2nd 100v Amp blown :( Help needed to troubleshoot.

Morning I've received the new amp and got things hooked up and am back in business! So thank you all very much for the help.

One issue is that.. I wired up the volume control that I swapped round to the room with 3 speakers incorrectly :( Attached is how it is currently wired and what I believe is correct? Previously I have the last two wires swapped around. My question is.. Have I damaged this volume control and need to replace or is it still wired incorrectly?

Many thanks,

Devs.
IMG_4048.JPG
 
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Okay I’ve been round the controls and checked for any stray wires and metered the outs. I’ve also swapped the more powerful control to the 3 speaker location.



The readings are as follows:



1 - Kitchen / Dining room - 3 x speakers / one twist vol. control - Reading = 1.21


2 - Downstairs Hall - 1 x speaker / one twist vol. control - Reading = 3.51


3 - Living Room - 1 x speaker / one twist vol. control - Reading = .359 (meter set to 2k)


4 - Upstairs Landing - 1 x speaker / one twist vol. control - Reading = .359 (meter set to 2k)


5 - Master Bed / ensuite 2 x speakers / one twist vol. control - Reading = 181.5



I’m hoping the new amp will land today so should be in a position to do further tests soon..



Do I still need to do anything with the 100w bulb?
Those resistance readings are a tad inconsistent. The reading on the master bed (with 2 speakers) should in theory be about half the reading for the upstairs landing.

I know there are issues with metering transformers using DC. I'm really intrigued by the reading on 1-4, they look too high for a transformer and too low for 8 ohm speakers. Your original amp wanted a minimum system impedance of about 50 ohms (which sounds right- at 50 ohms the total current would be 2 amps).

Just had another look at the pic of the speaker- can you remember what wires are in which hole in the terminal block? The BLUE coming in should connect to BLACK speaker, the BROWN coming in should connect to RED or YELLOW (speaker). From that pic it looks as if the RED and YELLOW might be connected to BROWN, which wouldn't be good.

We still haven't got to the bottom of why you've lost 2 amplifiers- you might want to try some current measurements (using the AMPS setting on your new meter). The lightbulb will act as quite a useful fuse but will also reduce the overall useful system output (since it'll be converting a good chunk of your audio signal into light and heat)

Have you measured the resistance presented to the amplifier yet? I don't think you'll get a realistic number but it should be greater than zero. You could also try some tone and volt experiments. With amplifier powered up but NOT connected to speakers, find a test tone on your replay device, play it, adjust input controls etc til the amp appears to be doing something and check the voltage at the 100v terminals (on the back of the amp) (Reason for tone= you should get a fairly constant voltage).
 
Those resistance readings are a tad inconsistent. The reading on the master bed (with 2 speakers) should in theory be about half the reading for the upstairs landing. I make the difference 4, is that something that would cause concern?



I know there are issues with metering transformers using DC. I'm really intrigued by the reading on 1-4, they look too high for a transformer and too low for 8 ohm speakers. Your original amp wanted a minimum system impedance of about 50 ohms (which sounds right- at 50 ohms the total current would be 2 amps). What could likely be causing these readings?



Just had another look at the pic of the speaker- can you remember what wires are in which hole in the terminal block? The BLUE coming in should connect to BLACK speaker, the BROWN coming in should connect to RED or YELLOW (speaker). From that pic it looks as if the RED and YELLOW might be connected to BROWN, which wouldn't be good. I’ve just had another look at that speaker and the wires are correct thankfully.



We still haven't got to the bottom of why you've lost 2 amplifiers- you might want to try some current measurements (using the AMPS setting on your new meter). The lightbulb will act as quite a useful fuse but will also reduce the overall useful system output (since it'll be converting a good chunk of your audio signal into light and heat). Im sorry but would you mind explaining this and the below process for me. As I do not understand what I need to do.



Have you measured the resistance presented to the amplifier yet? I don't think you'll get a realistic number but it should be greater than zero. You could also try some tone and volt experiments. With amplifier powered up but NOT connected to speakers, find a test tone on your replay device, play it, adjust input controls etc til the amp appears to be doing something and check the voltage at the 100v terminals (on the back of the amp) (Reason for tone= you should get a fairly constant voltage).



Many thanks as always,


Devs.


P.S just going back to the non functioning volume control that I moved into the kitchen. Should I be seeking to replace this? Am I likely to have blown it?
 
Those resistance readings are a tad inconsistent. The reading on the master bed (with 2 speakers) should in theory be about half the reading for the upstairs landing. I make the difference 4, is that something that would cause concern? Well your numbers on the post were master bed 181.5, upstairs landing .359, so a difference of 181.2!. It is intriguing- always dicey using DC for transformer impedance but some consistency would be reassuring.



