Phase 400 rebuild

[Dchristie]

Out of all the amps I've done, I've only soldered one DCP board in. I thought it would look less cluttered with the wires coming up from the bottom and soldered on the top. It achieved that objective, but it was a pain in the ass. I've had no problems with the others.

This is good to know. I am attributing my issues to "operator error". Not the 1st time and I am sure it will not be the last.

 

[laatsch55]

It can happen, I mean we are stripping these babies to the bare chassis and running every wire, that's a lot of potential for a small mistake...

 

[Dchristie]

After more investigation, it appears that 2 of my older preamps ( Citation 11 and 17) are the only preamps that are in the chain when the dropouts occur. I have been using the WOPL400 for the past week with my Benchmark preamp/DAC with no problems whatsoever. Also had no problems using the WOPL 400 with a Marantz 3250B preamp.
So the speculation is that the preamps my be leaking some DC into the signal chain which is activating the DCP in the Phase 400.

So, my question to anyone is - how do you measure DC offset in a preamp ? My assumption is that you would measure the voltage between the positive and ground of each phono out jack ? Volume at minimum, all controls out of the circuit, and input set to aux ?



Thanks

Dean

 

[laatsch55]

Main out jacks, check with each input in line...

 

[laatsch55]

In other words, signal positive and ground shell on pre out on the meter leads, then check with the input selector on each different input.....

 

[Dchristie]

Thanks Lee ! I will check them out. But regardless, the amp is performing without any issues with my better preamp so I am pretty confident it is functioning as designed.

On another note, just waiting on a DCP board and a couple of other parts and Del (second WOPL400 rebuild - Del on the factory sticker for this amp) will also be up and running.

Thanks again

Dean

 

[laatsch55]

Welcome sir!!

 

[Dchristie]

Del and Pam

So, after embarking on this project over a month ago, I have finished my 2nd WOPL400 (Del). Also found out that the original DCP board for Pam was missing a cap so I used one of the caps from the WOPL conversion of Del's DCP board to supplement the missing cap on Pam's board. So, hopefully, everything is now good.


Anyways, here are the happy couple.

 

[WOPL Sniffer]

Nice work Dean.

 

[Gepetto]

Very nice...the units you converted look quite clean...you don't often get them with such nice cosmetics.

 

[Dchristie]

Thanks Joe - you know that this would have been a lot more difficult without your help and advice. The 2nd amp went much more quickly and smoothly ( as you indicted it would). Actually, if I hadn't mixed up those last 2 NPN/PNP transistors on amp 1, the whole project would have been without any major issues.

I spent way too much for the 2 amps just to get good cosmetics . And in reality the 2nd amp ( Del) has some major scratches around the finish bolts that do not show up in the pics. I have a 3rd PL400 with a very good face plate that I am going to switch out at some time.

Listening to Del as I type and he sounds great. Amazing bass ( even on the small bookshelves - Avid 100s) that I am using to test and also nice clarity. Nothing like a couple of hundred watts to open up the music.

Anyways, I am very satisfied and glad Navo ambushed me on AudioKarma.

 

[Gepetto]

Thanks Joe - you know that this would have been a lot more difficult without your help and advice. The 2nd amp went much more quickly and smoothly ( as you indicted it would). Actually, if I hadn't mixed up those last 2 NPN/PNP transistors on amp 1, the whole project would have been without any major issues.

I spent way too much for the 2 amps just to get good cosmetics . And in reality the 2nd amp ( Del) has some major scratches around the finish bolts that do not show up in the pics. I have a 3rd PL400 with a very good face plate that I am going to switch out at some time.

Listening to Del as I type and he sounds great. Amazing bass ( even on the small bookshelves - Avid 100s) that I am using to test and also nice clarity. Nothing like a couple of hundred watts to open up the music.

Anyways, I am very satisfied and glad Navo ambushed me on AudioKarma.

It must have been his photos that reeled you in...

Anyway, we are glad to have you on the forum Dean

 

[NavLinear]

Hey Dean - you did a damn good job upgrading your amps. From what you mentioned in AK I felt you had the skill set and you proved that you could do it!

There are a lot of good people here with a wealth of knowledge about Phase Linear so you came to the right place. One of the really cool aspects of this site is that Joe of White Oak fame spends a lot of time here. His designs have elevated the original Bob Carver designed amps to levels that rival amplifiers that cost many times of an upgraded Phase Linear amplifier.

Joe - I did post a couple of photos of my favorite nurse on AK in a thread about a nice looking McIntosh amplifier - something about drooling over the amp that forced me to post. Here she is for those that don't know:

 

[Northwinds]

Killer job Dean!!!

 

[Gepetto]

Hey Dean - you did a damn good job upgrading your amps. From what you mentioned in AK I felt you had the skill set and you proved that you could do it!

There are a lot of good people here with a wealth of knowledge about Phase Linear so you came to the right place. One of the really cool aspects of this site is that Joe of White Oak fame spends a lot of time here. His designs have elevated the original Bob Carver designed amps to levels that rival amplifiers that cost many times of an upgraded Phase Linear amplifier.

Joe - I did post a couple of photos of my favorite nurse on AK in a thread about a nice looking McIntosh amplifier - something about drooling over the amp that forced me to post. Here she is for those that don't know:

That is what reeled him in Dennis, for sure. Was at the hospital recently when my daughter delivered her first born son and I can tell you there were no nurses that looked like that!!

 

[Dchristie]

So where were you Dennis, when I screwed up the positions of the last 2 transistors on my 1st WOPL400?

That's when I could have really used a good NURSE!