Review: Classe Audio 70 Amplifier

Category: Amplifiers

This was purchased from fellow Audiogon Member this past summer. For all practical purposes this amp is in like new condition and came with box and manual and not a flaw to be had.

Had always wanted to try a Classe amp and had heard some very good things about the Classe brand. The Model 70 had impressed me several years ago with its musicality and that first impression remains true today. With the Model 70 Classe remained true to their doctrine that all products regardless of price must deliver the music with astounding depth and clarity. The Model 70 does that with exceptional ease. New these sold for $1,195.00 and sell now for about half that amount. Have kept their value well and continue to deliver one dynamic performance after another. This one of the very best class a/ab amplifiers I have ever owned and I have owned some of the very best in the last 47 years. Been in this hobby since 1957, so I can speak with some knowledge.

The Classe 70 is mated to a Marsh P 2000 pre-amp driving some vintage Time Window speakers and I could not be more happy with this current set up. This is in my second system,that now I am listening to more each day. In fact the Time Windows have never sounded better, the Classe does a remarkable job of extracting the best from the Time Windows.

The initial program material I listen to was Chris Botti "Night Sessions". One of the more 3 dimensional presentations I have heard. Sounded as though Chris was in the room. Next up was Earl Klugh "Sudden Burst of Energy". Another unexpected experience. Earls guitar just jump to life and if one listens closely can hear Earls finger work as he strikes the strings. Amazing definition. From there just had to try some Rock n Roll and used the venerable Santana Abraxas recording for its many instruments and tonal qualities. Once again my expectations were not disappointed. The Classe 70 can rock and deliver bass with authority that belies its power rating.


75 Watts stereo,high current design,sleek curved slimline chassis with dual heat sinks at rear,both regular and fully balanced operation switchable.

Frequency Response : 20Hz to 20KHz +/- 0.1 dB

Sensitivity : 900 mV in for rated output

Input Impedance : 70 K Ohms

S/N Ratio : More than 100 dB

Rated Output : 8 ohms 75 Watts Stereo

4 ohms 150 Watts Stereo

Dimensions: Gross : 22"x 19 1/2" x 10 1/2"
Net : 19" x 11 3/4" x 4 7/8"

Weight: Gross : 35 lbs
Net : 30 lbs

The Classe Model 70 will have a very long time in my second system. It does the one thing I ask all Stereo Components and that is to deliver the music with depth,clarity,detail and transparency. I does so with amazing ease.

For me this is as good as it gets for Class A/AB amplifiers. If there is better out there in this price range I have yet to hear it.

Associated gear
Marsh P 2000 Pre Amp,Sony CD Player,Denon DVD Player,DCM Time Window Speakers.

Similar products
Bryston 3B,Parasound Halo,Rega,Sim Audio,Muse,etc.
i also liked the 70 the first time i heard it,if you get a chance take a listen to a yba amp 2 , it has much more of everything that the classe has.....and its also upgradeable with external power supply's......only if you get a chance to!
Ferrari, I once owned this amp too, and at the time, it was the best amp I'd had thus far. That was early in my audiophile journey however, and I was able to surpass its performance pretty quickly when I moved to a Conrad-Johnson MV-55 tubed amp. I remember the Seventy's strong suit as being bass authority for such a compact, moderately-powered amp. It handily outperformed my previous NAD 2200 in all areas, sounding much more at ease even though it was rated at 30 fewer watts.

But I could never be completely satisfied with this amp, due to its stereotypically 'solid-state' sounding 'cold' or 'hard' harmonic structures, overbearing bass relative to its darkish highs, dodgy imaging (it wandered with frequency), and residual opaqueness that prevented it from resolving fine reverberant details. When I got my C-J (though it has since been replaced, in another big upgrade, by VTL mono's), it was like breathing a sigh of relief, as everything just got much more coherently natural-sounding and open, despite its being rated at only 45 watts (this was all with Thiel CS2.2's). Piano sounded a lot more like a piano, instead of some 'electro-mechanical' reproduction of a piano. Ditto for voices. Instrumental images sounded fully integrated with their acoustic surroundings, rather than artificially detached.

