Classic, Cult, Affordable Class A Solid-State Amplifiers: Bedini, Forte, BEL

Classic, Cult and Affordable Summer Amp Shootout- Three of the best solid-state Amps ever made: BEDIN 25/25, FORTE model 4a and the BEL 1001.

As the temperatures have increased, I have found myself moving away from my tube based amplifiers to solid-state to keep the heat down. Recently, Ive had a good bit of luck actually getting my hands on some legendary, hard-to-find, solid-state amplifiers from my past:

Bedini 25/25 class A

Forte model 4a class A with Jon Soderberg mods

Brown Engineering Labs model 1001 mark lV

Let’s start with the Bedini. These products were made by two brothers, John and Gary Bedini, back in the the 70’s. Interesting bit of folk lore about these was that John designed the amps to mimic the waveform of an EL-34 based tube amp, while another is the amp was designed with schematics taken from a DOD tank turret controller. 

My first listening session in 1979 was shocking, a little class A 25/25 was driving a pair of magnepan mg-1’s while being fed by a CJ PV-2a and a magnepan unitrac tonearm with a grace F-9e on an Aristan rd-40. The Bedini was highly biased- somewhere around 135 degrees, sounded FAN-TAS-TIC. Imaging, a Magnepan strongpoint, was so pronounced it was scary. I had to have one, I bought my first one shortly thereafter and have had at least one in my possession ever since. Over the years they have taken on all comers and cemented themselves as my number 1 solid-state amplifier, even though it is approaching 50 years old. Harry Pearson founder of The Absolute Sound said the Bedini 25/25 was THE amp for Quad ESL’s. I think the 10/10, 25/25, 45/45 and 100/100’s all sound very similar (I have a 100/100 also). But the 25 has better signal to noise ratio than all the others. It does 25 watts into 8 ohms and 50 watts into 4 ohms. Unfortunately, the Bedini brothers, John and Gary both passed away on the same day, November 6, 2016. The later units like the DE, BA, BC and especially MKll’s are NOT the same.  

Forte model 4 is another class A design, this time by Michael Bladelius.  Forte was the “value” brand of Threshold. A lot of the Threshold technology (think Nelson Pass) made its way into the Forte line. This unit is the first amp I know of which utilizes the somewhat controversial IGBT output devices. Doesn’t matter what is inside, it’s tone has made it a classic. These also run hot. Mine is currently biased to 133 degrees. The unit I procured has been modified by Jon Soderburg in Citrus Heights. Jon replaced the power caps and some other caps with BlackGates which unfortunately, are no longer available. All units should get his update although BlackGate is out of business. It does 50 class A watts into 8 ohms and 100 watts into 4 ohms. Built like a tank and as opposed to the Bedini and BEL, it uses a toroidal transformer.

The Brown Electronic Labs (BEL) 1001 is a 50 watt no frills rectangular box(y) amp. It does 50 watts 8 ohms, 100 watts into 4 ohms and can run mono-which is supposed to really enhance things - it quadruples the power but on the downside halves the sensitivity.  Somewhat controversial as to whether or not it is class A or sliding A, A/B. Much smaller heatsinks but those small heatsinks get HOT >135 degrees. The BEL was designed and built by Richard Brown in San Jose, Ca. Unfortunately, Richard passed away a few years ago. I ran with a pair of these as monoblocks in the early 90’s powering some first generation VSA VR-4’s. The BEL 1001 amp came in at least 5 versions - I have the mark lV circa 2005. Basic, utilitarian, simple, special and classic.

