Yamaha VFET vs. Sony VFET

Yamaha B-2

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Have started doing the listening comparison between the newly arrived Sony TA-5650 (50wpc) and my standard, the Yamaha B-2 (100wpc) with CX-1 preamp.

Just based on the relative weights of the these systems (26 pounds for the Sony and 76 pounds for the combined Yamaha B-2 + CX-1) you might guess what some of my listening is telling me.

Am driving both into a set of Yamaha NS-1000M speakers that have been upgraded with DHLabs 14ga wire and Cardas speaker terminals.

First listening impressions are that there is 'more' there with the B-2. Easier sound, bit more solid in the mid & bass regions. Dare I say it? Weightier? But, the Sony may be just the most musical amp I've ever listened to. It simply gets it right. Have done about three hours of listening thus far, all on classical. But the Sony is simply very, very musical. Very involving. Pulls one into the music, if you know what I am saying.

I need a couple of weeks of listening to be sure, and will post an edit once I get there. Lots of jazz and classic rock to run through the system, yet. Has only been our great local FM station (WRTI, 90.1) thus far. Vinyl and CD/SACD to follow. Ah...the strings are singing on Vivaldi. :thmbsp:

Any other VFETers wishing to add their experiences and comparisons are welcome to post on this thread.

Also, check this thread for additon VFET info and links: http://audiokarma.org/forums/showthread.php?t=31881

More later.
 
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I owned the 100w/p/c 8550, and the same could be said for it. Nice, but not particularly dynamic.
 
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Interesting but a bit brief. I'm looking forward for the continue to your revieuw!
The Yamaha [B-1] is one of my favorite piece of electronic all time. It's very very dymanic and fantastically clear. Needs to be coupled to an equally excellent pre-amp to preserve its quality though.
 
A bit more. With continued listening I find that the TA-5650 is just that bit more 'musical' than my B-2/CX-1 rig. That is, the music sounds just that little more 'live'. Such an easy sound to listen to. However, it has what I will call a 'flatter' soundstage. While expansive from left to right. It is not as deep from front to back. And just a tad of the solidity of the sound in the lower octaves is missing. I am sure this last could be touched up with the selectable tone controls on the TA-5650, but I listen to the B-2/CX-1 rig in the 'direct' mode with tone controls out of the circuit.

Am finding that the Yamaha is starting to eke ahead just a little, in my preference. This may do be due to the fact that I am doing quite a lot of ochestral music listening and that extra heft provided by twice the power is providing better support for the full range of this type of music. Will do some more jazz and classic rock over the weekend and see how it goes.

Also, haven't done any vinyl to speak of on the TA-5650, so will do some of that this weekend, as well.

More later.
 
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That was interesting. And sorry if I sounded like commanding you on my previous post, I need to be more tactfull.

I also listen to alot of orchestral music, and the B-1 is excells at it!
 
Was involved in the upgrade of a chemical manufacturing plant in Belgium in the early '90s. About 50/50 Flemish and French speaking. Was an interesting mix. Work rules/taxes were quite restrictive by U.S. standards. Couldn't get anyone to work overtime. I did a couple of days before the plant manager told me I couldn't as it was creating problems with the workforce. He didn't elaborate.

I'll post again after some vinyl this weekend. But, I can understand a couple of the posts I've read where folks have preferred the Sony to the Yamaha. It would be easy to go either way. I think I could to with a different set of speakers, such as Soliloquy 5.0s or other very easy to drive units.
 
More listening results/impressions.

While the TA-5650 still sounds wonderfully musical, and I have no complaint about its preamp on all other functions, its weakpoint, for me, is its phono stage. For one thing, I listen to a medium output MC cartridge. So must turn the volume up to 50% to get to even moderate listening levels. While fine, not my preferred listening position on the volume dial (prefer ~25-35%). Experienced no 'noise' added by the preamp. At least nothing that I could identify as noise from the preamp section. But, the music seemed to have that 'vale' over it that I do not care for. Lost its open, musical sound that I was getting from the other inputs. Am not surprised, as this amp was designed and built prior to the advent of the better FET frontends that started becoming available about the time that this amp went out of production. Too bad. Would have solved the problem with the only weak spot I've found. Well, not quite. It doesn't have a remote. Am also guessing that the TA-5650 would benefit greatly from a recap. Especially in the phonostage. Really a delightful integrated amp, otherwise.
 
Very interesting to read -keep the review flowing!

Do you think a recap' would be difficult to carry out?
 
