| MikeW |
| Are the 10 k R46 and R61 connected to the +/- inputs? |
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| jh6you |
Maybe . . . thinking about the bleeder too much . . . :scratch2: uhhhh . . . when the power is turned off . . . the amp should die instantly . . . ? ? ? :)
Regards
jH |
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| Nelson Pass |
| quote: | Originally posted by jh6you
Maybe . . . thinking about the bleeder too much . . . :scratch2: uhhhh . . . when the power is turned off . . . the amp should die instantly . . . ? ? ? :) |
Maybe you are thinking about bleeder too much: Easy cure
for that - stop thinking and start experimenting.
Amp should die instantly? Amp might deserve to. Gets stake
driven right through heart!
We are fearless amplifier builders. Unafraid to stop simulating
and start building. What's the worst that can happen? You die?
No, amp dies! Maybe speaker, too!
Lose a couple of $$$!
MuuuuHahahahahahaha........!!!!
:darkside: |
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| pinkmouse |
Simulation?
You draw something on the back of a beermat, then you build it and it goes bang. What's to simulate? :) |
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| jh6you |
damn . . . who is so noisy . . . ? ? ?
Wuuuuuheheheheheh . . . ! ! ! :cheerful:
I would not lose a couple of $$$, but a little of $!
And it would provide me a good start to talk my
respectful wife successfully into the efficient
single unit speaker. Then, I could build the First Watt
on a strrong mmoonster PSU.
:drink:
. . . nice weekend !
Regards
jH |
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| Magura |
| quote: | Originally posted by pinkmouse
Simulation?
You draw something on the back of a beermat, then you build it and it goes bang. What's to simulate? :) |
My kind of guy :)
Magura :) |
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| MikeW |
| Thanks, I'll cut the trace and put in a jumper.:smash: |
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| MikeW |
One more question. R46 goes to R54 and R61 goes to R69. Do they go to the outputs?
It's only my second pre-amp. Thanks. :confused: |
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| Nelson Pass |
No. The genral rule for clear schematics is that crossed wires
are not connected unless there is a dot where they cross. Even
better, crossed wires are never connected - any connection is
represented by a "T" where they meet. |
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| jh6you |
Buy Horowitz&Hill THE ART OF ELECTRONICS . . .
And read Appendix A, HOW TO DRAW SCHEMATIC DIAGRAMS, on page 1056.
No . . . ! ! ! Just go to a book shop, and read it, then return it into the shelf . . .
Or, stealing book for studying is no sin . . . ;)
:drunk: . . . :drink:
Regards
jH |
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| GRollins |
Nope. Nelson draws his schematics using the Foresthills dialect of the language. In the local argot, a line that crosses straight over another line is a no connection. A line that connects is a dead end, such as the connection of R47 to the +input. Of course, there are incongruities just as in any language, in that C9 and R52 (can't read the number clearly) get a straight line connection instead of an offset one. That's the way it goes. It's a small hurdle that he puts in to test your commitment to building the circuit.
In any event, only the middle MOSFET (IRF610--Q?--number completely illegible, less than optimal scan) is active signal-wise. The upper one (IRF9610--Q?) and the lower one (IRF610--Q?) are current sources, and undriven ones at that, i.e. they are not Aleph current sources or anything of that nature. Nelson is just letting the collector of Q11 and Q12 connect via R46. How much AC goes across there, I couldn't say as I haven't built the circuit, but it might qualify as a sort of backdoor feedback. Note that the connection isn't part of the signal path, per se, as the ZTX parts only serve to set the current and tighten up the two current sources. They are DC servos that correct for AC signals across R44 (Q11) and R55 (Q12). Any deviation from pure DC gets passed back to the Gate of the MOSFET as a corrective signal, thus setting things right again.
Grey |
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| Blues |
| quote: | Originally posted by Nelson Pass
Maybe you are thinking about bleeder too much: Easy cure
for that - stop thinking and start experimenting.
Amp should die instantly? Amp might deserve to. Gets stake
driven right through heart!
We are fearless amplifier builders. Unafraid to stop simulating
and start building. What's the worst that can happen? You die?
No, amp dies! Maybe speaker, too!
Lose a couple of $$$!
MuuuuHahahahahahaha........!!!!
:darkside: |
Moderators, please move this to the other thread...where amps need to be bled:) |
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| MikeW |
| Here is the schematic. |
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| jh6you |
Yes
The book says: "1. Wires connecting are indicated by a heavy black dot; wires crossing, but not connecting, have no dot . . . 2. Four wires must not connect at a point; i.e., wires must not cross and connect.
Ladies and gentle men . . . the one, the only . . . Starina . . .
wo! wo! wo! wo! wo! wo . . . ! ! !
Regards
:faint: |
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| MikeW |
| Any other mistakes? |
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| jh6you |
One misprint. The size of R27
Regards
jH |
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| MikeW |
I found that one 221K. I have one channel built. I still need to do some testing. Thanks for the help.
Do R44,59,55,70 have to be more than 1/2 watt? The prototype board has 2 watt, but it looks like they should only see .7 volts across them. |
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| GRollins |
1/2W will do just fine...or 1/4W if you want. You're correct, there's only a steady .65VDC across them.
Grey |
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| MikeW |
| Should the minus input and output be shorted for single ended operation? |
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| GRollins |
Only the unused (in this case negative) input is shorted. Let the unused output flop around by itself; won't hurt anything.
Grey |
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