use it for the digital and it did not work. There are temporary trimmings
for individual channels. Is that what you mean?
How to disable a transistor? Is it on the DSP card? I am not a stranger to fix boards down to the component level.