Forming new 700B power supply caps?
- Thread starter BMWR75
- Start date
Joe,
I was poking around my VOM probe at those two black wires that are normally connected to the lower cap negative terminal. When I separate the two black wire terminal connectors, the relays click in the DC protection board. At least one of these two connectors was touching the amp chassis when the spark/smoke event occurred. Does this mean anything?
Scott
I was poking around my VOM probe at those two black wires that are normally connected to the lower cap negative terminal. When I separate the two black wire terminal connectors, the relays click in the DC protection board. At least one of these two connectors was touching the amp chassis when the spark/smoke event occurred. Does this mean anything?
Scott
The second photo in the post below shows the B+ terminal only has the green jumper wire connected to it. The two red wire B+ connections are hanging out in open space.
As I was bringing the new caps up on the variac, the spark/smoke event occurred at I am guessing 20-30 volts AC. When I finally brought it up to full VAC, do remember the DC protect relays clicking cause it made me jump (wasn't expecting that).
EDIT -- just wanted to add that whatever weirdness went on with the WO board while forming the new caps was a freaky thing. I appreciate all the help you guys, especially Lee and Joe, offer up to knuckleheads like me.
As I was bringing the new caps up on the variac, the spark/smoke event occurred at I am guessing 20-30 volts AC. When I finally brought it up to full VAC, do remember the DC protect relays clicking cause it made me jump (wasn't expecting that).
EDIT -- just wanted to add that whatever weirdness went on with the WO board while forming the new caps was a freaky thing. I appreciate all the help you guys, especially Lee and Joe, offer up to knuckleheads like me.
Last edited:
New PS caps are hooked up to amp. Got a good dim bulb. Whew!! So far, so good.
Plugged the amp into a 120V outlet. Bias is 383 on left and 381 on right, maybe a few millivolts higher than when I checked months ago. DC offset is -10.1 mV on left and -11.3 mV on right.
I'm amazed so far. Was not expecting to get good results after I heard a spark and saw a whiff of smoke near the WO board while forming the new caps.
Guess it is time to hook up the bench speakers and a source and see what happens.
EDIT -- amp is playing beautifully!! I swear I heard and arc and saw smoke a few days ago. Must have been a bug getting zapped by flying in too close proximity to a WO board that is not supposed to even have power on it.
Plugged the amp into a 120V outlet. Bias is 383 on left and 381 on right, maybe a few millivolts higher than when I checked months ago. DC offset is -10.1 mV on left and -11.3 mV on right.
I'm amazed so far. Was not expecting to get good results after I heard a spark and saw a whiff of smoke near the WO board while forming the new caps.
Guess it is time to hook up the bench speakers and a source and see what happens.
EDIT -- amp is playing beautifully!! I swear I heard and arc and saw smoke a few days ago. Must have been a bug getting zapped by flying in too close proximity to a WO board that is not supposed to even have power on it.
Last edited:
Glad to hear that your amp lives!!!
I put in the new PS caps in my WOPL 1000's yesterday and they sound punchier, generally healthier. Both my amps are delivering over 216 vdc when measured at the filter caps...There is a wider soundstage, and drums sound amazing. Everything really pops; cymbals are crisper and vocals are silky smooth. Nice. When you think about it, it makes perfect sense. A power amplifier has one basic job; to regulate a power supply and drive loudspeakers with an output current proportional to the input. Sooo, the first requirement is to build a power supply for the amp to control, and those caps provide the source for instantaneous current. The better the source, the better the output...
I put in the new PS caps in my WOPL 1000's yesterday and they sound punchier, generally healthier. Both my amps are delivering over 216 vdc when measured at the filter caps...There is a wider soundstage, and drums sound amazing. Everything really pops; cymbals are crisper and vocals are silky smooth. Nice. When you think about it, it makes perfect sense. A power amplifier has one basic job; to regulate a power supply and drive loudspeakers with an output current proportional to the input. Sooo, the first requirement is to build a power supply for the amp to control, and those caps provide the source for instantaneous current. The better the source, the better the output...
I moved the WO 700 B into a nicer system today. AudioSmile modded DEQ2496 DAC, Rogue Audio Perseus preamp and KEF LS50 speakers. I really couldn't tell any difference before and after the PS recap. However, LS50s are not bass strong, they are small bookshelf size speakers. I mainly changed out the PS caps for long-term reliability and any improved bass response is a plus on full range speakers. Have some new 14" stands coming to use with a pair of JBL Synthesis Array 800s, will give the WO 700 B a road test when these are rotated into this system.
- Joined
- Jun 11, 2010
- Messages
- 6,867
- Location
- Powhatan, Virginia, United States
- Tagline
- WassupYa Mang?
- Joined
- Jan 14, 2011
- Messages
- 75,287
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
I romp on those 22K 100 volters like I stole em and aint popped one yet. I'll still use em for my own projects and some local work...I first started using those 22K 100 volters in 400's years ago, depending on the vintage I would have to make spacers for the faceplate to chassis connection....ah...those were the days...