DO NEW POWER AMPLIFIERS USE NEW TECHNOLOGY ? KRELL / JEFF ROWLAND 

Krell, one of the all time classic amps, and built to sustain nuclear war of some kind. If only I could pick the thing up without needing two people.

The nerd in me loves these equipment dissections. Thanks for taking the time to open the Krell and Rowland up… And thank you to your back… those amps aren’t light😅

I just acquired a Mark Levinson No. 332. It really does sound phenomenal and I totally agree on the value of these 30 year old class A amps!

I own an hold Hafler DH200 which always sounded great. It is over 40 years old and needed some parts replacements which had those beer can sized capacitors. i had a great local tech replace the old parts with new being the same parts but new. He updated the inputs and speaker outs, and updated the power cord to a nice IEC connection with a new fuse link and power switch. Sounds great. Never getting rid of it. Considering the Jeff Rowland Amps in the new HT/Media room for my stereo side.

In the early 90s when digital first came out, something changed in the amplifier industry. Amplifiers at the local hifi shop went from 30-40lb Pioneer to 6lb JVC, Kenwood, Sony etc. They would rate these amps at 100 watts x 5 channels (dolby 5.1 was all there was for a time) and maybe put out 20 watts a channel in reality. I remember taking one back and saying "it doesnt put out any bass!?" and he said "would you like to buy a subwoofer". Thats when I knew the market was rigged and I got out of it. Its been a comfort? relief? or something like that finding OCD, someone that recognizes real quality and isnt afraid to call bullshit on the mass produced crap. I remember seeing a Jeff Rowland amp in a mag 20-30 years ago and instantly thought, Now thats the real shit! Wishing I would own one, one day. When Mikey rolled out that 625.... I was hooked..... again lol.

Hi Mike, I totally loved this video you made regarding Amps. Really educational for someone starting their journey and that with a few right choices you can build a killer system for not much money. Thanks Mike 👌

I used a Jeff Rowland model 1 for almost 30 years. It finally has to be sent back to Jeff for service....incredible value and still great sound. I own his original Concentra and 102 amps as well. Been a fan of his unique designs, innovations and quality all my life. Other amps have come and gone. Rowland stays for life

I see JR units are using a highly efficient PWM PSU, but that inherently is more noisy then the old huge transformers. The new IC's, like GaN, used to amplify are made to switch very effectively in the digital domain, so unlike old transistors, cannot linearly amplify analogue directly. It is this inherent trait of switching that makes noise, but then allows us to be VERY efficient, which is GREAT as well. This is why Class D amps are 90% efficient. You have to be badly inefficient to analogue amplify with Class A, or AB. The old tech, is actually better for pure analogue amplification because you could feed in a wider voltage 0-5V. If you took a GanFET, moved it into a class A amp, your input would be maxed at 0.9V in the same setup, making it useless, and touchy to interferences. There really is no better way to amplify direct analogue then to use a tube, or old transistors that perform like crap as a digital transistor. LOL

Krell is where my chronic audiophilia started. The mere word makes feel excited.

In the early 2000s I had the Krell MDA 500 mono blocks. They sounded really good but got THAT hot (class A) that literally after five minutes after switch ing on you couldn’t put your hand on top of it any more. You couldn’t use these amps in summertime as it would heat up the room to a degree uncomfortable. And I felt that this heat would dry out the capacitors sooner or later. So I sold them for more than I paid for and got into Nelson Pass‘s „territory“ (PASS X 600 monos) which don‘t run nearly as hot as the old Krell‘s and even sound much better. I still own and love them dearly!

JR Amps are high end stuff. Lundahl is so good. Using them for my MC Cartridge. Quality!

My favourite OCD video. Im facing the oppertunity to buy a new Rega IO or a used Krell Kav 300i. Ive listened to demos via, shockingly YT, my ears want and love Krell. Inflation adjustment and accountant talk I dont care. Krell it is.

I’d love to see a video like this on the old Adcom GFA555 Mark one

Hitting on my style again Mikey. I do love the bleeding edge but the best trailing edge of yesteryear for relative peanuts turns my crank all the same.

I have 3 Krell’s of this Era! They are AWESOME!! Heavy and built like a Tank!! I just sent 2 of them for a Re-Cap job.