But the Classe was well-built and trouble-free, and I'm guessing it would still beat many mass-market receivers around the price it goes for used in terms of fullness and body. I'll also mention that it was extraordinarily sensitive to a power cord upgrade, and wasn't nearly as listenable until I had done this (at the time, I used a Synergistic Master AC Coupler). I wouldn't call this amp truly 'high end' today, but as an inexpensive knockabout spare for use in a second system or with a subwoofer it'll serve. Obviously, you and I have a fairly divergent assessment of the Seventy's overall musicality, but even so, happy listening! :-)
I'm glad your happy with the 70.
I owned a Classe 30 pre amp that was built during the same period as the 70.It scared me away from Classe products forever.Muddy,dark,shut in with low resolution.A terrible product.Never again for Classe with me.
Happy holidays.
FWIW, I believe that the older and generally well-regarded "DR" line from Classe, as well as many of the products they've introduced in more recent years such as the Omega line and its trickle-down descendents, were not primarily designed by the same lead engineer as was the Seventy and its kin, so Bigbry's and my conclusions about those products shouldn't, needless to say, be extrapolated to all Classe gear. The Seventy was after all - as Ferrari pointed out - somewhat of a 'budget' amp in audiophile terms. However, why this model remains fondly remembered, or is still used, by more than a few audiophiles is something of a mystery to me. I mean, Ferrari has been at this since before I was born - do we really hear things that differently? :-)
I too have owned and found the Classe Seventy to be a very musical amp worthy of the excellent praise it received in The Absolute Sound when it was in its early production. I know many other well seasoned audiophiles whose ears I trust that feel this was an excellent design and a great deal for what it cost.

What I find somewhat sad are the responses from Zaiksman and particularily Bigbry. Based on one of Classe's entry level preamps Bigbry feels the need to criticize not only the model Seventy, which he's never even heard, but the entire Classe line. Bigbry, I'm curious what the point of your post is since you obviously have no real experience to offer, just negative criticism of what another member has found to be very nice. I have not heard the 30, but I have extensive experience with with the DR-6 and CP-60 preamps, the DR-15, CA-300 and CA-100 amps, as well as the Seventy and they are anything but "muddy, dark, and shut in with low resolution."

Zaikesman, you obvioulsy fall clearly into the tubes are better than solid state camp and I'm not about to argue that the Seventy is better than the CJ MV-55 since I've not compared them, but they are a different approach and suit different tastes and systems. But come on, comparing the Seventy to mass market receivers? Put into the right system the Seventy is a very musically satisfying amplifer and represents a very nice value at current used prices. Obviously Ferrari has found this to be true in his system, and as you have mentioned, so have many others. So I ask you as well, what is the point of your post? To me it is just critical of what another member has found to be excellent based on their taste and experience. Finally, you might want to be a little more sure of Classe's history of design before posting. All of the early designs with the DR designation were designed by David Riech (sp?) when Classe was a very small company. The DR designation was dropped when DR left and Glen Grue(sp?)took over the company and its designs. The Seventy, Ten, Fifteen, and Twentyfive were all designed by GG as were the preamps, but retained similarities to the earlier DR designs. Of these the Seventy and Fifteen were the most popular. Classe has grown into a large company and today, according to one of their techs, a design team is responsible for their designs.

Thanks for your post Ferrari, I enjoyed reading it. I have also heard very nice things about your Marsh preamp and it sounds like a good match for the Seventy. I found it interesting your use of the DCM Time Windows, a very inovative design in its day and apparently still very enjoyable today in your system. Enjoy the music!
One only has to look at the similiar products in the review to understand where I placed the Classe 70.

By no means can the Classe 70 compete with esoteric tube gear or high end Class A output amps such as Pass Labs,Threshold/Forte. Nor can it compete with the Classe DR line.

