Phase linear 700 b

V

v65magna

Journeyman
#1
Joined
May 6, 2019
Messages
69
#1
hi everyone hope everyone is well , my question is what the safe dc off set for the 700 b , a lot of forums on this say under 50mv is fine , seems when I turn up the out puts on the front panel the dc off set goes up a tiny bit , is this normal right channel was around 12.4 mv
Left was a lot lower , I’m going to order the dc protection board off eBay $119 but it says u have to find installation information off watts abbantt I search it and there are pics and instructions but not very detailed , would anyone know where a can get a diagram showing exactly where each wire goes that would help a lot , any help on the dc off set and a diagram showing where to hook up each wire would be much appreciated
 

Attachments

WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#3
Joined
Aug 10, 2015
Messages
11,227
Location
Minnie-Soda
Tagline
Screw it
#3
seems like all the noobs are getting lazy and not looking at the documentation available to EVERYBODY. They want shit handed to them instead of digging for the answers.
 
laatsch55

laatsch55

Administrator,
Staff member
#6
Joined
Jan 14, 2011
Messages
74,216
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#6
V65, last time I looked at watts' website there was adequate documentation to hook up to a stock 400/700. There was NOTadequate documentation for a White Oaked 400/700 for someone who had not installed one before. Check Don's site again and post your questions ..
 
laatsch55

laatsch55

Administrator,
Staff member
#7
Joined
Jan 14, 2011
Messages
74,216
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#7
On the PL14-20 series of driver boards the offset can only be changed by new front differential pairs---Q1,Q2...
 
V

v65magna

Journeyman
#9
Joined
May 6, 2019
Messages
69
#9
laatsch55 said:
12mv in a stock 700B is not bad...
Click to expand...
ya thanks for your answer much appreciated , like i said the left is around 3.4 mv the right is 12.6 mv but like I said earlier when I turn the front out puts to max the right goes to 24.2 mv the left 4.2 mv they say to check with the out puts at min , I checked both ways thanks again my friend
 
mlucitt

mlucitt

Veteran and General Yakker
#10
Joined
Jun 24, 2011
Messages
3,367
Location
Jacksonville, FL
#10
v65magna said:
ya thanks for your answer much appreciated , like i said the left is around 3.4 mv the right is 12.6 mv but like I said earlier when I turn the front out puts to max the right goes to 24.2 mv the left 4.2 mv they say to check with the out puts at min , I checked both ways thanks again my friend
Click to expand...
The DC Offset has to be checked with nothing connected to the inputs. In other words, no signal applied to the inputs.
With an input signal, transistors Q1 and Q2 (stock PL700B) or U1 (WOA Control Board) are conducting and you will not get a consistent quiescent DC Offset measurement.
Your stock PL700B DC offset is not bad at all, as Lee said.

Buy your DC Protect Relay Board. Watts Abundant is a regular contributor here, he can help you and we will chime in too.
 
Last edited:
V

v65magna

Journeyman
#12
Joined
May 6, 2019
Messages
69
#12
mlucitt said:
The DC Offset has to be checked with nothing connected to the inputs. In other words, no signal applied to the inputs.
With an input signal, transistors Q1 and Q2 (stock PL700B) or U1 (WOA Control Board) are conducting and you will not get a consistent quiescent DC Offset measurement.
Your stock PL700B DC offset is not bad at all, as Lee said.

Buy your DC Protect Relay Board. Watts Abundant is a regular contributor here, he can help you and we will chime in too.
Click to expand...
Thank u very much I appreciate u getting back to me I will buy the protection board from watts , and again thanks and stay safe
 
laatsch55

laatsch55

Administrator,
Staff member
#14
Joined
Jan 14, 2011
Messages
74,216
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#14
Are you adjusting the pot on a PL14 board??,? If you are you are adjusting BIAS!! And yes offset will change with bias settings....
 
laatsch55

laatsch55

Administrator,
Staff member
#15
Joined
Jan 14, 2011
Messages
74,216
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#15
V65, could you post a pic of the driver board?? And what do you mean " turn up the outputs"??
 
V

v65magna

Journeyman
#18
Joined
May 6, 2019
Messages
69
#18
laatsch55 said:
Ok, have you adjusted bias?
Click to expand...
No not yet , I’m waiting till I get the dc speaker protection board from watts abbantant , will adjusting the bias even out the dc off set or lower it , I seen some forums saying the 700b has no pots to unjust the offset thanks again for helping me out , I appreciate it big time
 
laatsch55

laatsch55

Administrator,
Staff member
#19
Joined
Jan 14, 2011
Messages
74,216
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#19
Correct, no offset adjustment on a 700B..adjusting bias is a wise thing to do if it hasn't been done yet. They can run way hot if not adjusted in range.
 
V

v65magna

Journeyman
#20
Joined
May 6, 2019
Messages
69
#20
v65magna said:
No not yet , I’m waiting till I get the dc speaker protection board from watts abbantant , will adjusting the bias even out the dc off set or lower it , I seen some forums saying the 700b has no pots to unjust the offset thanks again for helping me out , I appreciate it big time
Click to expand...
laatsch55 said:
Correct, no offset adjustment on a 700B..adjusting bias is a wise thing to do if it hasn't been done yet. They can run way hot if not adjusted in range.
Click to expand...
thanks a lot my friend I will try to unjust the bias when the board arrives , also would a inline fuse work till I get the board ,,as I made this dc off set protection box with 2 fast blow 3 amp fuses, but I never tryed it yet ,, I always used this amp with no dc protection for aleast 3 years never had a problem with it ,I always have a good fan blowing on those black cooling fins in the back , but I think it’s time I put in that Dc protection circuit , I’m always putting it off because I don’t want to do something wrong and screw something up when I do install the protection board,, I love this amp , I did hear it’s quite easy to install , thanks again answering my questions I really appreciated it , also when I get the board if I need assistance would help me out thank u stay safe my friend
 

Attachments

You must log in or register to reply here.
Top