Has anyone any idea as to using a F5 T v1 in a mono block configuration using two Mini Disspante 3U cases from the store.
My questions are. Will these cases be large enough, Will the heatsinks cope
Thanks
My questions are. Will these cases be large enough, Will the heatsinks cope
Thanks
I'm building standard v3 monoblock with 24V secondaries. Output power in this scenario should give me more than I need. I've got this caps so I could put them if it will improve anything.
What about R11/R12 for P2/N2? Do I also need them ? I mark them on screen.
In BOM for v3 there is R11/R12 only for P1, N1. Reference below.
I assume that this is current schematic:
So BOM and schematic looks same if i can read it correctly.
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Yes, install them. They make the temperature compensation thermistors work. (Which you also need.)
you only need them for one N and one P board pr ch. do NOT solder in thermistors on two P and two N boards pr ch.
Thanks for clarifications. What do you think about additional caps on P2 and N2 ?
You could, if you want. I don’t think it matters. I left mine empty.
Did you make R25 and R26 (front-end PCB) the same value? There’s an error on the schematic and I can’t read the stripes in your photos.
Did you make R25 and R26 (front-end PCB) the same value? There’s an error on the schematic and I can’t read the stripes in your photos.
Jim, Do you mean to install 2 sets of thermistors and R11/12 ? I don’t think that will work properly, especially given that the resistor values would need to be reworked due to having 2 thermistor circuits in parallel across the driver load resistor. You only need one thermistor given that you have only one driver circuit it is acting upon to rein in the bias current as temperature rises. Since the output mosfets are matched and share the same heatsink, a second one is redundant. If each board was mounted on a separate heatsink and you had 2 driver circuits, one for each board, then you would need to have 2 thermistors.
I only have one on my V3s and they have been in service for 3 years now with no issues.
I read about this error couple of times, but I thought it's already fixed and BOM is correct. There was plenty of time for doing this 😉
I installed everything with values specyfied in BOM so - R25 is 10K and R26 is 47.5K. Which should I replace or which value is correct ?
Screen below.
I think it was about additional caps for each board. As far as I'm concerned he was talking about adding R11 and R12 with one termistor on P1 and N1.
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The BOM repeats the error. The proper value is 10K for both R25 and R26, which will set the cascode voltage evenly on both rails, at approximately 1/3 the rail voltage.
One thermistor per phase, I am not suggesting doubling them.
Little rail capacitors if you want, your choice.
One thermistor per phase, I am not suggesting doubling them.
Little rail capacitors if you want, your choice.
When I was building my V3 there was some discussion about what voltage to shoot for on the cascodes. I think it was around 13 to 16 volts as a sweet spot. So, if you are looking to hit that range, the resistor ratio depends on the supply voltage you are using.
Yes and here's the formula for calculating the cascode voltage:
Cv = rail voltage / (R25 + R27) * R27
So for 32v rails: 32 / (10k + 4.7k) * 4.7k = 10.23v
R26 & R28 should be the same as R25 & R27.
Cv = rail voltage / (R25 + R27) * R27
So for 32v rails: 32 / (10k + 4.7k) * 4.7k = 10.23v
R26 & R28 should be the same as R25 & R27.
So should I go with 30V secondaries instead of 24 to get around 40V so rail will be around 13.3 ?
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Thanks. That makes the circuit physically smaller, which I think is better.
Just started cooking the amp again after adding the missing diode snubbing. May not get very far today.
The wooden moving dolly came that is going to be the amp stand. Once is leaves the workbench, it is (hopefully) staying off -- and I will need to move it around. It is very heavy. I'm guessing around 90 pounds. Which makes it 2lbs per peak watt.
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I added the snubbing diodes, and the noise did not change. Virtually identical. The THD went down a little though, to -84 dB.
Next thing to try is twist the power wiring that runs from the cap bank on the front panel of the amp to terminal strips at the back of the amp on the noisier channel tighter. This could be it, as the power wiring runs under the transformer.
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Changed my mind.....
..... I have gotta hear this thing first!!!!
Next thing to try is twist the power wiring that runs from the cap bank on the front panel of the amp to terminal strips at the back of the amp on the noisier channel tighter. This could be it, as the power wiring runs under the transformer.
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Changed my mind.....
..... I have gotta hear this thing first!!!!
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