DCP going south??

[roccus]

I put a DCP in my WOPL 400 I was a bit hesitant to as the experience I have had with them in Pioneer amps has not been good every time I would crank an old Pioneer the relay kicks in and that is not a nice thing. I went ahaed and put the DCP im my PL to see how it would go. Well it had worked great for near a month since I finished the build and was ok with it till yesterday... I was cranking it when the relay cut out so had to power the amp down to reset relay... well it has happened again twice today does not do it a lower volume levels but if I crank it it shuts down.... any ideas?

 

[Lazarus Short]

DC protection? I'm going to throw out a guess - you need a DCP with a higher rating for current and/or voltage.

 

[NavLinear]

DC protection? I'm going to throw out a guess - you need a DCP with a higher rating for current and/or voltage.

The DC protect board is designed to accept the voltage level and current for the 400 so that's not an issue. If this has the Phoenix connectors I'd make sure that the connections are secure before doing anything else.

The circuit can trigger with very low frequencies due to the slope of the sine wave so it's possible, but not likely, that this is an issue. Another thought - a stressed relay may be at fault.

 

[roccus]

DC protection? I'm going to throw out a guess - you need a DCP with a higher rating for current and/or voltage.

Hmmm it's one Dons set ups... I think they have been pretty well tested as to if they are to weak to run on a WOPL... I'm thinking Dons DCP are a very good design for the very reason there are many of them out there running with no problems so I'm not sure if I have a problem going with the relay itself or something bad starting to go with the amp sending nasty current to the outputs but it just shut down again and only at moderate volume so what ever it is may be getting worse

Also want to mention I run a fan at all times when amp us in and when the speakers cut out I can see the meters still swinging away.....

 

[NavLinear]

Hmmm it's one Dons set ups... I think they have been pretty well tested as to if they are to weak to run on a WOPL... I'm thinking Dons DCP are a very good design for the very reason there are many of them out there running with no problems so I'm not sure if I have a problem going with the relay itself or something bad starting to go with the amp sending nasty current to the outputs but it just shut down again and only at moderate volume so what ever it is may be getting worse

Also want to mention I run a fan at all times when amp us in and when the speakers cut out I can see the meters still swinging away.....

The DC protect board opens the output from the amplifier to the speakers and has no effect on the rest of the amplifier.

 

[roccus]

The DC protect board is designed to accept the voltage level and current for the 400 so that's not an issue. If this has the Phoenix connectors I'd make sure that the connections are secure before doing anything else.

The circuit can trigger with very low frequencies due to the slope of the sine wave so it's possible, but not likely, that this is an issue. Another thought - a stressed relay may be at fault.

Hello Dennis thanks for your input here... I do have phoenix connections... they were soldered in real good and I tightened the screws as much as I dared without breaking something... I will go over the screws again just to eliminate that.... "a stressed relay" the one on the DCP what is that and is there a way to test that to find out??

 

[roccus]

The DC protect board opens the output from the amplifier to the speakers and has no effect on the rest of the amplifier.

Yes I just mentioned the fan and meters so you all would know it's not the thermal switch

 

[grapplesaw]

Do both channels drop or just one? If both drop is it at the exact same time? Did you put the board components on or was it obtained as a finished unit? Knowing these things will help with figuring out the problem

 

[roccus]

Do both channels drop or just one? If both drop is it at the exact same time? Did you put the board components on or was it obtained as a finished unit? Knowing these things will help with figuring out the problem

Yes both channels drop output at the same time they just goes dead , the board came all assembled I had to remove a couple caps cause I have WOPL backplanes. It was running great for the past few weeks at full tilt as well as lower volumes and I run it every day for 10 to 12 hours...

