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New or Old power amps?

tinturkey

tinturkey

pfm Member
Hi,

Just a quick question.

I recently had the luck to find and purchase a pair of Exposure 16 Mono power amps. I haven't had the top off but l would imagine they date from the mid/late 1990's or even earlier. They do sound very good through a pair of Revel f208's. I've tried them with a Benchmark DAC2 HGC as a preamp but found that that just didn't have the drive to get the Mono's going. I am using an Exposure 21 pre with them at the moment but l would imagine that l could do better with a more recent pre.

My question is, has power amp technology changed that much over the years since the Mono 16's were manufactured? Would l benefit in sound quality if l were to change them for say a pair of Leema Hydra ll's. OR, should l keep the 16's and find a preamp that would give me more detail and finesse than the 21 pre?

Look forward to hearing peoples thoughts on this.
 
Power amp tech has changed a lot, with Class D and certainly fewer behemoths using tons of power in a very en-ECO way. However, despite having heard more than a fair few feted modern high end designs, nothing modern has come close to the old Exposure IV dual I had for a while. Very ugly but very good. Your monoblocks have the superior reputation if I recall, although there are posters here with more knowledge than me on that. I'd be careful with the assumption that the 21 can be easily bettered, too. As for them still performing as well as when they left the factory, that's a different matter at that age. Some components change over time. A call to Exposure's service department for advice would be my first port of call.
 
No, power amp technology (in conventional power amps) hasn't really changed BUT, then as now, there are big differences between the sound of different amps. I rate Exposure as good but not exceptionally so personally. Ultimately a little over warm and lacking transparency I would say from spending quite some time with IV Dual regulated and earlier with VIII in the past. I offer servicing and re-capping for Exposure and all similar makes.
 
I may be telling you something you already know; but the XLR inputs are not balanced, in case you were using the Benchmark XLR outs (which are).
That may (or may not - I'm no electrical engineer) account for the mismatch.
 
The old days when U.S ‘substations’ were imported at huge cost, to achieve the legendary “bass slam and effortless dynamic swings” that would show up the weedy black biscuit tins made here, are surely gone now with Class D. You can buy a B&O Ice power Edge 1200AS2 for £600-700, that you could pick up with one hand and would take on the most recalcitrant speakers with aplomb. The same US companies are now sneaking them into their sculpted aluminum boxes and sprinkling on the magic fairy dust. It’s a type of democracy that must be getting right up KK’s nose. :)
 
The 16 Monos are legendary (and rare) amps and are hard to surpass at any price. I regret selling mine, although I replaced them (eventually) with the new 5010 monoblocks which I think are at a similar level. Arkless's comments about the Exposure amps he has heard do not apply to the 16 Monos, which are much better and more transparent than the 4DR (also a great amp, btw).

The 21 is a natural partner for the 16 Monos. They can certainly benefit from a better preamp if you can find one that you like but you may have to spend a lot to do so. I used an Exposure MCX with mine, which was better than the 21, and now use a 5010 preamp with my 5010 monoblocks. The 5010 preamp would work perfectly with the 16 Monos, is a better preamp than the 21 while keeping much of the Exposure sound and would be a perfect cosmetic match.

However, the 21 is still a great preamp (and something of a bargain) so I would second the suggestion of having the 21 and 16 Monos serviced by Tony Brady and then re-evaluate whether you need to upgrade the preamp at all.
 
Having recently done some research on P.A power amps for subwoofer duties, it seems that the big old amplifiers with huge transformers still do bass better than the newer lightweight amps, except for the very best of the new smps amps that are on par.

A lot of the new amps cannot sustain their rated output for more than a couple of ms and that’s if they can make the rated power to begin with. This isn’t generally a problem unless you like to play Dubstep music at ear drum busting levels.
 
The old days when U.S ‘substations’ were imported at huge cost, to achieve the legendary “bass slam and effortless dynamic swings” that would show up the weedy black biscuit tins made here, are surely gone now with Class D.
Click to expand...

Well, there ain’t no substitute for cubic inches - so I’ll take an old amp or two you can barely lift, thanks.
 
Thanks all for the contributions on my post.

My original question I think has been answered. Power amplification technology (other than Class D etc) hasn't changed that much over the years.
To be honest I'm very sure there isn't anything at all wrong my amplification - may need a service I suppose but from what I've heard and read Exposure gear isn't quite the same as say Naim in that department.
I think my problem is that I'm a box swapper and after all my years in hifi should really learn to listen to the music and not the gear!!!
It is nice to have a change now and again though so a may try a different preamp - maybe the 5010....
 
Wilson said:
Perhaps the 21 and the 16s are due for a service? I would contact Exposure.
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Id agree with this. Maybe those 16's have been on for 20 years and / or driving a real tough load. The 21 maybe needs a look at too. These were Exposures top amps back around 2000. The modern equivalents are the current and new 5010 pre / monos .
I also think the 21 pre is an absolute bargain at the current prices. I have had mine for 20 + years. It really is a belter. In my main system it took a late and rather expensive Naim Nac52 to supplant it. All other pre amps ( and no pre amps too) failed . I seem to like pre amps with massive power supplies and lots of volts at the output.
The new 5010 pre would be interesting to check out. And also the monos as they are now a more manageable size . I nearly bought the 16's new in 2001 but they were too big. Eventually I went the alternative route of DV Hx1.2 / Chord 1200 power amps for the main system. Still kept the Exposure 18 monos mind you. Fantastic things.
Still all used now and then - nothing gathers dust here.
 
