Yamaha B-2 Amp

Yamaha B-2 VFET Amp Refurb

EW just let me know that he has finished with the refurb of the first of the B-2 amps I dropped with him earlier this summer . Here is the info I received from him about it's performance:

"Finishing up the first one. The power supply has been totally recapped, and the driver boards only have one lone electrolytic which was also replaced (along with the trimpot swap), so the only thing not recapped is the meter circuitry, which of course would not have any effect on sound quality anyway. The opposed electrolytics at the input have been replaced with four 4.7µf non-polar Blackgate caps (one per channel).

I ran the amp through its paces. The amp clipped at 160WPC @ 1KHz, and at 100WPC, distortion was at about my measurement limit of 0.003%. I can’t remember when I last measured distortion that low at such a high power level. Pretty impressive.

I ran it at a solid 50W output for 20+ minutes, and it took it that long for the heatsinks to actually get hot. Nice design.

The front panel meter assembly is likely the most accurate I’ve ever seen. Most meters are not much more than eye candy, but Yamaha built this assembly with the precision of an electronic instrument. Seems to me a lot of trouble to go to, but nevertheless they are dead-nuts accurate at about any level you care to run ‘em at.

I haven’t had a chance to really listen to it much as of yet, but will be running it in the background for the next few days. First impressions are consistent with my measurements...clean and open, very natural and unstrained."

It sounded very good before I dropped off for the recap, etc., so am looking forward to getting it back and seeing how it sounds with the recap, etc. Just needed that 'every-25-year-going-over'. At 57 pounds, the only heavier amps I know of on a watt-per-pound basis are all class A. Should be fun.

As always, Thanks, EW!!

Here's a pic of one of the B-2s when I was using a CX-1000 preamp.

I bet you're a bit antsy to get that amp back from EW, I know I would be!

Indeed. The one EW is now working on has a burned relay so waiting for parts. And he has another three receivers of my brother's we hope he gets to so can make one run to KC to get everything at once. Should be a 'banging' system. Set of NS-1000M's running on one of the B-2s and the set of NS-500M's running on the other. Maybe I'll set up the other B-2s and get a 7.1 decoder and do the HT thing. Time will tell.

For its entry into "serious" audio (or "higher-end" at any rate) Yamaha made statement units and, besides Accuphase, I don't know of any others that stood the test of time so well, in a truly undisputed oecumenical-all-together-now fashion: these are among the very best, top of the pops and crème de la crème: NS-1000, B-1, B-2.

Second B-2 is done...new relays came in on Sat, but I had Grumpy's BA-5000 on the bench, so it waited till today.

Only got about 150WPC at clipping out of this one, but easily could be accounted for by line voltage fluctuation (AC on and everything). Distortion still just barely measurable at 0.0038%.

Lookin' good. :thmbsp:

Just got in from Axel's land to a minor flood in the basement. Think my daughter was down and somehow jammed the ice-maker in the frig. Thankfully it was only yesterday, so should be a quick recovery. Only real damage was to the nice set of EPI-120b speakers that merrylander had redone. Sitting on the floor and got wet enough to lift the veneer. Will have to wait until they dry out to see if the damage to the MDF is terminal.

Glenn,

Did you get a nice weather where you were? Not too many arrogant frogs around?

Excellent weather, excepting rain on our trip down from CDG to St. Emilion. Partly cloudy or sunny every day with highs in the low-to-mid 20's. Excellent wines, but average food in the Bordeaux region (except the oysters, which, of course, come from Brittany this time of year). Looking (tasting) at wines in the region became a chore. Business must be way down as the shop/vinyards were really pushing their wines. The real 'hard sell'. So much so that we felt put upon by the sellers and learned to avoid a couple of shops near our hotel and bought from others. Attached a pic of us at the highest point in town (excepting the bell-tower) looking north into the surrounding vinyards.

