Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems G68 vs 568.2 bass and power supply

I have a 568.2 in place of my G68 while its power supply is being replaced. Wow!

I repeat... Wow!

The 568.2 makes the 4" thick on-wall P350s speakers pump out bass like a boss. If only there was room correction to clean it up a bit.

It will be interesting to see if the G68 can step it up another notch once its power supply and power supply capacitors are replaced.

Any input on the SQ of the G68 with the linear power supply vs the stock 568.2? Part of me wants to mod the G68. Another part of me says just replace the XP ECM40UT31 power supply with the ECM60UT31 (for more current) and be done with it.

I have a second G68. It's bass is stronger than the other G68 but not as strong as the 568.2, at least in an analog system with the G57 amp. While the 568.2 bass is stronger, the G68 bass is bit tighter, even without room correction. This indicates to me that the mod may be worth while. I know there is only one way to be sure. But comments are appreciated before I turn this into a project.

Do the mod, you would not regret.
The lower noise would make the soundstage much more open.

Two G68s sounding that different? Seems unlikely, unless the configurations are different; check them. Subtle things like the second distance "adjustment" in the calibration are actually designed to move the bass wavefronts to optimize the bass for your listening position.

You don't say that you are comparing the G68s in a drop-in scenario; if not, all bets are off; if so, check the configs.

One motherboard capacitor is visibly damaged on one of the G68s. This damaged cap creates a bottleneck because it sits in between the power supply and everything else. This could explain the difference between the two G68s.

I have two 568.2mm in two different systems and both systems sound fantastic.

Funny thing. My DSP5200s were my favorite. When I got the DSP6000s, they became my favorite. Now that I have the 568.2, the P300 series on-wall speakers with SW1600 subs have become my favorite. I think the reason is how the 568.2 drives the SW1600s. All are my favorites for different reasons.

The DSP6000s have the strongest bass and are the most articulate showing the most nuances. I suppose that could be due to their separate cabinets that may be creating a lower noise floor. The P300s are the most spacious and are the easiest to listen to all day. The P300s with SW1600s have a deeper bass. especially with 568.2 driving them. The DSP5200s have a more polished bass. They have the most unique signature.

They all sound different. They all sound great.

I can't wait to mod the G68 and see what happens next.

Good points Axle,

Many can be drawn in to assuming and believing different is better "It Ain't Necessarily So".

Each to their own "Favourites"

Hector

All this talk about replacing the G68 switching power supply with a linear power supply. You know the simplest solution? Get a 568.2. I still want to mod the G68 as a matter of curiosity.

I noticed you mentioned that you wish the 568 had room correction.

You did compare it with MRC off, right? Reducing those peaks results in a loss of bass if you set the decay time too aggressively. That's the main thing that you're tuning when you choose the time. Bass versus boom.

I'd agree that the quantity of bass would be improved with a better PSU in a power amp, or maybe even a marginally designed analogue preamp, but the sorts of currents that the output amps are drawing in a G68 to drive high impedance line levels are nothing compared to what the digital electronics would be taking. If you're using digital outputs then there is no difference.

I moved from 568.2 to G68 years back, and I never really noticed a loss of bass unless I was playing with MRC. My memory of the 568 is fading, though. It's still amazing what could be packed into that little box - it was a great processor. I remember the balanced outputs being incredible into a 557. Miles better than phono.

I'm not trying to invalidate your experience, but it would be interesting to try is as VK suggested - with all non essential settings off.

Yes. I reset the G68 more than once. I don't use MRC on this particular G68 because it doesn't perform as expected. On my other G68, MRC works as expected.

Without enough PSU capacitance line regulation will droop on even high impedance loads. Other circuits - as you say - like digital loads that require high currents will see even more droop. As levels droop signals get sloppier overall, which results in jitter. I think the SQ can be attributed to jitter, which can be attributed to PSU. The fact that MRC doesn't do much on this one G68 vs the other may also be explained by PSU.

Haven't got around to replacing the PSU. I have my music up and running so it's a low priority now. But it's definitely something I have to find out. I will post when I find more.

Thanks.

I am not very sold on some of those... say 'tech arguments'.

But one thing is clear: PSU's DO make a BIG difference in audio gear.

Ask any Naim user with some experience, they know this.

See some other serious products, like Pass Labs XP preamps I am reviewing this days... Model 10 and model 20 are identical but for the external (bigger and improved) PSU on 20... and they are very audible different (I really wished otherwise because I was so tempted by 10... until heard 20!).

Anyone with some DIY skills/experience knows, too... Myself, the Beta22 (head amp) and Buffalo's (DAC) I assembled were quite in another league with the proper PS.

The 568 does have a quite good linear PS, if a bit primitive: just one transformer (and sometimes a bit noisy btw) but separate secondary for digital and analogue supply, and several 317/337 regulators (pre and local). The regulators work a bit hard here and this is why the unit feels so warm on the outside (even on standby, there is almost no difference in power draw... pre-green days!). If you live were I am, change 'warm' for 'hot' as I measured 60 and over ºC inside... Heat is enemy of long-living capacitors, thus a 568 may need replacing some elcaps with time (over 10 years anyway).

Other than that (very minor!) 568 is such a great unit! Just as a stereo DAC+preamp still delivering at top level (and able to do several other tricks too).

Regards!

There's always a reason... and the reason is always technical.