The best amp available in it''s catagory

Switches, Switches, Switches

I had Fisher 400 and 500C tube receivers. I used to have fun letting others compare their transistor receivers to one of my Fishers. One even said that my Fisher distorted the sound, as it sounded so radically different than his highly reviewed receiver. His receiver almost completely masked the grit Boz Scaggs voice. Finally in 1990 a friend challenged me with his Proton D940 receiver. It sounded almost identical to the Fisher! I was in heaven and bought a Proton. The switches are very poor and need to be cleaned. I built some Dahlia speakers designed by Dick Olsher of Sterophile. They have an awesome Audax 8” midrange/woofer. The Proton has a Bass switch for 8” speakers. It extended the bass of the Dahlia speakers electronically to where a subwoofer was not needed. It was great to not have a crossover in the upper low range. The Proton has a natural, warm, detailed and open sound. The Bass is very solid.

Similar Products Used:

Fisher 400, Fisher 500C, Harmon Kardon hk670

DPD by far....6db of headroom! Bass EQ too....

switches switches switches....they're junk

Without doubt the best sounding receiver I've heard, although I must admit I haven't listend to many 1,500 dollar plus setups, so I guess my experience is rather limited in this respect. Anyway, I bought the unit for $299 I THINK (may have been $199....can't recall since I'm going back, ah...11 years now) from Crutchfield back in 1991. They listed it as a closeout. I've had my Klipsch Heresy IIs hooked up to them. Low and behold, I ended up moving from NY to CA back in '98 and I left the thing at my former job where a friend of mine was trying to clean the switches due to their notorious reputation. It got to the point where you had to have the audio "listen" switch half-way between it intended position to hear the device you were listening to. Then I started getting intermittant (sp?) play from the right channel. A tap to the front of the receiver would cure this, and it would go back to playing both left & right channels fine. I'm convinced it was the selector switch on the front panel. So, to make a long story short, I took my Klipsch and my CD player and went West. I shortly looked on Ebay for a D940 to buy again but came up empty. Did some research. Bought an NAD 3240 PE which seemed to be an excact clone of the D940 (although it was just an integrated amp---no tuner). Guess what?! Same problem there right off the bat---intermittant play on the right channel and switch problems where they had to be set in the middle of two settings. Heck, they even used the same looking switches! IMHO, it didn't sound as good as the D940, even though it too had 6db of dynamic headroom. I eventually ended up selling it on Ebay to another sucker for the same price I paid for it. Hell, unless someone fixed it, it's probably still circulating on their! LOL. Since money is tight, and I'm a law student with a wife & 2 kids, I ended up buying a cheap Technics 100 wpc receiver from crutchfield for around $129. The thing sounds like pure garbage. Totally. I can't believe what now comes out from my Heresy IIs. My future plan? Track down and buy a D940 and have the thing fixed right and then hold onto it for as long as I have my Heresy IIs (which will most likely be forever--they're 11 years old now and still look and sound like brand new). My question is: Why did Proton and NAD abandon the DPD/Power Envelope feature which gave an astounding 6dBs of dynamic headroom???? Why hasn't anybody else gone that particular route and offer high dynamic headroom units??? In my opinion, it produced the best sound that I've heard when coupled to my Klipsch and I can't understand why the industry has abandoned this concept since the DPD indicator would light up rather frequently to show that the amp was producing high dynamic headroom leavels even at "normal" listening levels. Maybe I'm missing something here....sticking with the DPD feature and just fixing the damned switch issues sounded like a GOOD idea for the company to follow. I even went so far as to ask NAD why they stopped making their Power Envelope feature (via an email to their company HQ) and they basically said it was too expensive and that they took advantage of "newer" technology and hence abandoned the Power Envelope. Huh?! Didn't make any sense to me then and doesn't know either. Anyway, that's my proverbial 2 cents on this topic and if anyone knows anything more regarding the abandonment of the high-dynamic headroom components, please feel free to email me---I'd certainly like to know! LOL :-)

Similar Products Used:

NAD 3240 power envelope (6db of headroom)

Ballsy power amp! The DPD circuit on this thing makes it sound like it has 200WPC, no joke. 2 pairs of output transistors per channel. I measured 117WPC into 2 ohms with both channels driven. Good Schotz tuner. Unit is like a separate tuner/preamp and amp in one chassis.