But for what it is I find it is one of the true bargains of high end. The Classe 70 has in recent times become somewhat of a cult item such as the NAD 3020 and others that have held the test of time.

Few of us will ever own FM Acoustic gear. I just cannot justify $30,000.00 for a preamp and $50,000.00 for a Power Amp. While that gear represents the pinnacle it is just not for the mass crowd of high end. Plus most of us just do not posses the golden ear to fully appreciate.

This review was to let the budget minded among us, that this product is of merit. Two channel audio is an ever evolving process and that few of us will ever own the crowning achievement of the designers art. With that in mind this review was presented.

Many thanks to the respondents of this review, your opinions are most welcome.
Well Ferrari, you did say "for me, this is as good as it gets for class-A/AB amplifiers", which I took to mean all class-A/B amplifiers, which means the vast majority of amps on the market. That's a pretty strong endorsement, even if you limit it to the Seventy's price range, and the other amps you list probably aren't chopped liver. This makes me wonder whether I could ever be happy with relatively inexpensive solid-state sound (something I haven't attempted to survey). For the record, I bought my C-J MV-55 as a demo for about $200 less than the Seventy went for new, so I wouldn't exactly call that tubed amp "esoteric" - never mind costing as much as a luxury car, so I'm not sure where the FM Acoustic comparison comes into play. (BTW, I bought and then sold my Seventy for $450 each time, and would question spending more on this piece.) The MV-55 also has its shortcomings to be sure, though to me they're more tolerable, endearing even, than are the Seventy's. Again, I cannot see why the amp I heard and lived with would ever become a 'cult item' as you say, but as a 'starter' amp like it was for me, I suppose worse could be done for the money if you're stepping up from an NAD or Adcom. Thanks for posting the review and your gracious response to my demuring.
Tnadu: You asked, "But come on, comparing the Seventy to mass-market receivers?"

What I said above: "...I'm guessing it would still beat many mass-market receivers around the price it goes for used in terms of fulless and body." Well, so would a Krell monoblock - why do you take this to be some sort of slam?

You also said, "You might want to be a little more sure of Classe's history of design before posting." You then go on to say essentially the same thing I wrote in my post, which is that the lead designer for the Seventy was not the same guy as for the DR series or their current offerings - a point I raised in response to Bigbry's post, who's somewhat careless inference about Classe in general (true as his reporting may be for him personally) you also took exception to. Although I had forgotten GG's name since I owned the amp, again, just what is it about my words that you're attempting to call out here?

As to your supposition that I'm simply a tube kinda guy who'll never like SS, I wrote: "This makes me wonder whether I could ever be happy with relatively inexpensive SS sound (something I haven't attempted to survey)." That is as honest and open a statement of my position on the question as I can fathom a way to write. Sure, I like tubes, but that doesn't mean I like just any tubed amplifier. By the same token, don't read more than is there into my wondering about affordable SS - a few of the most accomplished amps I have ever auditioned were solid-state. For instance, I have no reason not to think that Classe's top offerings of today might not surpass the tubed amps I currently use in many ways - indeed quite possibly in all ways - but I don't know from personal experience, which is why I didn't attempt some sort of definitive pronouncement on the relative merits of the two technologies (and would never presume to do so). Rather, my musings were simply a logical extension of Ferrari's finding that he liked the little Classe better than many of the budget (used, I'll assume) SS contenders he's owned/auditioned and listed as such, which by implication might mean I would prefer my budget C-J over them by an even wider margin than I did with the Seventy. But I made sure to qualify that sentiment with my parenthetical statement that I had not surveyed all the competition, and by noting that Ferrari and I seem to hear differently regarding the Seventy's merits and shortcomings anyway.