Don't know, yet. Have to pull the top off and see where the phono board is located (hopefully it has its own board). If I am going to keep I am sure I will evenutally do so. Once I get there I will let you know.
 
As strange as it may sound, once you figure out the logic, it's not too difficult to work on. And YES it would MOST DEFINITELY benefit from a recap, as well as some other minor changes (different BJTs in the input stage and perhaps preamp). BTW the 5550 power amp had a dual FET input stage, and Sony was one of the first to produce dual FET transistors (even some Sansui AU517 and 717 I've had used a Sony dual FET in the front end of the power amp!), so I think it was just a decision not to use it given the cost bracket (...even though the 5650 was not cheap!).

Let me see if I can help with that 5650... the first picture is a nude of the 5650. There is another board attached to the front panel on the right side, under the one that you can see, IIRC that is where the Phono preamp lives.
The second picture is of a 4650, the preamp stuff, all on the front panel, is quite similar, also the service position of the panels, which the pic illustrates. You can actually lower the front panel until it's in line with the bottom panel, at which point everything is quite accessible. The boards can be dismounted by removing the plugs and unscrewing the screws on the front subpanel (you need to take off all knobs and the actual aluminium panel). On that second picture, the Phono section is the second board from the left, in front of the power amp assembly.
 
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Sony musical? Yep. I'm running a 6060FW receiver in place of my Mc system on my Bozaks and for the first time I've found a piece that does not make me miss the Mc in a short time on them and for long term listening it is not the last word in any particular area but is so very nicely balanced that it just works so well in delivering the music.
 
In the TA-5650, the phono stage consists of a 2SC1636 BJT followed by a 2SK63 FET followed by a 2SK23A FET followed by a 2SA705 BJT, in each channel. No dual FETs.

Rest of the preamp consists of another 2SK23A FET followed by another 2SA705 BJT followed by another 2SK23A FET followed by another 2SK23A FET. Pretty simple and straight forward without a bunch of ICs.

Which of these BJTs (all?) do you recommend changing? And to what?

ilimzn - PM with your e-mail if you would like the manual as an attachment. Is not perfect, but I can read most everything.
 
Yamaha B-2 said:
...Which of these BJTs (all?) do you recommend changing? And to what?

That would be the first one, in the Phono stage. I'll have to look up which one I used, 2SC something as well... brain is not the sharpest at the moment, it's 2 AM here ;) Echowars would know, it's one of his favorite low power BJTs ;)

No need to email the manual, I downloaded it from the site you referenced - thanks for the offer, though. Looking at it right now, actually, even though I should go to bed...

The email, should you need it:
ilimznAThotmailDOTcom
 
Ta5650

I have the Sony TA5650 since 1983 and since a year I built the Transcendentsound.com Grounded Grid Preamp kit (replaced coupling caps with Auricaps). Just unplug the endstage bridge on the 5650 backside, connect the Grouded Grid and that is a WOWOW. Valves and VFET together. The short signal path of the grounded grid and the 5650 endstage does it. Cheers from Holland. Ron. havenaar@signet.nl
 
Hi Ron - welcome to AK. Good to hear from another VFET owner. Sounds like a plan. I'll have to try that with one of my Yamaha preamps.
 
You know, looking at the Phono input on the 5650, I am more than a bit puzzled that they used a BJT at the input and a FET as the output. Given the noise performance of FETs with a high impedance input, i would have expected it to be the otehr way around. I'll have a run of it in a simulator to see if that can be done as a mod...
 
That one is actually not too surprising. With the number of stages they have tere, the open loop gain would probably be too low with just JFETs, assuming you actually had JFETs that could span the required voltage. There would have to be two stages or BJT cascodes, so obviously given a cost vs performance to design for, they chose the lesser evil.

BTW that input stage can benefit greatly from a change in BJTs. In theory, the transistors used should be able to withstand the voltage difference between the two power supplies. If you look the data up for them, they do not. Granted, normally they never see the full difference given the input levels normally found, but at any kind of heavy clipping, or input overload, these BJTs will be operating outside safe limits.
I had two 5650s both of which started life with dead VFETs, and having lost one of the supply rails (fuses) when that appened, was enough to make the input BJTs on both leaky. When I got the 4650, I just changed them without even checking the originals. In addition, most modern BJTs that will fit will also have a higher gain and Ft, resulting in somewhat less overal distortion for the amp. IIRC OnSemi's MPS8599s were the BJT of choice for this. Just keep in mind that the pins need to be bent around as the pinout is different.
 
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