TheDecameron said:
The old days when U.S ‘substations’ were imported at huge cost, to achieve the legendary “bass slam and effortless dynamic swings” that would show up the weedy black biscuit tins made here, are surely gone now with Class D. You can buy a B&O Ice power Edge 1200AS2 for £600-700, that you could pick up with one hand and would take on the most recalcitrant speakers with aplomb. The same US companies are now sneaking them into their sculpted aluminum boxes and sprinkling on the magic fairy dust. It’s a type of democracy that must be getting right up KK’s nose. :)
Click to expand...

I like the fact that Class D is energy efficient and generally takes up less room than the behemoths of the past (and the present) - but as a technology, does Class D 'sound' better or at least comparable to the heavier larger equivalents?

Do you still think audiophiles are buying with their eyes (size and bling) and judging by the weight and price rather than just accepting the fact that Class D is now cutting the mustard at both more efficient pricing and efficient electrical properties but of course tend to look a tad more boring and less manly as a compromise?
 
I didn't really get on with Class D amps. I tried a NAD M2 integrated a few years ago and after about twenty minutes it literally made my ears hurt. I've also tried a pair of Bel Canto M100 MkII's and they had nowhere near the weft (in the bass) of a full A/B power amp. Where solidity down the bottom end big transistors are the way to go.
 
beammeup said:
I like the fact that Class D is energy efficient and generally takes up less room than the behemoths of the past (and the present) - but as a technology, does Class D 'sound' better or at least comparable to the heavier larger equivalents?

Do you still think audiophiles are buying with their eyes (size and bling) and judging by the weight and price rather than just accepting the fact that Class D is now cutting the mustard at both more efficient pricing and efficient electrical properties but of course tend to look a tad more boring and less manly as a compromise?
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The fact that Jeff Rowland and other hi end manufacturers have switched, tells the story. Their customers aren’t disappointed on SQ or they’d walk and the benefits (notably a better manufacturer margin $$$) are there. The CNC, milled from a billet of space grade aluminum and boutique sockets will create an impression of desirable luxury, but purely on SQ terms, Class D is good. Strip away the frills and you can get refined 700w pc for well under £1k! That allows budget to be reallocated to say a DAC with variable outputs running DSD for beautiful results.
It has, to my ears a slightly dry sound ( perhaps fine harmonics and air a bit reduced) but it’s more than made up for by resolution, soundstaging and effortless dynamics. I dare say other great SS and valve designs will deliver beautiful performance but at a cost and you may prefer their signature but in bang for buck terms, Class D is a long awaited triumph for the consumer IMHO.
 
Arkless Electronics said:
No, power amp technology (in conventional power amps) hasn't really changed BUT, then as now, there are big differences between the sound of different amps. I rate Exposure as good but not exceptionally so personally. Ultimately a little over warm and lacking transparency I would say from spending quite some time with IV Dual regulated and earlier with VIII in the past. I offer servicing and re-capping for Exposure and all similar makes.
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What do you consider as exceptionally good amplifiers?
 
Krell, big Musical Fidelity's, Radford valve amps and then only certain models from these brands. There will be others, and I suspect more valve amps as a percentage have "the magic", but although I get to hear a lot of amps I've heard less than I could count on one hand that really do it...

There are very few genuinely exceptional power amps around. Most amps, although they all sound different to a degree, are more united by similarities... in that they balls up the same things in the same ways!

Almost all share the same lack of ability to keep everything separated out properly when there's lots going on. It all becomes a bit of a "wall of sound"...

With the best power amps, music seems to leap out of the speakers rather than be pushed.

You will hear very clearly that those quiet backing vocals are 2 men and a women and are about 20' back rather than "yeah I can hear the backing vocals somewhere over there".

The harmonics of instruments are correct which gives the correct timbre to instruments (a disc I have always sounded like there was a flugal horn present until I heard it with a truly exceptional amp which revealed it very clearly to be a flute!).

Things like gently strummed acoustic guitar which were obviously there during the quiet intro are revealed to not in fact disappear from the mix when the whole band comes in but stay there, very clearly and without "having to listen out for it".

The difference between say a Naim/Quad/Exposure/"insert most amps here" and one of the few that gets it right is quite a revelation when you hear it and could have one thinking that maybe the power amp is the most important link in the chain after all...

If you get the chance to buy a Radford STA25 MkIII or a Musical Fidelity NuVista 300 then sign that cheque!
 
There was an article in HFN/RR entitled "Old Amps for New" mid 70s iirc.

The review referred to a phenomena called "The Ricochet Effect" where sound pressure levels ricochet around a sound room and returned to the amplifiers O/P stage via feedback through the bass drivers.

Comparing a Crown / Amcron DC300 to a pair of Leak TL50+ power amps.

He found that the TL50+ with the triple loop feedback circuit gave a much better performance than the DC300 and was just as loud, in spite of the fact that the DC300 had 6 times the output of the Leak TL 50+s.

Strange that, he ended his review with.
 
Dozey said:
Doesn't loudness depend on amp gain rather than power?
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NO!!!! Vol control position does though and one hears the old "wow it's that loud and only on number 1!"... it probably clips on like 3! For the hard of thinking vol control position has nothing to do with power either... unless you are in Spinal Tap of course!
And no a 50W amp won't go louder than a 300W amp... misleading in that TL50 are 50W monoblocks but DC300A is stereo amp of 180WPC so 100W V 360W . I measured 0.003% THD from one of those old boat anchors! Still has about the tightest bass around...
 
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