Tubes vs. SS wasn't the point of my posts, but I felt that readers should be provided with some sort of context about where my comments were coming from. Please don't try to hang me for being forthcoming - all I'm interested in good sound, not which method one prefers to get there. I will happily affirm that the Seventy will beat out any similarly-priced (new) tube amp I know of in terms of bass slam and weight, although not necessarily overall bass musicality (I found its bass wasn't as open - didn't 'breathe' or 'flow' as well and wasn't as transparent - as I might have liked, and tended to somewhat overshadow the amp's mids and trebles in a way that detracted from its overall coherence). My main point wasn't that the amp was terrible, but that I had a different take on it, and have never understood exactly where its apparently persistent lofty reputation comes from. Obviously, I think it is possible to do much better for not a lot more money on the used market.

You call my posts "sad", ask what the point of my writing them is, and conclude that " is just critical of what another member has found to be excellent...". All I can say is that Ferrari himself seems to have no such qualms about my contributions, which I can assure you are just as honestly reported as I'm sure his or yours are. You seem to think that I, or anybody with a divergent take, ought to self-censor before posting anything negative following a positive review in an open forum. Now, *that's* sad!
High end at best is a subjective endeavour. And yes we all hear sounds different from each other. After all we are human and we all are subject to our environment we have moved in. Based upon this initial review I find nothing I can carp on. I owned a 70 for many years and would not hesitate to recommend this amplifier to anyone seeking fine music reproduction. Based upon the products that were listed as similiar products, I would find this to be a very good base in recommending the 70. After all Ferrari has been at this far longer than I have and that probably goes for about 90 percent of the membership here. That alone speaks volumes.

I have since moved further upstream in audio, but the Classe 70 remains a fond memory. Thanks for the review.
Good to see there is still some spirited debate here. You're right we all have subtle differences in audible perception. The whole point of this is the music, remember the fundamentals... straight wire with gain. The exhausting pursuit of that live performance being realized right in our own living rooms. Well I must say the Classe 70 succeeds in spades in these crucial areas. I never had the pleasure of owning one, but my close friend does. And it is with great humility that I must bow my head and admit defeat. The Classe 70 blows the pants off my Krell KSA 300 S, and I've owned many other fine amplifiers like Sonic frontiers, Cary, Audio Note, Spectral, Mark Levinson, YBA, Conrad Johnson and far too many more. And Please stop with the tubes. Be honest with yourselves, how long did it take you to adjust to that tube sound... 6 monthes... a year, I never did! Exagerated mid's, rolled off highs, they can have em. The only real experience that has become important to me is how MUSICAL and INVOLVING the amplifier is. I'm sorry to say to Zaikesman,who said "Easily able to surpass the sound of the Classe 70". Not a chance!! You're talking to a previous owner of a DR 2. And yes... The 70 beats the beasty DR 2 as well. I won't even respond to Bigbry's comments. Once in a while, along comes an amplifier like the CJ Premier 5,Mark Levinson ML 2's, Spectral DMA 180, Mac MC 240, Pass Labs Aleph 0, and so on that gets it right! Classe got the 70 right. That's why everybodies talking about it here, that's why I've seen a couple of fellow audiophiles almost cry after selling theirs, and thats why there highly sought after. Congradulations Ferrari you now own one of the most musical amplifiers in the world...Bar none!!
Fascinating. Maybe I should've held onto mine and sold it for the big bux after everybody reads this thread... :-)

As I alluded to above, it had been a long time since I'd had a solid-state amp in here, and I was curious what might be done today in the way of a moderately-priced one, along the Seventy's general lines. Well, I solved that by going and buying a McCormack DNA-125 from a fellow 'Goner not too long ago. Compact, inexpensive, well-reviewed, power MOSFET's, cult-like following - but almost double the wattage.

This amp was a very pleasant surprise for me. In fact, it showed up some shortcomings with my VTL tube mono's that I ultimately traced to some failing tubes. It's good to have a SS amp around just as a point of reference for consistent performance. I would rate this McCormack much more highly than my Seventy. It's not perfect, but I find it easily more "musical" and "involving" - and just plain competent - than the older Classe. Some of you guys should try to hear one (well warmed-up).

