no thanks mate, i just made a few materials orders that wiped me out a bit and i'm concentrating on getting my 2 ways boxed up and saving a bit of coin for any extras i might need for the wire amps, so will be a few weeks yet. thanks for thinking of me though
I was planning adding clouds and airplanes on the top cover
I really can't wait to finish this project.
I will have all transfos and power supplies in a separate chassis to keep the AC away.
Do
Unfortunately not. It is still a really good JC-80 clone and the sound is quite AMAZING!
You should build one as well!
Do
Wolfsin - Which Caddocks are 4 ohms? The only one i can think might be in the Borbely regulator as the series R in the shunt, but nothing in the JC 80 or Blowtorch is that low - for that matter what is 33 ohms used in?
Pinnocchio - very nice boards and asssembly. My JC 80 (now Blowtorch ?) boards are blue and therefore must sound very different ( kind of blue actually) or I would have no credibility on this site.
Pinnocchio - very nice boards and asssembly. My JC 80 (now Blowtorch ?) boards are blue and therefore must sound very different ( kind of blue actually) or I would have no credibility on this site.
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Thanks!
You're absolutely true, color dictates the sound signature!
Actually, red is from the good seller and blue from the crappy one...
Just kidding! I saw them both and they're identical aside color.Ciao!
Do
I originally purchased 22r caddocks (BOM calls for 27r) but unsure of authenticity. They share Do's gonzo heatsinks with the output transistors. The 33r are authentic. The four was a quantity not a resistance.
My question was how much effect using something other than 27r would have on the circuit. At the time I started this the cost of caddocks seemed relatively high but in light of the full cost not so much. By paralleling 33r with 150r my per channel cost is just $12, I hit the BOM squarely, and cooling is not an issue. Know anybody who needs 22r caddocks?
Why in the world do you want sloppy 10% tolerance resistors in your equipment?
They're the same resistors as their 1% counterparts. Just might be 10% +/- of their target value. He measured them very close to 27R. If they're all matched closely to the value he wants (which is 27R) then they won't be budging afterwards.
Should be all good.
Of course, he took a chance since you're never 100% sure with 10% (they could have ended up 34R instead) but it seem to have paid off.
Lucky him!
Ciao!
Do
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C is better than BASIC precisely because it is terse
Well, actually, not really luck. 5% of 33 is 1.65r so 34r resistors get sold as 5%. Since the next higher value is 36r, the 5% range on those extends down below 35r. My point was that if you can accept something other than an exact standard value, choosing 10% may not be a 'sloppy' choice at all but rather one that yields tight clusters of values that can be easily matched almost exactly. At $1.49 rather than $10 for parts that are every bit as good as (in this case better than 1%) seems to me a tip worth passing on.
Clearly this is a tip that does not work for higher resistance values where the range between standard values is greater. Take 150r and 200r for example. The 10% range stops at 165r and then starts again at 180r. Tolerances are of extreme value for machine insertable parts but IMO nearly meaningless for the diyer who carefully hand matches.
Thanks, Do, for 'splaining most of my thinking. It was nice to have an opportunity to fully explain what had evidently not been adequately covered. When I think of what John must go through to communicate to the rest of us it nearly brings me to tears.
Well, actually, not really luck. 5% of 33 is 1.65r so 34r resistors get sold as 5%. Since the next higher value is 36r, the 5% range on those extends down below 35r. My point was that if you can accept something other than an exact standard value, choosing 10% may not be a 'sloppy' choice at all but rather one that yields tight clusters of values that can be easily matched almost exactly. At $1.49 rather than $10 for parts that are every bit as good as (in this case better than 1%) seems to me a tip worth passing on.
Clearly this is a tip that does not work for higher resistance values where the range between standard values is greater. Take 150r and 200r for example. The 10% range stops at 165r and then starts again at 180r. Tolerances are of extreme value for machine insertable parts but IMO nearly meaningless for the diyer who carefully hand matches.
Thanks, Do, for 'splaining most of my thinking. It was nice to have an opportunity to fully explain what had evidently not been adequately covered.
When I think of what John must go through to communicate to the rest of us it nearly brings me to tears.
Contact Stanton on Jim's Audio (ebay). I'm pretty sure he still have some available. They're not cheap!
Ciao!
Do
Duals v. singles
Toshiba duals have been picked over, perhaps repeatedly, in search of matches between the two transistors. If one is able to purchase an original (the risk of that being not the case is growing) the chance of a good match between the two transistors is slight else it would have been selected previously.
An alternative that results in poorer bonding (but likely better matching) is to search for matched singles (note a pair of j74 == one j109). Whenever two pools are pooled (not possible with duals) additional good matches may be found.
My strategy was to find very good matches of the rarer P channel parts, as close as possible to the top of the BL range, and then come as close as possible with a pair of well matched N channel parts, or possibly a dual complementary device. That done, look around among diyAudio threads for thermal bonding solutions or consider the one I suggested.
This is not to suggest that any vendor might behave unscrupously or, unknowingly sell fakes, but merely to recognize the shortages that are known to exist.
Toshiba duals have been picked over, perhaps repeatedly, in search of matches between the two transistors. If one is able to purchase an original (the risk of that being not the case is growing) the chance of a good match between the two transistors is slight else it would have been selected previously.
An alternative that results in poorer bonding (but likely better matching) is to search for matched singles (note a pair of j74 == one j109). Whenever two pools are pooled (not possible with duals) additional good matches may be found.
My strategy was to find very good matches of the rarer P channel parts, as close as possible to the top of the BL range, and then come as close as possible with a pair of well matched N channel parts, or possibly a dual complementary device. That done, look around among diyAudio threads for thermal bonding solutions or consider the one I suggested.
This is not to suggest that any vendor might behave unscrupously or, unknowingly sell fakes, but merely to recognize the shortages that are known to exist.
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