Really enjoy your videos that involve gear from the 90s. As a millennial, I was one of the few that was into HiFi, and looking back I think that the 90's was the golden era for HiFi (lots of competition, growth and passion for innovation). One positive, I'm now able to buy my dream components from back then. 🙂 The only challenge is finding a skilled technician to service this gear.

Nice presentation Mikey! I agree with Mr. Flintstone - please give more detailed definitions of Class A, AB, D etc, and cover the strength and drawbacks of each. Then, for example, there are also differences between regular Class D and GAN Class D. You could even get more specific as to why you stay away from products made in certain countries.

Ive got a Naim System with dual monoblocks, but i'd love to get a 19" rack mount tank like this for fun. Maybe I'll have to save some money and build a muscle system for laughs. Krell, Classe and Bryston are amazing value.

I now know that you are far beyond the Krell Mystic. But I am still having beautiful memories of how Krell crushed everything I was in to at the time. New comer, KSA 250 Used. oh yeah! Thiel CS7 .

That krell today would cost alot more to make than what it cost back in the day lol that's for sure Great video! 👍

The Krell was indeed built like a brick SHouse! Thanks for opening one up.

nice ive got a pair the Krell mda 300 monos i love em

That Krell amp isn't going to last long in your inventory! I have a feeling It's gonna be out the door soon Mikey! What a great value for a Tribe member!

Never did like the sound of Krell. In fact they are what sold me Rotel. The krell was hooked up to a maggie 3.6. The sound was flat. The soul of the music was missing. The speakers were then hooked up to a Rotel, and it was magical. Life and rhythm was restored.

Old Krell is great stuff I wish i had one of those!

brilliant, insightful vid into amp tech....one of your best...

Dear Mike That was wonderful and nostalgic. My first baddass amp was the Krell KSA 250. What a beast. Fast forward to now. Help me find a set of now discontinued Jeff Rowland 735 mono-blocks. Perhaps you have an old customer looking to make a change? Love you!

I saw the tile of this video and the FIRST thing I thought was: OF COURSE NOT! I think,of all the commentators on the internet you are the most competent Sir.I really do but take care not to belabour an obvious point.

I still have a pair of the Krell MDA300 monobloks. 300W Class A space heaters. Original owner from 1990. $10 000 a pair MSRP back in the day. When I turn them on the utility meter spins like crazy and the room lights dim momentarily. Grip the ATC100s like a bastard with speed in the note attack and slam in the bass. Glorious even if a little bit grainy sounding. Image like a champ. Never runout of steam; they keep on giving. I had to upgrade my mains to 20amps. I contend that Krell haven't topped these today. The only amp I desired more were the even heftier Krell MDA500 monobloks. Two pairs of MDA300s for a biwired set-up would be my own private paradise. The only other amp at that time I lusted after were the Audio Research Classic 150s, Harry Pearson's favourite, other than his Jadis JA500s with the JP-1 preamp. Glorious days. Highend hifi has gone to shit nowadays. Look for gear made in the late 80s to early 90s. Get them recapped, if necessary. They are the best bang for the modern buck. The only thing that has changed about Highend hifi is the ginormous price tags and silly man-child industrial designs. I don't want my amp to look like a Lamborghini. Just make it solid and sturdy ike the Krell , ARC, Conrad-Johnson, Mark Levinson, Cello Performance, Jeff Rowland, Convergent Audio Tech of days of yore. PS The Krell KSA150 inyour video was about $6495, and the Krell KSA250 was $8495 in their day, if memory serves. My MDA300s were a monoblok version of the KSA150.

I completely agree with you, but I would push back slightly on one thing. An brand new amp that is of equivalent design could have smaller filter caps but they are still .44F. Material science has advanced like everything else in the last 30 years and so the caps made today are smaller with the same specs. Do they even make caps that big (physically) anymore? Maybe someone does but it would be for appearances if you are repairing an older amp like this. I don't know. Looks fucking cool though.

I had the ksa 150. Kbl. Gorgeous stuff

Great video. It was very informative.