 

[roccus]

Another observation... I know the meters are not accurate but just using as a reference point when it is running where the meters average about -10 peak it will play all day no problems but when you get to where the meters are showing average peak at -4 where and occasionally jump into red the DCP cuts out within a few minutes

 

[moewillis]

just for curiosity sake... do you have any resistors in r7 and r8 left and right? it doesnt look like it in the picture and im pulling my hair out looking for mine. im about 75% done populating my board and cant find them anywhere. i was just going to email joe and ask but maybe you know?

 

[grapplesaw]

This is from Don's manual
The circuit is based on the UPC1237 IC that is intended for this application. Essentially it is avoltage monitor that engages the relay. The voltage monitor must be able to discriminatebetween very low bass signals and DC. A timing capacitor allows the voltage monitor to ignorethe low bass but will quickly release the relay if DC is present




If you start clipping the unit you create DC through the the top and bottom of the clipping sine wave.
It looks like the unit is performing admiralty as it should
best to put it on a scope to check.

On on an other note the meters will work regardless of the DCP

 

[roccus]

just for curiosity sake... do you have any resistors in r7 and r8 left and right? it doesnt look like it in the picture and im pulling my hair out looking for mine. im about 75% done populating my board and cant find them anywhere. i was just going to email joe and ask but maybe you know?

I don't believe I do there are a few differences if you are using stock backplanes or wopl backplanes I built mine with the wopl backplanes... you putting those in yours as well?? Shoot us some pics everyone loves pics

 

[roccus]

This is from Don's manual
The circuit is based on the UPC1237 IC that is intended for this application. Essentially it is avoltage monitor that engages the relay. The voltage monitor must be able to discriminatebetween very low bass signals and DC. A timing capacitor allows the voltage monitor to ignorethe low bass but will quickly release the relay if DC is present




If you start clipping the unit you create DC through the the top and bottom of the clipping sine wave.
It looks like the unit is performing admiralty as it should
best to put it on a scope to check.

On on an other note the meters will work regardless of the DCP

I'm thinking something somewhere is not right as it was running fine even full tilt and from what I understand many who build these run them full tilt without a problem... What is best way to check it out? I have a scope

 

[NavLinear]

I'm thinking something somewhere is not right as it was running fine even full tilt and from what I understand many who build these run them full tilt without a problem... What is best way to check it out? I have a scope

Do you have the installation procedure? Here's an excerpt from Wattsabundent power up instructions that may help.

Power Up Method With Light Bulb Test Set (Preferred)

1. There should be no input or output cables connected. The light bulb test shown below is
highly recommended for initial testing. In the event that a mistake is made it will prevent
catastrophic failure. A variac doesn’t limit current and does not provide adequate protection.

2. To use the test set plug the amp into the “Amp Under Test†socket. Do not connect any
cables to the input/output jacks.

3. Verify the switch is in the center off position.

4. Plug a 100 watt bulb into the other socket.

5. Plug the test set into a standard 120V outlet.

6. Move the switch to the test position. The lamp should momentarily be very bright and
quickly dim in less than 3 seconds. If it does not dim stop. Do not go any further until the
problem is found.

7. Move the test set switch to off and then normal. The relay should click within 5 seconds.
If it doesn’t there is likely to be a wiring problem.

8. If a signal generator is available insert a 1KHZ sine wave into the left channel. Set the
generator level to obtain 40 VAC on the amplifier output.




NOTE: A computer sound card can act as a signal generator with widely available freeware.

9. Decrease the frequency until the relay clicks. This should be between 1.1Hz and 30 Hz.

10. Raise the frequency to 1KHZ. Turn power off and back on.

11. Repeat steps 8-10 for the right channel.

 

[roccus]

Ahh ok thanks I do remember reading this back when I got the board.... Joe had mentioned using a scope

Do you have the installation procedure? Here's an excerpt from Wattsabundent power up instructions that may help.

Power Up Method With Light Bulb Test Set (Preferred)

1. There should be no input or output cables connected. The light bulb test shown below is
highly recommended for initial testing. In the event that a mistake is made it will prevent
catastrophic failure. A variac doesn’t limit current and does not provide adequate protection.

