vintagejapan Posted February 20, 2016 Posted February 20, 2016 (edited) I am starting this thread to document a complete rebuild of the Yamaha B-2 The parts I used are what I had available, and I did compiled few suggestions from other DIY forums. The Yamaha B-2 is certainly a marvellous piece, and when properly restore will give you years of trouble free delicious music. Match it with a pair of NS-1000 or NS-2000 and you will be in musical bliss. Ok here we go, I will post as I work on this project so may be sometime between posts. Thank you! Edited February 20, 2016 by vintagejapan 6
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 Parts arrived! No skimping, there are more expensive parts you can use if you like to go crazy with the coupling caps!
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 Case prepped and ready to get repainted. 2
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 New power connector. Furutech audio grade.
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 (edited) Starting with the driver board. I always take a picture of it before I start working. Just in case you may need to check things later.. I does help to have the proper tools for this project. A good multimeter, soldering station with a desoldering gun are a good start. Edited February 20, 2016 by vintagejapan
Martykt Posted February 20, 2016 Posted February 20, 2016 Have intrigued me the Japanese V-fet amps. On the must listen to one day list !! 1
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 All the power resistors and fusible resistors will be replaced. you will need 0.5watt metal film of the same value to replace the small fusible and 2X22ohm/2W, 1.2K/2W,2X1K/2W The doble diodes in the pic also need to be replaced by 2 1N4148diodes in series. Follow orientation on the board. I used polypropylene for the film caps, and some AMTrans metalized film, and one Nichicon MUSE Es series for the bipolar cap.
vintagejapan Posted February 20, 2016 Author Posted February 20, 2016 Have intrigued me the Japanese V-fet amps. On the must listen to one day list !! I have gone through a few, currently own a couple of Yamaha B-1's and the B-2. Have not had a chance to listen to others (Sony has some nice V-fets also)There is magic in these amps, no other solid state like em. 3
Martykt Posted February 21, 2016 Posted February 21, 2016 I have gone through a few, currently own a couple of Yamaha B-1's and the B-2. Have not had a chance to listen to others (Sony has some nice V-fets also)There is magic in these amps, no other solid state like em.That's what I've heard about them. The other amp that I'm very curious to hear is the Digital Do Main B-1a amplifier from japan who even apparently make their own V-fet devices. I'll be fascinated to see how your B2 turns out. 2
Rob181 Posted February 21, 2016 Posted February 21, 2016 I'll be fascinated to see how your B2 turns out. Yep...me too... 1
vintagejapan Posted February 21, 2016 Author Posted February 21, 2016 Left side drivers board finished. The original transistor were in good shape so I kept them. Redone all solder points and gave it a good clean. Next item on the list right side. 1
unclemack Posted February 21, 2016 Posted February 21, 2016 I have great admiration for people that can undertake such a mammoth restoration... Watching with interest and envy... M 3
Zaphod Beeblebrox Posted February 21, 2016 Posted February 21, 2016 Left side drivers board finished. IMG_1521.JPG I note that you have replaced the original fusible (white ceramic) resistors with what appears to be non-fusible types. Correct? Unless, of course, the new replacements ARE fusibles?
walker1000 Posted February 21, 2016 Posted February 21, 2016 What a great project, a lot of fun and hard work then the reward of sitting down and listening to what you have done. 1
vintagejapan Posted February 21, 2016 Author Posted February 21, 2016 I note that you have replaced the original fusible (white ceramic) resistors with what appears to be non-fusible types. Correct? Unless, of course, the new replacements ARE fusibles? Fusibles were used as non flammable or flame retardant. Today's metal film are all non flammable. This was a recomandation of a fellow from audiokarma.
Zaphod Beeblebrox Posted February 21, 2016 Posted February 21, 2016 Fusibles were used as non flammable or flame retardant. Today's metal film are all non flammable. This was a recomandation of a fellow from audiokarma. Today's metal film resistors are most certainly NOT fusible. BIG difference. If you examine the original Yamaha resistors, you will note that they have a current rating stamped on them. This is the fusing current. A standard metal film resistor could easily absorb ten times (or much more than) it's rated current before failing. I would also dispute the claim that modern metal film resistors are non-flammable. That aside, it is the current rating that is important. I believe you may be risking your valuable V-FETs by not using fusible resistors.. 1
vintagejapan Posted February 21, 2016 Author Posted February 21, 2016 (edited) Today's metal film resistors are most certainly NOT fusible. BIG difference. If you examine the original Yamaha resistors, you will note that they have a current rating stamped on them. This is the fusing current. A standard metal film resistor could easily absorb ten times (or much more than) it's rated current before failing. I would also dispute the claim that modern metal film resistors are non-flammable. That aside, it is the current rating that is important. I believe you may be risking your valuable V-FETs by not using fusible resistors.. The fusible resistors were rated at 150mA. I replaced them with the same value 1/2 watt metal film. From the description of the protection circuit that should be acceptable. Edited February 22, 2016 by vintagejapan
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 So the fun continues :-) Left hand side was pretty straight forward. Here it is with all the parts installed. All the solder joints reflowed. One cap missing, is on order and will be in as soon as it arrives
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 Replacing the big 4 filtering caps is the hardest part. Need to take out the V-fets and the heatsinks for easy access. Unscrew the V-fets. At this stage mark the pairs (2SK76-2SJ26)
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 While here will give them a soapy bath. Wipe the heat paste first, don't want any of that stuff going down the drain.
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 Take your time unsoldering the 4 big caps, the pcb can be damaged if you try to force them out.
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 The rectifiers will be upgraded to Fairchild 600v30A stealth diodes :-)
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 Bigs caps are out. The new Panasonic of the same specs are smaller so a slight modification is required, that way they will stay nice and tight in place.
vintagejapan Posted February 22, 2016 Author Posted February 22, 2016 Caps are installed and also the diodes. 1
Guest Posted February 22, 2016 Posted February 22, 2016 So.....you're pretty much replacing EVERYTHING? Wow
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