Like the review before mine, I have had scratchy controls. This was nothind a can of Radio Shack tuner cleaner couldn't fix. My volume control has uneven balance at low levels.

This is a fantastic unit. They just don't make em like this anymore. Where else are you going to find a reciever with a separate amp with a briging switch? This is quite the opposite of many modern recievers that have such wimpy amps that when you have two pairs of speakers, they are put in series!

Build quality is good, looks are good, performance is without equal until you go with separates. Nice moderate loudness curve, along with a neat "bass EQ" that will get you some more bottom end out of a 2-way 8" bookshelf speaker or similar.

I pretty much agree with the previous reviewer's comments.

Similar Products Used:

Adcom separates, Rotel, NAD, etc...

Powerful amplifier, separate "listen to" and "record from" functions, two tape loops, magnetic or moving coil phono pre-amp. with switchable capacitance.

Noisy input switch and fragile solder connections on input plugs.

I have used this receiver on a daily basis for the past 15 years. I have 3 pairs of speakers and a Cambridge Sound Works 3 piece system all running off the unit at the same time (with the use of an Adcom 3 speaker switcher with impedance protection). The amp. has plenty of power to drive all these speakers with no problems whatsoever. Sound quality is excellent. There are inputs for phono with a switch on the back panel for either moving magnet or moving coil cartridge, 2 tape loops, DAD (CD), video and tuner. I've never been too happy with the tuner - perhaps I live in a "difficult reception area". The "listen" (input) switch needs tweaking as it is dirty and has poor contacts and I had to have the phono input solder connections redone once. Other than that, I have been very happy with the unit. They don't make anythink like this anymore. I wish I would have bought 2 when I bought this one for $399.00!

Similar Products Used:

Nothing like it!

Sound quality. Performance. Ability to handle several speaker sets.

Switches

I've had this receiver for over 10 years hooked up to an Adcom GCD600 CD player and Infinity Ref 61 speakers, plus two other sets of smaller speakers, one outdoors.

A lot has been said about sound quality in the other reviews and I fully concur. It is especially good with high frequency sounds (I have a couple of CDs that drive my dog crazy). My wife, who claims she is no audiophile but plays the piano by ear, describes the sound as accurate and "warm". I never imagined one could get such a sound for relative little money.

The only problem over the years has been the switches, and I've been inside the thing a number of times to clean them. The switch that controls the input to the premp has been particularly troublesome. But result has always been worth the effort.

Rather than another round of cleaning, I've just replaced it with a HK3470. But I'm hanging on to the Proton for a while, until I'm sure it really can be replaced.

I have had this receiver for nearly 10 years. and I recently picked up a second one so I could bridge each mono for max 240wpc. The Proton was definitely a great product for its time. There was an intergrated amp version of it too, I think it was the D540, and the tape deck was D740 (but I could be confusing these numbers with BMW models!). Anyway, its build is of good quality with a thick solid metal front plate and quality feeling controls. Unlike other receivers, this one was really a heroic effort at combining the three tasks required of a receiver... Nice tuner, nice preamp, and a great power amp. Each section seems like a quality separate component simply sharing the same cabinet.
The D940 has a decent FM tuner (much better than an average modern mid-fi receiver). And unlike comparably priced receivers, the preamp section of this one offers separate record and play input selectors so you can listen and record different sources. The best part of the preamp is that it has preamp outputs (and the amp section has main inputs). Tone controls unfortunately cannot be bypassed (unless you bypass the whole preamp and go straight into the amp) and there is no remote control. After 10 years, the preamp imparts a slight hiss and many of the controls are noisy. That is why I would recommend this receiver today only for its amp.