Warmer in the Loire region and Paris, in the high 20's to low 30's. But, the food is much better than around Bordeaux. And our friends have a nice house dating from the 1500s adjacent to the main chateaux in Thouars. Their back yard runs down to the Thouit river, so was nice. Other than the 5'5" doorways. But, of course, nothing can compare to the 'City of Lights'.

As always, one of the highlights of our visits is the music in Notre Dame. The singing and organ in vespres and high mass is just magic. If my home system could ever sound so good I would have all that I need.

Yippee!! Two large boxes on my patio when I got home today. Could only be the pair of B-2s that EW went through for me. Extremely well packed. After getting two 60 pound boxes of amps into the basement I am rewarded with that wonderful VFET sound. First up is Dire Straits "Brothers In Arms" on vinyl. Superb sound. Gotta get that kitchen finished so can get the listening room finished. Wife will only put up so much on this. But....getting close.

Thanks, EW. Terrific sound!!

I've got the newer, mid-80s TOTL M-80, a 250 wpc piece of work. By the time it came out the technics for making excellent solid state amps was in place. Thanks to the receivers watt war, solid state design matured quickly. My M-70, TOTL in 1984, is another fine amp using the X power supply and X amp circuitry.
I think everyone should know that I love Yamaha gear. Brutal yet sweet. Just damn fine sound that can take you away from your worries.

Strange things afoot with my Yamaha C2x preamp.

I have been using a Kenwood C2 as my phono preamp for the last 4 or 5 months.Last night I reconnected my Yamaha C2x into the system.Before I did I took the bottom off it just to have a look inside,as I had seen many photos of the C2x's innards but had never had mine opened.
Well,it is stated by those who know more about Yamaha products than me,that the C2x was/is a completely different beast to the previous 2 Yamaha preamps which bore the family name C2 or C2a.You really should see the insides of one of these things(sorry I don't have a digital camera).It's full of really high quality components(Black Gates,Nichicons,Alps blue pots for the tone controls etc).Totally different to the C2 or C2a.I was duly impressed :yes:
I put it into the system,reserving any judgement until I'd given it time to warm-up.This preamp has a couple of strange operational quirks/features(?).I use mine as a phono preamp only,taking the signal from the "tape-out"sockets to my Kenwood 700C.This bypasses all the front panel controls other than "selector" "record-out" and the phono selectors.No volume control,tone controls,filters,balance...nothing.So anyway,using it like this,you can turn the power OFF at the front panel switch and it cuts out,only to ramp-up again after about 90 seconds to two minutes.After which time it continues to operate much the same as it did before being turned off :worried: Don't ask me what's going on here, I have no idea.I just discovered this by accident a coupla years ago.
It sounds different this way;darker sounding with a bit of softening of transients.I decided I didn't like it like that,so I switched back to power ON.
Then I remembered that there was another unusual thing.Next to the volume control/balance knob there is a muting switch.I had previously noticed that inbetween the two mute settings was a spot where the sound changes.So I tried that.
When this"spot" on the muting switch is found the input selector sounds very different depending on whether you have it switched to "phono" or whether you have it switched to one of the other inputs(irrespective of whether they are used or not).There is also an increase in gain,so I'm not just imagining this.I MUCH prefer it swiched to one of the other inputs.The difference is not subtle,and results in a marked increase in the amount of musically siginificant information coming through the preamp.
Used this way the C2x is just amazing.
Would anybody be able to tell me just what's going on here.(If this post gets bumped off this thread I'll understand,it's just that I discovered this last night,and saw this Yamaha thread today)
I'll agree with what Axel said,Yamaha made some gear upon which they we were staking a move into the high-end and most of this stuff other than the NS-1000s,is completely unknown by the audio-loving public in general. :scratch2:

As I've mentioned to you before, the only cure for your C-2x problems are to send it directly to me for interaction with the B-2 amps it was intended for. While I am told that occasionally one comes up for sale in the U.S., I've only seen one in several years of looking. I'll trade you a nice phono stage directly across for your preamp. And, those niggling little problems/quirks will not bother me one bit.

