Doug Blackburn
The Noisy Audiophile

April 1997

Belles 150A Amplifier

What does a reviewer do after spending several months with the superb $5,600 Clayton monoblock amplifiers? There's a fairly good chance that most anything else that comes along is going to be disappointing. I really didn't want to review a cost-effective amp for a while. I figured that it would be pretty tough to get enthusiastic about an affordable amp after becoming fully acclimated to the Clayton M-70 monos. But the Belles 150A beckoned - "Come on - It couldn't hurt - Give me a listen."

I'm going to tell you now that this is going to be another very positive amp review from me. You should know that during 1996 I had quite a few less than satisfying listening sessions with products submitted for review. You aren't going to read about those in SoundStage! because they were returned without being written about. Why use the space? Wouldn't you rather read about the good stuff? Trying to write a review of a less than worthy product is not something enjoyable for reviewers. With that in mind, let's get on with the Belles 150A.

Who Was That Masked Man?

Belles (pronounced Bel-less) may not be a familiar name/manufacturer to everybody. Dave Belles has been designing and building amplifiers in Rochester, NY since 1978. His first amp, the Belles A, was a solid state class A design. The Belles 150 amplifier of the late 80s was named one of the 10-best used high-end audio components in The Absolute Sound magazine in the early 1990s for good reason. The 150 was a classic moderate cost (list $795 during the final year or so of production) 75w/ch amplifier. Musicality, lack of common solid state amp artifacts, and solid overall performance set it apart from other solid state amplifiers near its price. In the late 80s, Dave Belles joined forces with the Magnum-Dynalab people. Dave designed and built the amplifiers under the OCM brand. The OCM-200 ($1,600, 100w) and OCM-500 ($2,800, 200+w) were initially a little "slow out of the blocks" but a few running production changes early-on transformed the OCM amps to "best in class" levels of performance. Later on Dave Belles-designed OCM preamps appeared along with the brute force OCM-1600 (around 800w and almost $10,000) monoblock amps. All of Dave Belles's products have received positive reviews in the worldwide high-end press.

In the early 1990s I found myself in need of "the perfect $3,000 amplifier." I went on an amp rampage trying everything I could lay my hands on, new and used, that would not set me back more than $3,000. This included a number of more expensive amps offered at prices low enough to get under the limit. The OCM-500 won the search by a pretty fair margin.

Time passes and the OCM-500 now finds a number of worthy competitors in its price range. Dave Belles is no longer working with the Magnum-Dynalab/OCM folks. He's back on his own, designing and building overachieving cost effective high end electronics. The 150A amplifier is the first product in the new Power Modules, Inc. lineup. I've had 2 brief listens to a prototype of a $1,500 (target list price) line stage that uses rechargeable battery power. This could be an awesome value if the final product sounds as good as what I heard. There was a clarity that exceeded every preamp I've heard so far. Watch SoundStage! for a full review when production units are available. Other new components coming in the near future will be:

Power Modules, Inc. will focus on products in the under $2,000 price range. This is a different and welcome philosophy that will benefit those of us who want the best sound possible but have to worry about all the things in life that limit "discretionary funds." Now that you know a bit about Dave Belles and Power Modules, Inc., let's get on with the review of the 150A amplifier.


Appearance-wise, the 150A is "typical looking." There is nothing unusual or radical about it. The wide faceplate matches the width of the heat sink assemblies that fill the entire left and right sides of the amp. The amp's shape is a little taller and a bit shallower front-to back than many 100 watt/channel solid state amps you see. This is because the transformer doesn't take up much "floor space" inside the chassis. Rather than bolting the donut-shaped torroidal transformer flat to the chassis, it is mounted on a 90-degree bracket with the power supply circuit board. This arrangement has the transformer standing on end requiring some headroom clearance. That explains the taller and less deep appearance of this amp.

The front panel contains simple white lettering, a push button power switch and a green power LED. Inside the amp, the left and right channels are separated far to the left and right sides of the chassis. This arrangement dictates the location of the speaker cable binding posts and input RCA jacks on the rear panel. The binding posts are located near the top of the rear panel. While not as beefy as posts found on more expensive amps, these hex-ended plastic covered posts seem to be quite serviceable. The spade terminations on your XLO, Cardas, DH Labs and Kimber speaker cable will all fit with no problem. The binding posts have center holes for banana plugs. Immediately below the binding posts are the gold plated RCA input jacks. The permanently attached power cord is in the lower right corner of the amp. I would have preferred to have the power cord in the center of the rear panel to help keep it away from speaker cables and interconnects. I was also a bit surprised that the binding posts were above the RCA inputs - opposite what you find on many amps. Neither of these cause problems, but you may have to change your cable routing a little the first time you put the 150A into your system.

The 150A has an "industrial" look, very square and sharply creased. The heat sink fins have sharp corners that are very uncomfortable for carrying the amp. Better to hold the amp under the front and rear sides.