I know there are issues with metering transformers using DC. I'm really intrigued by the reading on 1-4, they look too high for a transformer and too low for 8 ohm speakers. Your original amp wanted a minimum system impedance of about 50 ohms (which sounds right- at 50 ohms the total current would be 2 amps). What could likely be causing these readings? Dunno



Just had another look at the pic of the speaker- can you remember what wires are in which hole in the terminal block? The BLUE coming in should connect to BLACK speaker, the BROWN coming in should connect to RED or YELLOW (speaker). From that pic it looks as if the RED and YELLOW might be connected to BROWN, which wouldn't be good. I’ve just had another look at that speaker and the wires are correct thankfully. Good, as long as red OR yellow are connected then that's not the problem



We still haven't got to the bottom of why you've lost 2 amplifiers- you might want to try some current measurements (using the AMPS setting on your new meter). The lightbulb will act as quite a useful fuse but will also reduce the overall useful system output (since it'll be converting a good chunk of your audio signal into light and heat). Im sorry but would you mind explaining this and the below process for me. As I do not understand what I need to do. I suspect the impedance on your system is lower than the amplifier requires, causing the circuit to be carrying more current than the amp is rated for. Those meter readings you've done tell me there are no short circuits between the volume controls and the loudspeakers but the inconsistent readings are troubling. The light bulb (in series with the system) will guarantee that the total system impedance exceeds the minimum required and thus limits the current to below what the amp is rated for. It will make the system quieter though since it will be converting up to 100 watts into light and heat (instead of into sound).



Have you measured the resistance presented to the amplifier yet? I don't think you'll get a realistic number but it should be greater than zero. You could also try some tone and volt experiments. With amplifier powered up but NOT connected to speakers, find a test tone on your replay device, play it, adjust input controls etc til the amp appears to be doing something and check the voltage at the 100v terminals (on the back of the amp) (Reason for tone= you should get a fairly constant voltage).

OK, you have working amplifier- excellent. We'll skip voltage and go for current measuring instead
  • Have a look at the instructions (with your meter) for measuring current (you usually need to swap the LIVE probe from V/ohms hole to the 10A hole).
  • Switch the amplifier off
  • Disconnect the '100v' output from the amplifier (brown cable(s))
  • Connect the COM (black) probe to the 100v output on the amplifier
  • Connect the 10A (red) probe to the brown speaker cable(s)
  • Switch the amplifier back on
  • Find a test tone on Spotify or in any half decent audio program- play it through your speakers at a audible but not deafening level
  • See how much current is running
  • Turn the level of your test tone up till the speakers are delivering what you reckon is the loudest you'll ever want the things
  • See how much current is running
With your setup you should be running at 1 amp maximum (you've only got 10 speakers at 6W apiece). If it is a bit higher don't worry. If it is a lot higher there's still a problem, wire the 100w light bulb in series with the speakers and repeat the above tests.


Many thanks as always,


Devs.


P.S just going back to the non functioning volume control that I moved into the kitchen. Should I be seeking to replace this? Am I likely to have blown it?
You say you wired it up wrong- what did you do exactly?
 
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Good morning mate!


Those resistance readings are a tad inconsistent. The reading on the master bed (with 2 speakers) should in theory be about half the reading for the upstairs landing. I make the difference 4, is that something that would cause concern? Well your numbers on the post were master bed 181.5, upstairs landing .359, so a difference of 181.2!. It is intriguing- always dicey using DC for transformer impedance but some consistency would be reassuring. Sorry I think I’ve confused things here. for the one speaker I changed the meter setting to 2k as I wasn’t seeing a reading when set to 200. I’ll remeter the master bed.


We still haven't got to the bottom of why you've lost 2 amplifiers- you might want to try some current measurements (using the AMPS setting on your new meter). The lightbulb will act as quite a useful fuse but will also reduce the overall useful system output (since it'll be converting a good chunk of your audio signal into light and heat). Im sorry but would you mind explaining this and the below process for me. As I do not understand what I need to do. I suspect the impedance on your system is lower than the amplifier requires, causing the circuit to be carrying more current than the amp is rated for. Those meter readings you've done tell me there are no short circuits between the volume controls and the loudspeakers but the inconsistent readings are troubling. The light bulb (in series with the system) will guarantee that the total system impedance exceeds the minimum required and thus limits the current to below what the amp is rated for. It will make the system quieter though since it will be converting up to 100 watts into light and heat (instead of into sound). Okay thanks, let me double check that meter reading.