2. To use the test set plug the amp into the “Amp Under Test†socket. Do not connect any
cables to the input/output jacks.

3. Verify the switch is in the center off position.

4. Plug a 100 watt bulb into the other socket.

5. Plug the test set into a standard 120V outlet.

6. Move the switch to the test position. The lamp should momentarily be very bright and
quickly dim in less than 3 seconds. If it does not dim stop. Do not go any further until the
problem is found.

7. Move the test set switch to off and then normal. The relay should click within 5 seconds.
If it doesn’t there is likely to be a wiring problem.

8. If a signal generator is available insert a 1KHZ sine wave into the left channel. Set the
generator level to obtain 40 VAC on the amplifier output.




NOTE: A computer sound card can act as a signal generator with widely available freeware.

9. Decrease the frequency until the relay clicks. This should be between 1.1Hz and 30 Hz.

10. Raise the frequency to 1KHZ. Turn power off and back on.

11. Repeat steps 8-10 for the right channel.

 

[roccus]

Just wondering.... is it possible for a preamp to send DC through the amp to the output??

 

[stuwee]

I'm not an expert but, I seriously doubt that can happen, preamps operate at a very low voltage, current comes from the amp, hence DC.

 

[NavLinear]

I'm not an expert but, I seriously doubt that can happen, preamps operate at a very low voltage, current comes from the amp, hence DC.

Current is not part of the dc protect issue. If the board senses a dc level, defined by Don as a frequency up to 30 Hz, than the dc protect board may be working fine and it is possible that the preamp is also working ok. IMO a calibration of the dc protect board characteristics should be done to better understand the problem. The protection circuit may be working ok but if it triggers on a low frequency such as 30 Hz then it may be necessary to change a discrete component to modify the threshold.

 

[roccus]

Thanks guys I will have a look see... thing that is puzzling me is why did it just start doing this now and not from day 1? I did not run the frequency test when I did the build I did the dmb with a veriac hookup.... as some of you who followed my build will recall I hooked up to the wrong leg of the rectifier but once I got it on the right side of it on power up the relay on the DCP would kick in at about 60V

Right now my C-1 preamp is also down I did what is called a BillD mod on it. The first stage of the mod is changing all the caps which I did and it worked out great I got good clean sound and it improved my bass response I was very please with the results I then decided to go onto stage 2 of the mod where you replace a few key opamps. The replacement opamps are surface mount so you need to get adapters called browndogs, these adapters have solder pads on top to mount the surface mount opamps to and the bottom of the adapters have have pins that align up perfectly with the original opamp pin holes on the PC board.

While I waited the 4 or 5 days for the new opamps to get here I was really enjoying the new amp and the C-1 everything was working perfect. When the opamps got here I out them in paying close attention to make sure I got pin 1 to go where pin 1 was supposed to go on both the surface mount opamps and then the adapters to the PC board. When I connected the C-1 to the 400 I was horrified as all I got was some static, popping, and squealing, the meters on the 400 were jumping all over the place something was really wrong with the adition of the new opamps.

I pulled the new opamps out and put the originals back in but still the same thing I must have blown something else in the C-1. I have been in contact with people over on the Carver forum about this issue they asked for pics of the new opamps mounted on the browndogs which I put up for them they agree I did build them right but mentioned there may be a problem with the new run of adapters. So I ended up connecting the pioneer SX 939 back to the 400 for the preamp as I was using it before I got the C-1. But this problem with the relay started after I had connected the screwed up C-1 to the amp and is why I was wondering if the preamp could send a DC voltage through the amp.

So now I am sitting here with my C-1 down and my amp going down it sucks to be me right now after all my hard work and investment to be where I am now.. lesson here quit while your ahead if I had stopped after the stage one mod on the C-1 everything would probably be good now but I stuck my neck out and went for it all now it is costing me