Looking under the hood you see 4 MOSFET output devices per channel mounted on the very large heat sinks. The small amplification printed circuit boards (PCBs) are soldered directly to the output devices and mounted to the bottom of the chassis on standoffs. The 2 amplification PCBs are identical. The center of the amp is occupied by the vertical transformer and power supply PCB. There isn't a lot of built in protection and muting circuitry. You hear a non-threatening thump when powering up the amp. On power down, if you leave the preamp on with a CD or LP playing, music plays for a couple of seconds as the power supply discharges. At that time you may hear a little "zzzz" as music plays on through the discharging power supply. The level of these noises is low enough to not be worrisome. Stopping the music or turning off the preamp makes for very quiet shutdowns. When building an amplifier, especially a high performance cost effective amp, you must decide whether having sound quality degrading relay contacts in the signal path is more desirable than having a better sounding amp that has some harmless turn on/turn off noises. For the kind of sound this amp makes for $1,195, there's no way I'll criticize the decision not to include muting relays.


The 150A could well be THE amplifier to own in the sub-$2,000 range. I even like it better than my $2,800 OCM-500! As picky as I am about amplifiers, I find it difficult to accept that an $1,195 amplifier can impress me this much. I argued with myself about the impossibility of this situation several times before actually writing this review. Understand that all of the positive comments I have about this amp were repeatedly verified. I tried to convince myself that I was being too easily impressed. But when it came time to write the review, there was nothing to do but tell you how good this amp really is.

Bass is very very nice - tuneful, rhythmic, very articulate. It is very easy to pick out a bass line and follow it note by note. The skin tone and reverberation on drums on The Chieftains "Long Black Veil" is excellent, something that is difficult for many amps, tube and solid state. Bass dynamics are impressive, suiting the most dynamic music and movie soundtracks. There might be a little improvement with more power, but 100 watts is fairly potent for my setup. The upper bass and lower midrange can be challenging for solid state amps. The Belles 150A does this range very well. Instruments which can have problems in the upper bass and lower midrange; piano, male vocal, percussion, strings, and winds all sound very good. The midrange has clarity, snap, excellent detail and is not at all musically threadbare. Many solid state amps will make instruments like harp, penny whistle and xylophone sound like harmonic content is missing. This is why some people prefer tube amps' more fleshed-out representation of harmonics. But the 150A does not thin-out midrange harmonics. The lushness of the harp remains, the bite of the penny whistle is there without a hard edge added by lesser amps, the xylophone is full, round and lush without being softened (by tube amps) or hardened (by lesser solid state amps).

The highs of the 150A are not what you expect from lower cost solid state amps either. You will hear some pretty nice sounds up high with the 150A. Highs are not "trapped in the speakers" as you often find in amps under $2,000. You don't get any obvious grit/grain artifacts that plague a lot of solid state components.

This is a very exciting and inviting amp to listen to. Music does not sound dulled or blunted. You get the sweep and scope (or lack of, unfortunately) laid down on the recording. The Art of Noise UK 45 rpm single "Kiss" - a Prince song performed and totally nailed by Tom Jones in a rather remarkable performance for him, the only performance of his I can bear, actually - is rendered in all of its outrageous glory. You get a very nice sense of transition from softer sounds to louder sounds. The music swells to peaks (like live) rather than the stair-step or too-quick-to-jump quality some amps deliver. The slam of the electronic percussion is well done.

The presentation of the 150A is neither in-your-face, nor laid back. It is right in the middle. Where the center image is focused will depend primarily on the recording. When playing symphonic music, you have a mid-hall perspective on the performance. Playing classic acoustic jazz, the instruments will fill the space around and between the speakers with life-size images. Percussion will be clearly behind the other players as it should be on many classic jazz recordings. Good pop/rock recordings will fill the soundstage very well. Vocalists will usually image right between the speakers or even a little behind the speakers, depending on the recording. If you listen to a recording with a mic-swallowing vocalist, the image can be very close to you, well in front of the speakers.


You are probably thinking "OK, but it's a $1,195 amplifier, it can't be perfect." The 150A is not perfect. If you want to hold a $1,195 amp up to State-of-the-Art standards just to pick nits about it:

You have to spend a LOT of money to get those properties in an amplifier. Bear in mind that I like the 150A more than the $2,800 OCM-500. The OCM amp sounds darker, slower, less dynamic, less tuneful in the bass, and has less bass impact. The OCM-500 will drive nasty speaker loads better, but I don't need that with the Vandersteen 3A speakers. You're going to have to get into expensive amp territory before you are going to find substantive improvements in those tricky areas of amplifier performance. This puts the performance of the $1,195 Belles 150A in a very special light. It is not the best amp in the world. But it is so good that finding an amplifier more satisfying will cost multiples of the Belles 150A's price.

You Want MORE?