Now for the best part, the amp. Unlike the preamp, if you use the main amp inputs (bypassing the preamp) this amp is silent. The concept of the amp is called Dynamic Power on Demand (dpd) which basically means it can output a solid 40wpc with peaks reaching as high as 120wpc without clipping. There is a red LED on the face the indicates when dpd is being used and it gets brighter with higher output levels, so you know visually if you are reaching the limits of the amp. It also offers a button on the back that enables a soft clipping circuit to protect the amp and speakers should those peaks over 40wpc last beyond the amp's ability to maintain it. Another button on the back with proper speaker wiring allows the amp to be bridged mono, more than doubling the output. Now that's a lot of clean dynamic power for a receiver. Put two of these D940s together for stereo and you've got more than enough power for most speakers. The other possibility with two of these amps is to biamp your speakers running each amp in stereo (non-bridged) with each channel running high or low signals to the speakers. I found this option sounded better overall, but it did not allow nearly as much volume as the dual bridged option. After a great deal of listening, I got the feeling that biamping is much easier on the receiver than bridging. The manual says that in bridged mode the amp sees a pair of 8ohm speakers as 4ohms, so I assume the amp is working alot harder. Interestingly when bridged and biwired, the dynamic power on demand seemed a bit erratic... I could get the amp to clip suddenly without the usual predictability of the red LED lighting up.

In conclusion, If you compare the D940 to similarly priced Harmon Kardon and Onkyo receivers/integrated amps of its day, the D940 clearly outperformed and probably outlasts them all. My Carver receiver of the same vintage didn't sound as nice and it melted itself years ago (the Carver had a better tuner and was more powerful but cost nearly twice as much). The Proton is also more versatile than any other receiver of its day. The Proton is very similar to NAD in build and quality and the sound of this amp after 10 years still beats the sound coming from most modern mid-fi receivers. It puts to shame anything from the likes of Yamaha up to $1000 (as far up as I cared to go).

I'll give the pre-amp/tuner section a 4 because it was a great design for its day, but the amp section is a 5. I think I would have to spend around $1000 on a quality stereo power amp to match the sound and power of my pair of 10 year old Proton D940s. Needless to say, they are not for sale.

Amazing Tone! One of the best preamps to get deep realistic bass from small speakers. Accurate sound with lots of headroom!

No remote - but don't let that discourage you.

For years I had searched for the perfect audio amp (under $1000), and in the D940 I found it! I worked in a Major Audio Store for years after owning this amp. I've literally auditioned 100's of mid to high end amps, and this is THE amp for Music. The main thing I was searching for was accurate musical reproduction for Rock and Jazz (I'm a guitar player). I also like "real" bass, like you would hear at an earth-shaking concert or right up on stage. The D940, actually the D540 integrated amp which is the same thing without the tuner, was the ticket.
When I first went in to buy it, the saleperson talked me into a very nice Bang & Olufsen with a remote with about 80 wpc. Ok, for classical B&O is hard to beat, but I'm a Rock & Jazz guy. For Acoustic or Electric Rock and Jazz, this amp can not be beat, period. Anyway, after trying the B&O for about a week and comparing to my friends Proton, I just had to return it and get the Proton (and pay through the nose to do so, but well worth it!). It has been at least 5 or 10 years now and nothing has come close to the sound of this amp. I use small 2-way infinity speakers (6 1/2" woofer) with polycell dome tweeters -- a great match to this amp because they have sparkling highs and handle a lot of bass for their size.
Others have reviewed the awesomeness of the DPD - dynamic power on demand, and it is true I have never heard such headroom from any 40 watt amp in my life (except NAD) and I like the treble frequencies much better than NAD. Just a note, years ago while I was in school, we bridged my amp with my friends D940 and no one we knew had a speaker that could handle the dynamic power (~480 watts/ch I think) without poping the 12" wooofers like a kid pops his bubblegum. Needless to say, we soon disconnected our overpowered living-room creation. Not so much because we had no good speaker that could handle it, but more so we could put our amps back in our rooms (we each missed them dearly).
If you find one of these amps in any condition, buy it, repair it if need be, and enjoy.