My current system and biases. I’m a vinyl guy. I think digital playback has made great strides and is incredibly convenient, but comes up short in numerous audible areas against a top vinyl system. Digital has qualities that are more important to others than myself, namely: the convenience and a black background, no hiss, no pops. My digital system consists of a Mac mini with lossless recordings going into a Doge 7 DAC. The Doge offers a 32bit/384kHz chip that is DSD compliant together with a full tube analog output stage. The tubes I run are triple-mica black plate GE’s from the 50’s and 60’s. Then on to my line stage which I will cover shortly. On the vinyl side, I currently run a Benz Micro LP-S, a Monster Sigma Genesis 2000 mkll and a Monster Alpha 2 all on separate VPI JMW 12.6 arm wands. The JMW is mounted on a VPI TNT jr. The turntable is balanced on a Kinetic Systems Vibraplane for isolation. This feeds into an Aesthetix IO signature phono amp with 26 hand-selected tubes. Hiss is a challenge, but I have yet to find anything that comes close. The Aesthetix drives “The Truth” passive linestage with both copper and silver inputs. The truth is a solid state line stage that Arthur Salvatore says: "The Truth" is the most 'perfect' electronic audio device, of any type, that I have ever heard”- enough said. The linestage drives 12-foot Alpha Core Goertz silver sapphire cables to the amps which drive Von Schweikert VR-4 Sr. Mklll speakers isolated on points on top of granite slabs. I use Alpha-Core Goertz wiring throughout. The amps I usually run are Coincident Turbo 28-watt SET integrated amps which I use as just SET amps bypassing their line stage and vertically biamping. I have two VSA subwoofers but have not yet decided on their status.

One benefit of the quarantine, if there can be a benefit to something this devastating, is that I have spent some of my free time every day learning to play the piano. I think this has sharpened my sense of hearing and certainly improved my appreciation of live music as well as confirming I have limited skill as a musician.

For this shoot-out I used a very focused, limited song selection consisting of Paul Simon’s American Dream live, Dusty Springfield’s The Look of Love off of the Casino Royal soundtrack, Gordon Lightfoot’s If You Could Read My Mind and Black Cow by Steely Dan. All of these are great recordings stressing different octaves, instruments and arrangements. Probably the most revealing cut is American Dream’s simplistic guitar arrangement and Paul Simon’s voice recorded live. I can tell so much by how forward or back Simon is, where he is placed on the soundstage, but most of all the tone and plucking of the strings on his guitar. I don’t think I have sensational hearing, but this cut can be incredibly revealing. I have heard the string definition on good amps and bad, tubes and solid state and am now so familiar with what is possible, it is getting to the point that I can really appraise an amp (assuming the rest of the system is mine as outlined above- in my room) via a single listen of this cut.

Also, back once again to the importance of system synergy. Changing one component can SIGNIFICANTLY affect the sound of the system, and it happened here. I listened to all the amps, picked the “winner” and wrote this review. Then, I decided to listen with different cables and I came up with a new current preference, albeit by a hairs breath. This not only shows how close everything was, but how one small change can affect the entire presentation. I left my original writing intact and then added the update at the end.

OK, on with the comparison; first and foremost, I know Icould be happy, long-term, with any of these amplifiers (in fact I have been happy with the Bedini’s for four decades), they are all that good. After warm-up, they are all incredibly musical. The type of musical tone that brings a smile to your face and where you find yourself commenting out loud, although no-one else is in the room. The kind of listening session where you lose track of time, emerging hours after you went in, leaving piles of records on the floor because you keep thinking of new songs you can’t wait to hear.

So, Third place: (The king is dead, long live the king!) The Bedini 25/25. At 46 years old, the design and implementation is still relevant. Not just relevant, competitive. Not just competitive, but really, really musical. Without a direct A/B comparison with the other two contenders I could live happily ever after and confidently sing its praise. PRAT with warmth. Great soundstage and depth. Nuance and heft. But compared directly with the other two amps, just a bit veiled, not as clear or striking but great musical reproduction. The Bedini 25 is the king of the Bedini  line up because it has the best signal to noise ratio of all the Bedini amps.  One small handicap here was the 25 was half the wattage of the other two amps, but it was also twice as sensitive. 