Have you measured the resistance presented to the amplifier yet? I don't think you'll get a realistic number but it should be greater than zero. You could also try some tone and volt experiments. With amplifier powered up but NOT connected to speakers, find a test tone on your replay device, play it, adjust input controls etc til the amp appears to be doing something and check the voltage at the 100v terminals (on the back of the amp) (Reason for tone= you should get a fairly constant voltage).


OK, you have working amplifier- excellent. We'll skip voltage and go for current measuring instead

  • Have a look at the instructions (with your meter) for measuring current (you usually need to swap the LIVE probe from V/ohms hole to the 10A hole).
  • Switch the amplifier off
  • Disconnect the '100v' output from the amplifier (brown cable(s))
  • Connect the COM (black) probe to the 100v output on the amplifier
  • Connect the 10A (red) probe to the brown speaker cable(s)
  • Switch the amplifier back on
  • Find a test tone on Spotify or in any half decent audio program- play it through your speakers at a audible but not deafening level
  • See how much current is running
  • Turn the level of your test tone up till the speakers are delivering what you reckon is the loudest you'll ever want the things
  • See how much current is running
With your setup you should be running at 1 amp maximum (you've only got 10 speakers at 6W apiece). If it is a bit higher don't worry. If it is a lot higher there's still a problem, wire the 100w light bulb in series with the speakers and repeat the above tests. Perfect, thanks for explanation, I understand and will check later.


With regards to my sloppy wiring.. (I currently have no sound in the 3 speaker kitchen area.) I wired the controller:


Out - Brown

Com - Blue


In - Blue

Com - Brown


I assumed this was incorrect and changed to (photo above):


Out - Brown

Com - Blue


In - Brown

Com - Blue



However I’m still not receiving anything to those speakers. :(

I just wanted to let you know that I’m out all day today but will have my phone. Will carry out some test later :)
 
Last edited:
Hi there, I'm now back in the house and have re metered and the following reading are correct with the meter set to 2k. I just wanted to run this by you before carrying out any further test incase it has a knock on.

4 - Upstairs Landing - 1 x speaker / one twist vol. control - Reading = .359 (meter set to 2k)


5 - Master Bed / ensuite 2 x speakers / one twist vol. control - Reading = 181.5
 
I've just tried the following test but unfortunately am not getting a read or an output from the speakers..?

  • Have a look at the instructions (with your meter) for measuring current (you usually need to swap the LIVE probe from V/ohms hole to the 10A hole).
  • Switch the amplifier off
  • Disconnect the '100v' output from the amplifier (brown cable(s))
  • Connect the COM (black) probe to the 100v output on the amplifier
  • Connect the 10A (red) probe to the brown speaker cable(s)
  • Switch the amplifier back on
  • Find a test tone on Spotify or in any half decent audio program- play it through your speakers at a audible but not deafening level
  • See how much current is running
  • Turn the level of your test tone up till the speakers are delivering what you reckon is the loudest you'll ever want the things
  • See how much current is running
 
Evening I did indeed, see attached. I grouped the browns for the test. Is this correct?
IMG_4062.JPG
 
All good EXCEPT the COM probe from the meter needs to be on the 100v terminal of the amp (to complete the circuit), not the COM terminal of the amp :)
 
Ha, standard chimp error! I've done that now and am getting the test tones but no meter reading :(
 
Well that's good news. Try winding the thing up to as loud as you ever have it on all the speakers that work- if the meter still doesn't register then either my methodology is flawed or current draw is very low (<200 mA by the look of that meter)
 
I've done the test again with things cranked up and am getting good sound from the speakers but no meter reading?

What are your thoughts on the 3 speakers in the kitchen, is it likely to be the controller thats failed?

Thanks, Devs ;)
 
Interesting (re the meter not showing any current). Have a read of the instructions, see if there's an internal fuse for the 10A bit, make sure it is in place and intact.
Check your meter instructions, see what it says about measuring up to 200 mA- set it up for that but start out at a low level (200 mA will be the amp delivering 20w so not very loud)
Kitchen speakers- could be the controller but unlikely, looks like passive components only and you've got a limited number of ways to foul up. Way to check is bypass the controller, (so connect blue to blue and brown to brown) and again start at a low level & see what happens (ideally set system to a low level then connect the kitchen speakers while system is operating and listen for any marked dip in output from the rest of it) BEING CAREFUL NOT TO SHORT THE OUTPUT LEADS TOGETHER (so connect BLUE to BLUE now, leave speaker BROWN floating and prod it in the AMP brown when you try it
 
There were no instructions with the meter unfortunately. It was a cheap thing off amazon, I've asked the question on there and will double check the setup.

I bypassed the controller and the 3 speakers in the kitchen didn't sound :( Trust that means that I've damaged them? Of all the zones :(
 

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