New B2 for complete rebuild.

Settled on Vampire BP-HEX (about $15 each with current sale) for the binding posts and CMC for the RCA jacks ($6.50 each).
 
belgianbrain,
How's the project coming along? By the way I use the Schiit Bifrost Multibit and Schiit Freya. Currently using them with a repaired and recapped P2200 I picked up off Ebay a month or so ago. Sounds really great to me.
 
The project goes slowly. I've been working on the rear panel lately, which is very time consuming. I think I'm done now. New IEC power connector, new binding posts, and new RCA jacks for the input. Used a solid brass plate to mount the brass binding posts.

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Thought I would make major progress on this over the holidays. :rflmao:

Finally got back to it this weekend and did the two power transistor boards and sinks. Cleaned everything. Replaced the 0.22 Ohm resistors in the signal path with Mundorf MResist Supreme. Changed the 50nF green cap with Panasonic polyproylene.

In this B2, I have the unpainted heat sinks that use mica insulators, so I replaced the insulators and heat sink grease with Aavid Thermalloy Thermasil insulators (Mfg. P/N 53-03-2G).

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I fired the power supply board up yesterday to adjust the +/- 85v supply. The driver boards and power VFET boards are currently disconnected.

CLICK. BOOYEAH.
 
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Well, spring/summer sure took the wind out of my sails! But, free time is mine again as the weather gets cold.

Driver boards are done. Meter board is done.

I only have the last 10% to go so it should be complete in a couple of weeks. I'll post some finishing photos and thoughts soon.
 
Alright. I ran into a snag trying to adjust the driver boards. Basically, I replaced all resistors in the signal path, many fusible resistors, and all capacitors I had polyproylene replacements for. I also changed the big electrolytic with Nichicon Muse.

I have unit assembled with VFETs removed. Only one VFET board and driver board is installed with 10k resistor between PG and NF and 10K again between NG and NF to simulate presence of VFETs for rough adjustments.

DC balance can be set to zero with VR101, but bias remains at zero regardless of VR102.

Front power meter for the installed driver board stays elevated at about 0.01W (this one has me a bit perplexed as how does signal escape FET board with no FETs installed?).

I took some readings and I get the following:

+B2=85V
-B2=-85V
+B=60V
-B=-60V
PG=15V (a tiny bit high, should be 13.5)
NG=-1.3V (very low, should be -13.5)
NS=0
NF=0
PS=0

Now both driver boards seem to do the same thing, which really has me scratching my head. I've rebuilt these driver boards before in another unit without issue. I'm also careful to measure each component I remove and measure each replacement part just to make sure it's a match. Yet, if the issue is on the driver board, it seems I made exactly the same mistake on both driver boards. :dunno:

I'd appreciate any suggestions to help speed up this diagnosis.
 
Penance for carelessness. :). Thanks to Avionic for suggestions on repairing this. It is not pretty but it works.

Now that both driver boards are fixed I can finally finish this amp.

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Front power meter for the installed driver board stays elevated at about 0.01W (this one has me a bit perplexed as how does signal escape FET board with no FETs installed?).
Is the rear switch set to internal or external.
 
they did away with blue coating for all B-2s with serial number greater than 4249. That is what I understand. Any JDM B-2 with 5000+ serial number that I have seen, does not have the blue coating.

Yep , no blue coating in this B2. It had mica insulators on the VFETs. Replaced them with Aavid Thermalloy Thermasilinsulators. They work great if you don't over tighten, which took me awhile to learn. Good thing I bought extras.

B2 works now! Will post a few pictures after I adjust the bias with my THD analyzer.
 
Here is what the driver boards looked like when they were done. Literally every passive component was changed except for varistor diodes. Resistors are all metal film except for a few Takman Rex carbons in the signal path.

I focused only on things that affect sound or reliability in this B2. So, I only changed electrolytics on meter board and nothing else. Input switch board was not touched because it is bypassed with driver boards wired directly to new jacks on the rear. This board only functions now to switch between two speaker outputs.

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