Great video Mikey I am a huge Krell lover from the day I have many,many Krell amps a FPB 750 MCX monos times two pairs FPB 450 MCX times two pairs FPB 700CX FPB 600C FPB300 C I have a few more but you get my point and they all have been taken care of by Krell I have the front end very similar to yours I have the Martin Logan statement Evo2’s speaker system which is quad amped if you want to know exactly the descriptions of my system comment on my response and I will let you know in more detailhave a great day😊

I used to work for a hi-fi retailer, Pacific Stereo, as a tech. Never on a Krell but Bose had a monster like that and of course there was Phase Linear. But Infinity had the first digital power amp. It must have been $5,000 or more. I told the sales rep at the CES show that the price was ridiculous. He said that they would not be able to keep them in stock. But digital amps should be cheaper than analog since the 90s. I'm not in hi-fi professionally anymore. It is not as interesting as it was Listening to the music and listening to the sound of the music are two different states of mind.

Fun. Educational too! Thanks!

Great vid. SMPS's seem to have come of age ahead of class D amp stages, being increasingly accepted by class AB diehard brands - Linn/Graham Slee

But how does it sound?

Thoughts on Parasound? I've owned some for decades, and the new ones still seem to be reasonably well built (without a lot of hype), especially the higher-end Halo items that John Curl contributes to.

Nice presentation. At some point you might want to explain the details of what makes a 'class A', 'class AB', 'class C', and 'class D' amp for those who don't know what those terms actually mean.

I have just sold my Krell amps and want the JR625 s2. If only i had £10k!

Love this passion!!!

Hi Mikey. Great comparison of these two, really shows what`s it all about. Innovation is key. I know because i have to. Besides, maybe you could do an episode about the so called british hifi. I mean the ridiculous overpriced low quality shoe box design speakers and technology out of the dark ages. Sold for high end prices with very aggressive marketing. It would be fun.

Look at the power choke system on the Schiit Tyr amp it’s neet

Love this videos

Hi, what about the theory of high backing a small capacitor to the large capacitor that is supposed to release a quicker initial energy release for Better Sound that Paul of PS Audio discussed in one of his videos that amp engineer demonstrated to him at one time ?

And that's why I buy mostly second hand gear. Buy cheap, refurbish where needed, have something far below cost of the modern equivalent

Awesome vid! I love neo-vintage gear, my power amp (Levinson) and preamp (BAT) are 20+ yrs old. Superlative performance at a mere fraction of the cost of new.

Great video!

So.... When will we get some opinions on Pass Labs, as in... 2022?

But how do they compare sound wise?

ΤPA3255 is the sort term future. Next, are coming new IC that amplify direct digital signal from digital source, with a dac at output. This is the future, digital source, digital amplification, hi voltage and current conversion to analogue for speakers. If someone believes the opposite, is Romantic. And technology don't care for this. I say this, that own 10 A and Ab class amplifiers with transistors and tubes

120 watt set? Try one of the 833 Amps? They get up there too. NAT is nice too, though. All way over budget for me sadly

a fun honest review

THE TRUTH ALWAYS COMES OUT.

A bunch of smaller capacitors have much less actual farad value than what they add up to due to clamping current phenomenon. Those big ass caps are the way to go for sure.

I knew this was coming...😁

I see 8 pin op-amps in the Rowland, are these in the signal path, or are they servo's for nulling the output offset? A Switching power supply is bold, but most people think linear supplies sound better. Maybe this Rowland is the ticket to great sound.

Piggy backing a small capacitor to the large capacitor . Any thoughts on this ?

It requires a minimum of 45amps of power to Arc Weld with 3/32" 6010 welding rod! It's not recommended to weld with Krells, but certain models will get the job done! Don't ask me how I know! 🙊🙈🙉✌️

From the days that most were build in the US.

Because it's at least 30 years old would it require new caps?

Mike,what do you think of Sanders and Coda amplifiers for Magnepans speakers?

Hi, so what are the sound quality differences of the Jeff Rowland amp to the older Krell amp ?

I’ve thought about getting mark levinson 33x series amps for a thiel cs7 thoughts? They go down to 2 ohms at certain points

I’ve seen some class A amps ,including Krell , using a sliding bias. I noticed that they don’t have the huge fins. Any thoughts on these? Are they as good? Thanks

Do you think the jeff rolland stuff beats the best from the 80s and 90s? think of accuphase m100 or sansui b2301 and so on?

Mikey what are your thoughts on the technology in the Aavik amps ? .. tesla coils? & the I-580 has a solid copper inner chasis ? High end by oz won't be carrying borresen or aavik anymore , don't know who will. Lots of discounts on them right now.