However, after flirting for a few days, when I finally got my tube situation straightened out it became clear that the silicon-hearted amp was never going to tempt me away from my fire bottles. I find it interesting Scanton that you feel tubes always sound rolled-off up top - I've never heard a sub-mega-buck SS amp that sounded as open through the treble to me as an above-entry-level tube amp usually does. It's also interesting that the oft-expressed sentiments about 'musicality' and 'involvement' are being turned by you against tubes, because that's usually exactly what people who love tubes argue to those SS'ers who complain about specs and bass...

Anyway, to answer your question about how long it originally took me to "adjust" to tube sound in my system? - About 30 minutes..."honest"!
Well this week end was most interesting to say the least. Several people showed to audition the Acoustat Model 2 speakers.

Not wanting to dismantle my main system for this audition I used the Classe 70 Amp, Marsh P 2000 PreAmp and the Classe CDP .5 CD Player. Used the standard factory supplied power cords with each unit. The interconnects were the old Golden-ens(remember those?) for PreAmp to Power Amp. CD interconnects to Pre Amp were just standard Sony issue I had here,never used. Speaker wire was the Original Monster Cable from about 1982 or so. Basically just to show the Acoustats worked for the prospective buyer. Had the Acoustat Model 2 plugged in for about 3 days to help stabilize them. Usually takes 7 days for the transformers to really come on line.

What ensued was quite remarkable, even as jaded as I am, was taken aback. First I did not expect the Classe 70 to be really able to handle the Acoustat load. Acoustats have a widely varying ohm load and are quite reactive. Takes a very special amp to handle Acoustats. Before the first customer arrived fired up this system and was totally amazed at the ease the Classe 70 was driving the venerable Acoustats and at very loud levels at that. Oh well perhaps a little prejudice here, the real test is the customer response to this system.

First gentleman to arrive had brought his own amp and speaker cables to audition with the Acoustats. After hearing what I was playing, decided it was a moot point to bring in his amp. Which was far costlier and very high end to boot. I left him to his own devices as he had brought many CDs he wanted to evaluate on the Acoustats. He spent well over two hours here. He just couldn't get over the sonic signature he had been hearing. Kept saying seamless,liquid and detail he had not heard before. And was totally floored when he as informed no special cable or interconnects and 22 year old monster cable. He had admitted visting several high end stores locally and had heard nothing that came even close to this.

Next person came over with his amp and once again decided just to audition the CDs he brought along. His amp was an Audio Research D120 recenlty back from AR service. The result was very much the same as with the first person,totally amazed at what he had heard. I think his wife opposed the Acoustats due to their size and room decor. Who knows I think he will be back.

Third person over was a gentleman from a very well respected name in High End Audio, although I did not know this until he handed me his card at the end of the day. This was not the usual audition, he really knew his way around high end gear. Totally examined the entire system, ask what power cords, interconnects, speaker wire, any mods to the Classe or Marsh or Classe CD Player, told him all stock out of the box units. He made the comment that he would not have belived the Classe 70 could power the Acoustats let alone produce the signature that it produced.And noted that the Classe heat sinks were quite warm but one could leave there hand there without discomfort. He as well had brought a lot of CDs to audition so I left him to indulge. As a last request he wanted me to open remove the top of the Classe 70 amp so he could have a look inside. Oh well what the hell, complied with his wish. Remove the top, he examined so closely that i thought he was going to climb inside. You're right he said, factory stock, no mods. This is a most remarkable system here. I almost do not believe what I am hearing. Plus the stock cords,cables, and speaker wire! He informed me who he was and that this was one of the top five systems he had ever heard-period! This coming from who he was totally stunned me. Lets face it I literally threw this together just to audition the Acoustat Model 2 I wanted sell.

So here's the dilemma is the Classe 70 really that good or is it the combination of components? This is the first time I have put the Classe 70 to the Acoustat Model 2 and must say it does sound fabulous, much better than I had ever thought it would. I wasn't interested in selling the entire system, so that may have been the reason they haven't sold as of yet.