Similar Products Used:

NAD, Harmon Kardon, Yamaha, Bang & Olufsen, Onkyo ... and more.

Amazing power, separate "listen" and "record" preamp circuits

No remote, static-y controls

I'm surprised this old dinosaur is still up here--I'm glad
to see that it is.

I bought this as a dealer was going out of business in the
summer of 1989, and actually got it pretty cheap. I'd had
my eye on it for a while because the sound is AMAZING.
As other reviewers have noted, this is like buying separates
in one box. This baby can shake the walls blasting rock
yet at the same time show the deftness of handling needed for
softer classical music. If this thing had a remote, it would
be perfect. You can't adequately replace this receiver for less than a grand.

Mine is pretty much on its last legs, as the preamp is going.
If I ever see another one at a garage sale or something, I'm
buying it, bridging the two to mono, and using my current
reciver just as a preamp. Separates-quality.

Power, Clarity, Build Quality, Design

Preamp section has some noise, No remote

I bought this receiver in 1992 after seeing it first in a crutchfield catalog for $399. Luckily I picked it up for $260 somewhere else, although it would still have been a good buy at $399. I consider it the crown jewel of my system as I realize my other components really aren't up to par. I was mainly interested in the amplifier section as I am not that interested in radio. I was first impressed by the unit's build. It felt solid and seemed like it was made to last. But when it came to power, this amp really impressed me. I originally had it running through a pair of advent 8" two way speakers rated at 125 watts. At full power the proton put so much current through the bass frequencies that it caused the woofer voice coils to clatter loudly into the back plates! This wasn't clipping of the amp- I can tell the difference. I decided to return the advents-not because of the clatter, but because the midrange was dirty. I picked up a pair of lx22 jbl's and was much more satisfied. In summary, I must say that I am very pleased with this unit, it produces a very dynamic and exciting sound. Except like one other reviewer said, I also think that the preamp section isn't up to par with the amp section. Also, the balance switch is crackly and doesn't balance L/R equally anymore-probably a dirty connection easily remedied by some electronics cleaner-a minor gripe. Currently I'm looking to upgrade my system starting my diseased and dying Kenwood CDP. I think the Marantz 5000 might be worth looking into. As far as upgrading my amp, I've been looking at Nad and some other amps, but I have to admit that I'm very reluctant to retire the proton.

Similar Products Used:

JBL, CV, Kenwood, Audiosource

dynamic, clean power...pre-in/main-out...listen/record selectors, gold plated MM/MC inputs with capacitance settings, bridgeable amp, large speaker binding posts to truly hold 12 gauge wire, great tuner.

noisy selector switches, lots of components cramped inside a sturdy frame.

I have only owned this unit for a short time, but have been literally blown away by its performance. This little 40 watt amp packs a big punch and it has 6db of reserve into 8, 4 and 2 ohms!!!! The bass is very tight and the high end is bright and airy. You really do get out of the D940 what you put into it. It won't add or subtract to what is already there. I especially like the record/listen switches which let you record one thing while listening to another. I do not find this preamp/amp noisy and the tuner has an amazing 50 db quieting of 25uv (thanks to its Shotz noise reduction)in stereo. Most audiofile tuners range around 36/37!!! I agree with another reviewer who said the D940 is like combining separates into one piece. With all the features, the dynamic power on demand..some 160 watts into 8 ohms, 380 into 2 ohms, the tuner, the preamp, the solid construction and it's cool looks....how could you go wrong. If one comes available and is in good condition, hop on it and enjoy!!!! (Have some tuner cleaner on hand in case the switches get fuzzy or begin to cut in and out).

Similar Products Used:

NAD