Phase Linear 4000 Pre Amplifier - Volume stuck at a high level

[hawkeyesound]

I have a Phase Linear 4000 Pre Amp and a Phase Linear 400 Amp. I had these setup, along with a Bose Equalizer, and was getting great sound from them (when hooked up to a CD player for the component).

I moved these to a different location (in the same room) and when I hooked them up again the volume would not adjust and it remains at a very high level.

I was wondering if anyone has any experience dealing with this problem and might provide some suggestions on what needs to be done to fix it.

(I am not savvy when it comes to repairing these components. These were actually gifted to me by a family member.)

 

[TimD]

Check the ground lead on the volume control, and also (first) confirm that you are plugged into the correct output. If you missed and hit a record out, fx loop out, etc. it would not have volume control by design.

I'm betting a miswire after the move . . .

 

[mlucitt]

You have come to the right place, we will get this sorted out even if you have to completely disassemble and then reassemble your PL4000 preamplifier and PL400 amplifier. Don't worry, it will be great!

 

[marcok]

Already seen in one of my two PL 4000 . Simply deox the pot connector .
Ciao e benvenuto
Marco

 

[hawkeyesound]

Thanks for the info everyone. I am a complete newbie to this, so it may take a few trial and error runs before I figure this all out.

 

[hawkeyesound]

Check the ground lead on the volume control, and also (first) confirm that you are plugged into the correct output. If you missed and hit a record out, fx loop out, etc. it would not have volume control by design.

I'm betting a miswire after the move . . .

On the output from the Pre Amp, I had been using the Tape 2 ports, going out to the Equalizer. Does that sound like the correct path?

 

[TimD]

Tape ports have *ZERO* volume control - they are intended to provide a fixed level to a tape deck. The only volume controlled front output on the 4000 is (as per the maual) Main L and R. Considering that there is no insert loop capability on a 4000, you need to go fro Mail L and R to the EQ, and then the EQ to the amp.

Download Phase Linear 4000 Series Service Manual | ManualsLib

www.manualslib.com

 

[hawkeyesound]

Tape ports have *ZERO* volume control - they are intended to provide a fixed level to a tape deck. The only volume controlled front output on the 4000 is (as per the maual) Main L and R. Considering that there is no insert loop capability on a 4000, you need to go fro Mail L and R to the EQ, and then the EQ to the amp.

Download Phase Linear 4000 Series Service Manual | ManualsLib

www.manualslib.com

Thanks for confirming.

 

[hawkeyesound]

Already seen in one of my two PL 4000 . Simply deox the pot connector .
Ciao e benvenuto
Marco

Deox the pot....no change yet.

 

[TimD]

Thanks for confirming.

I confirmed that what you said you are doing is *WRONG*! Use Main L and R!

 

[Ronnie_B]

I confirmed that what you said you are doing is *WRONG*! Use Main L and R!

Confirming this. You need to use the main L & R outputs if you want the 4000 preamp volume control in the circuit.