At this point may very well keep the system. To say the least a most interesting week end. The Classe 70 performed far above my expectations, and I already like the Classe 70 very much indeed, but this has been a total eye opener for me.
Guess I owned the wrong speakers (hell, the wrong system) to go with my Seventy...enjoy your 'new' system! ;^)

Seriously, I still find it impossible to beleive that the amp I knew could make sound to draw such raves - *unless* something was wrong with mine unbeknownst to me (it certainly didn't seem so ; the sound seemed about appropriate to what the amp was [better than the NAD it replaced], it looked beautiful inside, and it never gave me a lick of trouble otherwise), *and* we accept the notion that a properly-functioning Seventy *really is* capable of top-rank sound with no excuses (a proposition I would find dubious even if I had never owned one, being as there's no apparent reason for suspecting it to be true). System synergy can trump a lot of things in some areas, such as tonal balance or soundstaging, but IMO it's tough to give a lot of credence to the implication that system synergy could grant superior resolution, purity, imaging, or harmonic structure (as examples of other areas where I thought the Seventy wasn't strongest) to a group of components whose weaker links are known to fall short in those respects when heard in other contexts. And especially when the partnering speaker in question should be stressing the amp much more than the Thiel CS2.2's I used mine with (a pretty kind 4 ohm load of average sensitivity, and not a speaker reputed to wildly prefer the tubes which beat out my Seventy).

I'm curious: Was your independent opinion of the audition combo quite as high as your prospective buyers'? Does the Seventy beat out your own reference amp(s) in this application? If you leave the speakers and amp set up as is but swap out 'better' wires and sources, does the sound not improve? The only scenario I can think of here is that the amp/speaker cable/speaker combination, taken as a sub-system, represents a fortuitously copacetic mixture of electrical properties, that the front-end balance perfectly complements that of the back-end, and that you have the speakers perfectly set up in a room nearly ideal for them. Either that, or your customers can't hear. Or the Seventy, against all odds and reason, is one of the very greatest amps ever made...
I am reporting what the prospective buyers were saying of what they heard. My main amazement was that the Classe 70 could handle and drive the Acoustats-period-let alone drive them so very well indeed. I have yet to use one of my Forte or Threshold Class Amps,nor have I tried other power cords or interconnects. The room is not very ideal carpet on floor no drapes or such on the walls. I would not call it an ideal room at all.

Have two other appointments this week end to audition the Acoustats. So we will see what ensues. Although I have one call back now from one of the first three. Wanting the entire system.

I have spoken with a few people whose opinions I value and have been in high end as long as I have since 1957, actually before high end. It is their considered opinion, that the Marsh PreAmp, and Classe CDP .5 has a lot to do with the sonic signature, both are dual mono operating in class A output.

I haven't listen to the system since Sunday night and won't listen to it again till Saturday when the prospective buyers arrive to audition the Acoustats. We will see once the Acoustats have had more that 7 days to season in.
I just picked up my second Classe Seventy, and it has some differences between it and my first one.

The serial numbers of the two units are not close at all.

They are both stock, but one has blue power supply caps, and the other has red ones. One has Motorola output devices and the other has Toshiba. The values of the resistors in the output stage are also slightly different.

I will take a closer look later on and post more details on the variations between what appears to be an early and later model.
Sat - Have posted pics of the Classe 70 that I wrote this review about it does have the red caps. Cant post pic here will open another thread.
I believe mine had the blue filter caps - certainly not red anyway. Couldn't tell you about the serial # or transistors (if I had to guess I'd probably say Motorola, but that's far from certain). Does anyone know if the blue cap iteration is assumed to be earlier or later?...
I have the DCM Time WINDOWS MODEL ONE SPEAKERS . Can you tell me where to get the covers for them . The foam is getting old like me .

Berrie Smith
I have several pictures from the insides of a Seventy I owned last year. I loved the amp's detail, but it didn't produce enough useful low end, and I thought it sounded brittle when pushed. Quite frankly, I'm glad to be rid of it. I can email the pictures to anyone who is interested. Red power supply caps, green and black transistors.