Give me the Krell with its linear PSU and non - Darlington output devices any day. The data sheet for output devices used in the more modern amplifier doesn't show the ft for STD03P and STD03N, Darlingtons are known to have a poor performance at high frequencies and IMO as an amplifier builder, the designer took the easy route when he designed the output stage. There are also op amps used in the design, I only hope they're not in the audio path.

So how does the old Krell sound? That is the only thing that matters.

Rowland amps are interesting, but its lie to say there’s any new technology in there. A different design approach maybe, but putting in a switching power supply instead of a linear one, and transformer balanced design is not new at all.

Were are the transistors made?????.Japan??? Toshiba????

Old school rocks

Way back in the early 90's I had the Threshold Class A stasis amp. It was a monster. Sounded awesome. Luckily the room was my basement very large like 20 by 30 feet long or something. That thing threw off serious heat! Now way you can put true class A in smaller rooms it is unbearable almost.

That's a great video (and one of your least rambling), and I agree wholeheartedly, except it's incorrect information to say the NATs are the only SET amps that deliver this kind of power. There are probably quite a few, maybe the greatest I could think of Amplifon from Poland: their SET42 use GM70, the SET140 mono blocks use 833 DHT tubes - I like the fact that the product "name" simply indicates the respective output wattage (needless to say, 833 will barely break a sweat putting out 140 Watts). Awesome products, all built in house machining on a CNC machine the guy designed and built himself, output transformers wound and encapsulated in house etc. & etc. Just saying, it's one thing to promote "your" products (that's fine), but another to claim they're the only ones at anything (with the exception of AGD, those are indeed unique, at least to my knowledge).

The efficiency is to low. A switch mode amp will get you more power from a typical wall outlet.

An amplifier as a concept is simple but Krell Amps are anything but simple, they use incredibly sophisticated circuitry. Tube Amps, and some of Nelson Pass's Amps are fairly simple but Krell Amps are not.

I enjoy my JRDG Continuum S2 enough that my much more expensive tube gear just sits and collects dust.

Carver used to design transformerless amps with a switching supply in the late 1970's , doesn't sound like new technology to me , maybe more refined but not new tech.

Where do you sell these equipment?

good video, what's your feedback on the Jeff Rowland Capri S2 preamplifier

WOW

Those filter caps are the size of beer cans

Playback Designs, Play Back Designs, Play Backdesigns.

Ah Jibbiddy jabbiddy Ah ratt-AH-Tatt-Tatt... I'll take Charlie Weaver to Block.

OCD Mike, ur one of the few high end audio dealers or selling snake 🐍 oil and BS. You need to get your hands on some Perlisten and tell me if that’s BS or not. We need more things that are the real deal

Why did they put the Gaan components inside a tube looking component? Is it just for cosmetic purposes?

I want! The thirst THE THIRST!

Well hears my in put yes my amps pull 12amp a pice when pushed they will kick the breaker.cant change the breaker it not mine but back to the point on the krell you need a power station to feed it like my amps ya they sound great but they heat up your room now you need air conditioner etc... Is it worth it he'll ya but they get old they need up grades so what really matters your option or the fact or dose it matter at all. One thing I will say is down low ie volume those heavy hitters don't lack a bit but so dose a digital amps do the same thing with a different sound and you don't have to be a body builder either.or should we buy Elon musk's new amp it's got a nuclear fusion ic chips made from space age ploymers and transformers from his space x ships that all where rejected from NASA. But what sounds good to you. The beast or the burden.peace.......and the fun begins..hifi ya

The price is too much. The parts inside that thing don't cost that much.

its digital chips inside a tube ... purely a gimmick with no engineering purpose ...

This total BS. You absolutely find all of those things in contemporary gear that is a cost-for-cost parallel to something like this Krell. Why do all vintage people compare old top of the line to new gear that's a fraction of the adjusted for inflation cost?

Dude adcom b&k Aragon acurus and others used these big blue caps too but I'm sure companies like ATI outlaw and emotiva know what they are doing too with multiple smaller caps per board.

great video!

I think you are a bit biased too

Is the Krell KSA150 the one that Krell intended specifically to drive the 1 Ohm Apogees?