Summits; Tubes vs SS

Hi,
I have been running my ML Summits with Pass Labs x250 and x-1 pre, love the sound, but am wondering what tubes would do for them?

You'll have to listen and see.......

as Adam says, allow your ears a listen..............

for the record I love tubes with my Spire's and firmly believe it's an easy match with the current 'hybrid' designed speakers from M/L, keep in mind Logan and Pass are an excellent combo to begin with so expecting a big 'WOW' isn't likely, more like a ..... 'nice' perhaps !!

I found the tube sound brings vocals alive more especially on male voices. There seems to be more bass coming from the panel but the downside is the high frequency gets a little neglected

i use ss power amps with my summits [belles mb200] and am not intending changing but over past few months had lots of pre amps . had audio research ref5se and its sounds sumptious with the summits, the naturalness of deep notes and sense of reality is huge


then i had the new music first baby reference and its incredibly extended sound and wide soundstage, really matched the belles


now i have a puresound L10 which is a good match too , well worth trying all sourts of tubes in your system



would love to try tube poweramps but not sure if could power the speakers properly

I have not had Summits but I do know the International Sales Manager for Ayre uses MXRs with his Summits, I have used McIntosh MC275 X2 and found the Ayre MXR was the closest I could reach to those lovely valve amplifiers.

One more thing worth mentioning here - other than my first post "listen and see".

I'll preceed this by saying that:'
1. I don't use a valve amp with my 'Logans
2. I have heard valve amps and ES speakers (ML and others) sound wonderful.

But

I've also heard more than a few people say that valves and ES is inherently not a good match due to the current requirement of an ES design, and this is a mismatch to inherently high output impedance of a valve amp.

I wouldn't go as to say it is a mismatch because as I said above - I've heard valves and MLs sound wonderful. But moreso perhaps, a valve amp will be at a disadvantage against a SS amp when driving them......perhaps. But let's face it - ES speakers aren't easy for SS amps to drive either.

Joe,

What are missing in your current set-up that you believe tubes will improve?

Be careful what you ask for, you might get it.

GG

It's up to personal preference if one favors tube- or SS-amplifiers, both can operate fine with ML but some requirements needs to be fulfilled. ML has typically low impedance especially in the high frequency range. Typically they are 4 ohm load but drop to and below 1 ohm in the 20kHz area. Voltage sensitivity is around 90dB and since 4 ohms impedance produce ~87dB/1W/1m - loud volume levels will require considerable power output from the amplifier. High current may be needed but typically not so much in the top octaves and hybrid models come mostly with powered woofer section, this makes power amplifier selection somewhat easier. Some tube- and class-D amplifiers may not be well suited for difficult loads like ML.
I have experimented with old Nakamichi PA-7 Stasis SS-amp and ARC HD220 hybrid amp and small Cambridge Audio integrated (can't remember which model), all of them sounded quite nice at normal listening levels. I do prefer tubes for amplification and one nice sounding amp is ARC VT-100 (mkI) which I had for awhile but unfortunately it's not well suited for this kind of loading. Problem seems to be too high output impedance, this is typical to most tube power amps with output transformers. I spend some time trying to find a good match for ML and based on specifications many models not support typical ML loads very well (I definitely wanted ARC). Here are some specs to consider:

ARC VT-100
output tabs 4/8 ohms
output regulation 0.8dB@8ohms
NFB 10dB
damping factor 11

ARC REFERENCE 110
output tabs 4/8/16 ohms
output regulation 0.7dB@16ohms
NFB ?
damping factor 12

ARC REFERENCE 150
output tabs 4/8/10 ohms
output regulation 0.6dB@16 ohms
NFB 14dB
damping factor 14

ARC VM220
output tabs 4/8 ohms
output regulation 0.8dB@8 ohms
NFB 14dB
damping factor 12

ARC REFERENCE 210
output tabs 4/8/16 ohms
output regulation 0.6dB@16 ohms
NFB ?
damping factor 14

ARC VT200
output tabs 1/2/4/8/16 ohms
output regulation 0.8@16ohms
NFB 10dB
damping factor 11

As can be seen compatibility with loads like ML does improve normally with higher powerage amplifiers. I chose ARC VT200mkII as it is highly configurable for various loadings. Output impedance can easily be reduced with higher NFB but this may not be optimal (up to a point) solution soundwise. Tubeamps can generally supply only few amperes output but still sound fabulous if well selected impedance matching with load. Power requirements depends on required SPL by user.

One thig I would suggest is taking a hard look at a hybrid. Conrad Johnson tube preamp with a good solid state power amp preferably 2 mono blocks, I've had SS and tube on my vistas and they were very different,

Dallas said:

One thig I would suggest is taking a hard look at a hybrid. Conrad Johnson tube preamp with a good solid state power amp preferably 2 mono blocks, I've had SS and tube on my vistas and they were very different,

Click to expand...

I'll drink to that!

Dallas said:

One thig I would suggest is taking a hard look at a hybrid. Conrad Johnson tube preamp with a good solid state power amp preferably 2 mono blocks, I've had SS and tube on my vistas and they were very different,

Click to expand...

+1.

That's what I do.

That's what a lot of people do.

This is an interesting situation. I bought an EL84 tube (valve) amp from overseas, but it arrived pretty banged up. After some negotiating with the seller, I kept it with compensation for getting it fixed. I let it sit not doing anything for a while, and in the mean time I got a pair of ML Sequel 2 speakers and a Butler Audio 2250 stereo SS amp with tubes on the output stage, a very cool amp. The MLs sounded great with the Butler amp. I very recently got the tube amp repaired (rated at only 20 EL84 watts) and decided to hook it up to the Martin Logans, just to see how underpowered the EL84 amp was with these speakers, and I was amazed at the sound - full, wide soundstage, smooth vocals. Keep in mind that the custom output transformers are huge and proprietary. If I turn the preamp up (a Transformer Volume Control passive pre, with no gain of its own), it is too loud with all my sources. I listen to mainly jazz and classical, so no heavy rock. I also make my own speaker cables and ICs, which tend to be on the capacitive side, but still it sounds great! (My cables are the reason I got the Butler Amp. I tried my cables on a buddie's system, with his ML SL3 speakers, and he traded me the $3000 (new price) Butler amp for one set of my speaker cables and one set of my ICs).

Can anyone give a technical explanation of why this combination works so well? I thought that MLs needed lots of juice to sound great.

The Butler amp is staying in the box until it is sold.

Gary

joeb said:

Hi,
I have been running my ML Summits with Pass Labs x250 and x-1 pre, love the sound, but am wondering what tubes would do for them?

Click to expand...

Even though I love tube amplifiers, it would take a very, very special tube amplifier to better what you already have. I'm a big Pass Labs fan.