Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Relative volume levels M1MkII and D600

I have just got my M1MkII speaker amplifiers repaired by Highview Video. New capacitors were needed.

I have been using D600 as main speakers while the M1 amps were repaired.

With the four speakers together to match volume the M1s on full volume from the 101B is only at 43 volume level on the D600. At a level of 55 the D600 are very loud and they go onto unbearably loud at over 60. The same signal is feed to the tuner input on the 101B controlling the M1 and directly to the D600 analogue input from a Terratec DMS6X fire USB external sound card.

The M1 have 100 Watt amplifiers, the D600 70 Watt. I don't or shouldn't want to run them so loud but it was always nice to know that the M1 would bounce the ceiling joists if I wanted them to; that mantle seems to be the domain of the D600 now.

Should the D600 be so much louder than the M1?

the M1/101 combo on its own should be producing earth shattering volume in a normal room at full volume, this suggests that the signal to the preamp is not fully driving the preamp, have you tried a standard analogue source? or a different input?or your 101 is not producing full output.

Rgds
Stuart

I have tried the 104 which shares the same input as that from the computer sound card.

I was expecting much higher volume levels.

I have not tried any other input. The speakers are balanced and I use the DIN cable input with two twisted wires. The speaker amps have RCA phono socket. Could I feed the signal from the FM104 and computer through that direct and not through the 101b?

Hi

What did it sound like prior to repair?

Regards I

One amp was popping at least every hour and has since I got the D600, even after a repair the popping soon returned. Then one amp was dead and so I sent both off for repair which this time seems to be an improvement and the popping absent.

I can't recall running them at a high volume since I got the D600 but I have always lowered the output to the D600 compared to that the M1 from the control panel of the Terratec. I can push the control panel higher but then get distortion.

Having got both amps repaired and sounding much better I tried to run them at higher than normal volume level and can not get to that floor bouncing earth shaking level that forced them to switch off to protect the threshold of hearing. I have run the M1 just below the level that they cut out with the cannons of the 1812 and the Firebird suite on LP. These levels are not comfortable in a small house.

I am happy with the quality but just puzzled by the lack of punch at higher volumes and don't know if it is the speakers or the 101b output.

Hi Difficult to analyse unless you can connect to a modern pre

Regards I

I check the cables and tried alternatives. I also feed the computer output into the tape compared to the radio input. Tape is lower volume level.

I also feed the direct output from the Terratec DMX6Fire USB to the RCA input on the M1. This level was lower still.

The 101b may not be passing through the signal at the level it used to but the M1 amplifiers are not responding as they once did.

Thanks for the help.

Do you know what was changed?

There were 3 revisions to the M1, maybe the input sensitivity was changed on the later models to keep up with more modern kit?
Many power amps that had revisions saw this, some of the early amps were 200ma, then 0.5a and then 1.0a, this makes a huge difference to overall gain for a given input.

The main smoothing capacitors had given up after all these years and leaked out their electrolyte. Both amps have had new ones fitted.

The M1 where a new update between the time I started auditioning and placing my order. So I suspect they would be the second variation. Meridian did check them out at the time the 101 was upgraded by them to 101b and I got a new Moving coil module.

Was sensitivity changed as part of repair?

Worth also pointing out that D600's were multi amp, so not just 1x70w amp. Not sure how many amps M1's had.

Also, if D600's were like 200 series, volume went iirc 0-64 not 0-99 like modern kit, so yes, above 60 would be very loud.

I believe the M1 has three 100 W amps. I don't know if anything else was changed with this repair, just the main smoothing capacitors. Relays had been changed in 2010 and 2011.

M1 circuit

0-64 would explain the loudness and unpleasant feeling at over 60. I couldn't leave them at that for more than a second. Must be clipping.

The handbook says a dealer can select 0db (775mV) or -20db (77.5mV). I have been using the 600 ohm balanced line.

The handbook is at
100 Series
scroll down the page and click on the thumbnails to view.

The 101b needs checking out and measuring levels. Perhaps the M1s need another expert technician's look as well.