Second place: Forte Model 4a.  Ok, now we can start to get into the meat of the differences. The Forte’s soundstage is a bit narrower than the Bedini, but it is a bit deeper. Neither is a slouch in the soundstage department, painting images well beyond the width of the speakers. Paul Simon is larger with the Forte and slightly forward. The Forte had just a bit more overall heft in comparison to the Bedini but more importantly, it is a touch brighter, no, that’s not quite right, it is a touch more articulate. The Forte is better at isolating each string on Paul Simon’s guitar, while the Bedini presents it more as a whole organic instrument, just a touch less precise. I don’t know if that is due to the wattage difference or not. I dont think so, as I was not playing it at high SPL’s. The Forte shocked me with its delicacy, crispness and immediacy. I would say the Bedini’s presentation of the strings was a bit muddy in comparison, but it is not, it is really, really good. Therefore, I have  to conclude the Forte is just that much better. Clear, crisp, organic, it sounded like he was here- I don’t know what else to say, that is about as high a compliment as I can give to a musical reproduction system.

Winner, Winner, Chicken Dinner: The Brown Electronic Labs (BEL) 1001.  Wow, what a great amp! Not what a great solid-state amp, but what a great amp period. Tom Miiller, a reviewer for The Absolute Sound years ago proposed that this could be the best amplifier ever made.   It out performs my Coincident SET amps in some areas, but also loses to them in many others, the most obvious being the amount of air and space around the players and instruments. But man, is his thing musical! Great, Great tone. It surprised me like the Truth line stage did. In my (biased) mind, based on decades of experience, I believed that the sound I prefer could only be delivered by a tube-based circuit. But just like the Truth, the BEL 1001 MK lV convinced me that I can be happy with an exceptionally well executed sand-based design. The real way I know the BEL won this shootout was that I found myself wanting to listen with it in the lineup, at the expense of the other amplifiers. As I said before, I feel it is bettered by the Coincident 300b/845 tube amp in numerous, but not all measures, but its delivery of feeling, overall, is a great achievement. I preferred it to the Forte in that it was a bit more relaxed, a bit warmer, like what I would expect from a tube amplifier, while still delivering the heft that a sold-state low end for which solid-state is known.  It’s tonality and presentation are enough to qualify it as my “summer amplifier” and if I’m playing highly dynamic music, I probably prefer it to the SET amps.

Well, that was it, except for one thing, I wasn’t done yet. When I had my “Truth” line stage designed, I had some of the inputs wired in silver and some in copper. The Alpha Core Goertz cabling is a novel design that is touted as being nearly distortion free. Unfortunately, they can cause oscillation in some amplifiers and Bridgeport Magnetics recommends the use of a zobel networks to settle things down. Anyway, I was sitting there one day and it struck me that I should use a different cable design and material just to check. So, back came the classic amps and a new pair of interconnects and speaker cables that were not only a different design but copper based as opposed to silver. The cables were Masterbuilt performance series and I ran the interconnects through the copper ports on the Truth as opposed to the silver ports used previously.  The Bel 1001’s, when mated to the Masterbuilt’s, sounded a bit more subdued and dull compared to the Silver Goertz AG-3’s. This is about what I expected as my experience is that silver seems to accentuates treble frequencies and liven things up. So, to be thorough and complete, I hooked up the Forte with the Masterbuilt cables. What I heard more than surprised me. The copper Masterbuilts “livened” up the Forte, and by “livened” I mean it gave the Forte the rare ability to deliver not only tonal accuracy but an exhilarating shared sense of space - really similar to the BEL.  So as they say, “it was on”. Out came the Bel 1001, “the winner” mated with the silver cables vs the Forte with the copper cables. Back and forth I went, and I went, and I went. Simon, Steely Dan, Lightfoot, Springfield, again and again.

It was now insanely close, and I’m not totally sure of myself but I think we may have a new winner: the Forte with the Masterbuilt copper cables. Paul Simon playing American Dream live on the BEL Is incredibly seductive, huge soundstage, deep, tonally exciting but with the Forte and the Masterbuilts, I could have sworn he was just here. (Of course, with the Coincident SET amps, he is still here!) The only way for me to know for sure which one. I prefer is to sit with each configuration for a long-term listen, which is exactly what I intend to do.