Lower cost components often respond to tweaks to a greater degree than expensive products do. This was true for the 150A. Selection of interconnects and speaker cables will affect what you hear from this amp to a significant degree. The interconnects and speaker cables I tried with this amp changed things a lot. Two combinations I tried shrunk the soundstage and flattened depth to an alarming degree. The combination that maximized my appreciation for the Belles 150A was Cardas Cross interconnect with Cardas Cross speaker cable. This combination produced a very wide and deep soundstage without exaggerating the midrange. Dynamics remained excellent and musicality was best with this combination. Unfortunately for budget audiophiles, a pair of 8' Cross bi-wire speaker cables and a pair of 1 meter Cross interconnects total more than the cost of the 150A amplifier. I'll keep looking for less expensive interconnect and speaker cable combinations that I can recommend for the 150A and tell you about them in a follow-up. (Manufacturers, if you think you have a contender, please send EMAIL to

The Belles 150A responded very well to the "poor man's" isolation and damping system (inner tube, mdf shelf, zip lock baggies filled with sand under the amp, zip lock baggies filled with sand on top of the amp). Even better was the Bright Star Audio Air Mass (air bladder isolation device) and Big Rock (sand filled damping device) pair under the amp with the Bright Star Little Rock on top of the amp. The feet the amp sits on to couple it to the isolation base also make a difference, the "winners" in this case were 3 medium Whatchamacallit lead shot/silicone-glass-sealer feet. Right now the following isolation/damping setup is being used. It may or may not be optimum for the 150A, I'm still experimenting.

Bright Star Little Rock
3 medium and 2 small Whatchamacallits (on each heat sink assy)
sandwich-size zip lock baggie filled with sand (on the center of the top cover)
Belles 150A
3 Whatchamacallit feet
Rosinante Dark Matter amp shelf
Bright Star Air Mass
Custom Michael Green amp stand with brass bottom cones

Getting the heat sinks properly damped is one of the keys to getting the most sophisticated sound quality from the 150A.

All of this attention to isolation and damping may seem rather gross. But if I've learned anything over the last 2 years, it's that isolation and damping of a component are more important than selection of wires. Probably as important as the selection of the component itself! The attention I've paid to isolation and damping of the Belles 150A has changed its performance from "best in class" to "challenging the best." This is not an insignificant change/improvement. Many components will improve by similar degrees. For an investment of hundreds of dollars in commercial isolation/damping products you can improve a component so much that you'd have to spend thousands of dollars on a better component to achieve a similar improvement in sound quality. If you are thinking about spending thousands of dollars upgrading a CD player to separate transport and DAC or upgrading your turntable or preamp or amp -- give some serious consideration to isolation and damping devices for much less money. You will be amazed at the upgrade in sound quality you'll get. You can try the "poor mans" route for about $15 per component just to get a taste of what isolation and damping can achieve. Then you can graduate some of the more effective commercial products.

And Still More...

If having a great sounding $1,195 100 watt stereo amplifier is only about 2/3 of what you need, how about a $1,495 Belles 150A 3-Channel amp? This amp uses the same chassis and the same circuits as the stereo 150A. You get 3 channels at 100 watts into 8 ohms (175 watts into 4 ohms). The third heat sink fills the center of the back panel of the amp. A 3rd set of binding posts and a 3rd RCA input fill out the last of the available space on the back panel. No underpowered center channel speaker ever sounded good. Having some guts to drive the center speaker is really a necessity for good home theater sound. A stereo 150A and a 3 channel 150A would make for a great surround amplification system.

Wrap It Up, I'll Take It

The 150A is an exceptional value in amplification. For $1,195 you get a very musical, exciting, involving amplifier. It plays all types of music convincingly and enjoyably. This is not a hyper-audiophile product. It is an honest amp destined to be a classic product like the Belles 150 of the late 1980s. If you are thinking about a complete high-end system, the 150A is so good that you could cut your amp budget and spend more on speakers. If you have a good set of speakers and a good preamp but your system just isn't musically "alive", the 150A could be the antidote. Selection of the right interconnects and speaker cables is critical with this amp, its character will change significantly depending on how the wires work with it. Isolation and damping will extend the performance of this amp to an alarming degree, boosting its performance into very exclusive territory. If you're looking for a $1,200 amp, you should be very very happy about the appearance of the Belles 150A. Your amp dollars can now get you sound quality not previously possible at this price point.

...Doug Blackburn

[REVIEW FOLLOWUP]I promised I would keep looking for more cost effective interconnects and speaker cables. It's only been 1 week since I wrote the Belles 150A review and already I have found a really good sounding combination I would not have expected:

I don't have precise retail prices on hand as this is written, but a quick "web check" shows one dealer selling an 8' bi-wire pair of Silver Sonic speaker cable for $169. The XLO/VDO line is generally quite cost effective, something like $75 for a 1 meter pair, though I could not find a specific reference to the retail price.

You might expect to lose a lot of performance at this much lower price point, but I was consistently surprised and pleased with the sound of this combination. While it isn't beating the expensive Cardas Cross speaker cable and interconnect, it is certainly not any kind of "penalty box". You get: great soundstage size - width, depth and height; very surprising detail; a real nice sense of air and space; and rich harmonic content. Not what you always get with budget wires. This is just the start. I hope to listen to the DH Labs Silver Sonic BL-1 interconnect with the Belles 150A along with others. Watch for reports here....Doug Blackburn

Belles 150A Stereo Amplifier
Price: $1,195 USD

3 Channel Version: $1,495 USD

Power Modules, Inc.
479 East St.
Pittsford, NY

Dealer info:
Phone: 716-586-0740
Fax: 716-586-4203