But, seriously, without the schematic and some time and the unit to play with it would be difficult to do anything but guess on what is happening. Sounds like it might be some capacitive coupling or high resistance short due to crud produced by the switches during normal operation. But only a SWAG.

From Box to Life!

Here are pic's of EW's great packing work and the first B-2 returned to its rightful place in my main rig.

Sorry the C2x ain't going anywhere soon!

B2,
I also look on the net for more onfo on the C2x and find that it's a unit which is thin on the ground.When I do a Google search I find most of my own posts on web forums concerning this amp are the ones displayed! :worried:
I'm mighty glad I bought it when I did.My inspection of the insides of the unit confirm that even though I paid around $350 US for the unit,I still got good value. :yes:
I'd like to hear the C2x/B2 combination.I feel that the Kenwood 700C is the better of the two by far. :thmbsp:

See - just another reason to send that C-2X over to me.

But, seriously. My guess is that there is something wrong with it somewhere that is resulting in its lack of good sound. Another thing might be the synergies between the KW preamp and amps. Something that might just not be there for the Yamaha/KW combo.

I doubt there's anything wrong.

I merely think that the Kenwood 700C is the better of the two for line level duties.The Yamaha however has the better phono stage and is moving coil capable,which the 700C isn't.
I'm happy to own both.The 700C is a good enough component to base an entire system around.I'm not Yamaha-bashing when I say that,I wouldn't part with my Yamaha PX-2 even if I could somehow afford a better turntable.The PX-2 is in my experience foolproof,as convenient as CD and sounds amazing.
It is a technological tour de force and an equivalent in todays money would cost at least $10grand US.This has to be one of those units which Yamaha lost money on.

There are certain elements of my system which are crucial to it sounding as good as I know it does.The tuntable,phono preamp,preamp and speakers are irreplaceable.They are all VERY VERY hard to find here in Australia, and I am pleased to own every one of them,they more than live up to their well earned reputations. :yes:

The B-2 has come into its own. The bass is considerably tighter than it was prior to being recapped and the piano is almost as if it was sitting in front of me. I am amazed at how good the sound has become from these 25+ year-old amps driving a pair of 20-odd year-old speakers. Maybe I'll rent a room at the next NYC HiFi show and see what others think and how it stands up to new systems (all I need is for someone to give me the $25K that would take).

Just dawned on me one of the reasons that the sound is so good. The background is absolutely dead quiet. Guess that is what EW was alluding to when he stated that the distortion was at the limit of his ability to measure at full power (<0.003%). While I am sure that is not the only reason, tis one quiet amp. Nothing but the music. Mark Knopfler is 'Sailing to Philadelphia'. Beautiful.

Duh! Quiet is S/N. not distortion. Been a long, hot week without AC.

My measurements are THD+N (total harmonic distortion + noise). Most analysers (including mine) cannot distinguish between noise in the output signal and a deviation in the output sine wave from harmonic distortion...basically anything that is not supposed to be there is lumped into the category of 'THD+N', so yes, noise definitely affects this figure.

Yamaha B-2 said:

Maybe I'll rent a room at the next NYC HiFi show and see what others think and how it stands up to new systems

Click to expand...

yes! do this! only hide the gear behind a curtain, the NS behind a thin backlit veil and let them wonder what NEW equipment produces such gloriously magnificent sound!
(Wow! it must be the new XY amp (25k$ w/out options) - such bass definition!! such clarity!! quelle élegance!!)

Discrimination is it's own reward.

B2,
You've had the guts to go against the tide of lemming-like behaviour and give a 24 year old component a chance to speak for itself.Therefore you have found that is a very eloquent arguer for the quality inherent in many overlooked vintage pieces. :yes:
Your deviation fron the herd has been a reward in itself.Now,please sit back and enjoy the fruits of your efforts. :thmbsp:
Thank you for sharing your journey with us.