• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Yamaha MSP7 STUDIO speaker damaged after short 100% volume?

speakersuggestion

New Member
Joined
May 14, 2021
Messages
4
Likes
1
Hello,
yesterday I received my Topping D10 Balanced DAC and connected it to my Yamaha MSP7 STUDIO speakers using balanced cables. I ordered it to fix PC static noises I'd get when playing CSGO:ZE, DayZ and even from moving the mouse using my mainboard's audio, not for "Hi-Res" audio, 16bit/44110Hz is all I need. Before this DAC I had a Schiit Modi 2 DAC, where the PC noise was very quiet, but it has this issue and recently has stopped working at all. The PC noise with the Topping D10 Balanced is fortunately non-existent so far.

The speakers' volume is set to 3 clicks internally, so not very loud, but when I switched to the new DAC by clicking and selecting it in my Linux sound settings, the volume was set to 100% and of course the speakers became very loud. I quickly lowered the volume. A bit later I noticed that the left speaker is quieter than the right speaker, I guess by about 30-50%, and it's very notable. I tried switching the cables, disconnecting the other speaker, and even connected the previous unbalanced cable from my mainboard to the speakers, but even then the left speaker is quieter, which previously, I'm sure, was not the case. As the balanced cables are new, they should not be the issue, but I still measured them using a digital multimeter, and they seem fine. Maybe the speaker got damaged during that short 100% volume setting? Using an online tone generator site I tested for 50 Hz and 3000 Hz and both drivers seem equally quieter, so maybe the drivers are fine but the amp or something else got damaged? Anyone here with similar case? Searching around didn't reveal anything so far, but I wouldn't be surprised if it did. What should I do next, open the speaker and measure/compare the amp voltages to the other speaker?

Edit:
I measured the impedance of both drivers: HF: 5.3 ohm, LF 3.1 ohm. 3.1 ohm seems a bit low but IDK. The board also looked fine at first glance. To make sure the drivers aren't the issue, I will exchange the boards to see whether the drivers or something on the board is the issue.
 
Last edited:
OP
S

speakersuggestion

New Member
Joined
May 14, 2021
Messages
4
Likes
1
Can't edit the first post anymore.
The second speaker's drivers measure HF: 5.4 ohm, LF: 3.0 ohm. After exchanging the backside from left speaker to right speaker, the right speaker sounds quieter now (expected, after measuring the drivers' impedance), so it's definitely something on the backside (input,passive components,transformer,amplifier). After adjusting/balancing the speakers volume via software, I think the right speaker still lacks something, but I'm not sure. I re-checked the volume pot and the switches, they were/are equally set on both speakers. My biggest guess of what the issue could be is that there are multiple parts driving/amplifying both HF and LF drivers and part of them got damaged during that short 100% volume duration. I attached the MSP7 STUDIO Service Manual, maybe someone wants to take a look at it. I will see what I do next.
(I'm 100% sure that both volume pots were set equally to 3 clicks on both speakers when the 100% volume thing happened and that the volume difference is big now and that there was 0 difference before connecting the D10 Balanced DAC. Setting the left speaker's volume to 1 click and right speaker's to 2 clicks to try to equalize the volume makes the right speaker way louder and is another proof, if you will, that it certainly wasn't Yamaha's intention to have different volume click amounts and that both speakers' volume click number should make them sound equally loud.)
 

Attachments

  • yamaha_msp7.pdf
    2 MB · Views: 21

okok

Senior Member
Joined
Oct 31, 2020
Messages
331
Likes
123
poor baby, never use poor system like linux, unless you constumed your own code
 

DVDdoug

Major Contributor
Joined
May 27, 2021
Messages
1,495
Likes
1,908
It would be unusual to get a "simple" drop in volume. The woofer OR tweeter might get damaged or "blown, so you might get distortion in the highs or lows, or a complete loss of the highs or lows.

It would also be unusual for the electronics to be damaged by excessive volume.

I wouldn't expect a short-term "overload" to cause any problems. With an active speaker the amplifier power is "matched" to the drivers and it's usually heat that burns-out speakers, and it takes a moment for the voice-coil to heat-up/burn-up.
 

Holdt

Active Member
Joined
Jun 10, 2022
Messages
299
Likes
208
Well, you did the troubleshooting yourself. -Seems like the amplifier board got damaged.

What's "unusual" and "usual" in terms of the damage isn't of concern if it's beyond warranty. Electronics sometimes fail.
 
Last edited:
OP
S

speakersuggestion

New Member
Joined
May 14, 2021
Messages
4
Likes
1
In the meantime (which is some time ago by now) I did some more testing:

1. I exchanged the whole aluminum base parts between the speakers, which consists of "INPUT" + "AMP"(=PCB+"POWER AMP") + "TRANS" and then the right speaker got quieter, so it's definitely not the drivers, as was kinda expected.
2. Then I exchanged only the AMP + TRANS parts (they are connected by wires which can not be taken apart easily AFAICS) and the right speaker is still quieter, so it's definitely not the AMP+TRANS part but the INPUT.

Then I ordered some more measurement tool: DE-5000 LCR meter (without original probes), bought Hirschmann 2x(KLEPS30+CO MLN 50/2,5) (that makes it 2-wire measurement, not 4, indeed) probes+cables (the DE-5000 was able to calibrate using these and unable to calibrate using the known generic China "2x LCR Meter Low Resistance Clip Leads"). Ordered the TORX TR T20 to reach the INPUT PCB.

But now (also some time ago by now) the speaker seems to have repaired itself and if anything, the left speaker is like 10%? quieter now(?):
-- Maybe it's due to the mentioned AMP + TRANS exchange and each AMP+TRANS only fits certain drivers best?
-- And/or maybe it's due to that the left speaker stands on a speaker tripod and the right speaker stands on the original YAMAHA speaker cartons boxes?
-- Xor maybe it's also the speaker positioning?
But the volume difference is basically only noticeable if moving the balance toggle left and right quickly.

The difference of like 30-50% in volume before was huge and also not due to software as I exchanged the left and right cables of the DAC output (to make it more clear: cable A from DAC output left to output right, not the cables themself, of course) as mentioned before.
So, IDK, super strange. I'm glad it fixed itself :)
My biggest guesses are that due to warmer temps before, some proper contact was missing due to slight material expansion and aligned itself again now that the temps are cooler, but still needs to be fixed/soldered again? Or that some capacitor fixed its own internal resistance, but IDK if that is a thing.

@DVDdoug There was no distortion, but all frequencies seemed to have been equally affected.
@Holdt Yes I did more basic troubleshooting myself, but didn't look into the "INPUT" PCB part as the speaker seems to be alright again/fixed itself.
 

Cbdb2

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
844
Likes
780
Location
Vancouver
If you loose one side of a balanced input (the + or the - ) you usually still get a signal its just 6 db down. So the problem was somewhere around the inputs.
 
Top Bottom