Can anyone give me the dimensions of the latest F5T boards? I don't see the data in the store page anywhere. The store info shows that it is UMS compliant but that that doesn't help me with my own chassis -- I need the measurements please. A 2D CAD drawing like that provided for the Universal PSU board is what I'm looking for... Thanks.
Q1.1, Q2.2?
I've purchased two sets of the V3 boards from the store with the intent of making two 100w monoblocks. In reviewing the BOM for V3 I'm seeing 2 pair of input JFETS listed for Q1/2, Q1.1/2.2. It's my understanding that the .1 pads are optional for adding an additional pair of JFETs when cascoding but are not part of the original NP schematic. Please verify that this is the case. It's confusing for a noob like me when ordering parts off the BOM as I'm not sure whether I need 2 pair or 4.
I've purchased two sets of the V3 boards from the store with the intent of making two 100w monoblocks. In reviewing the BOM for V3 I'm seeing 2 pair of input JFETS listed for Q1/2, Q1.1/2.2. It's my understanding that the .1 pads are optional for adding an additional pair of JFETs when cascoding but are not part of the original NP schematic. Please verify that this is the case. It's confusing for a noob like me when ordering parts off the BOM as I'm not sure whether I need 2 pair or 4.
ottopilot, the front end is 60 x 90 mm with mounting holes in a 40 x 80 mm rectangle. Output boards 50 x 132 mm with mounting holes in a 40 x 120 rectangle, every 40 mm. Output device and diode mounts are in line with the board mounts, centered midway between the mounting holes, 20 mm and 100 mm from an edge. Refer to the UMS spec for how far from the mounting line to place the device mounting holes.
WaterDog, Reading the F5T article, it appears that NP suggests anything above 4 output device pairs you should consider adding the .1 input devices (which need to be matched to the appropriate Q1/Q2). You should be fine without them.
WaterDog, Reading the F5T article, it appears that NP suggests anything above 4 output device pairs you should consider adding the .1 input devices (which need to be matched to the appropriate Q1/Q2). You should be fine without them.
BobEllis, thanks...exactly what I needed. I have a set of the older beta boards but that gain board is more or less square with odd hole centers...60x64 or something like that. I couldn't find anything for the newer gain board. Thanks again.
Thanks, Bob. I have read it numerous times but I guess it didn't click. Appreciate the clarification.
The link to the product page in post 1 is broken. Can the OP or one of the moderators please fix it?
Here's the link.
F-5T (6 PCBs, Makes 2 channels; Rev3.0) - First Watt Clones - Power Amplifiers - Circuit Boards
Or just go to the DIY store link at the top of the page.
F-5T (6 PCBs, Makes 2 channels; Rev3.0) - First Watt Clones - Power Amplifiers - Circuit Boards
Or just go to the DIY store link at the top of the page.
I finally have gotten around to stuffing the boards, in an V2C configuration. Since this is really a V3 minus the two extra output boards that's the BOM I used and I found an error that I vaguely remember being discussed somewhere already. To help avoid mistakes and frustration the BOM should be updated.
The BOM reflects the schematic in the article, but there R26 is listed as 47K5, with the cascode voltage formula and R25 is shown as 10K. Both R25 and R26 should be calculated with the formula and 10K is the correct value for the nominally 1/3 rail voltage that NP calls for in the article. Using 47K5 you get 0.09 x rail voltage.
Can the BOM be updated to reflect R25 and R26 set the cascode voltage and the starting value is 10K?
The BOM reflects the schematic in the article, but there R26 is listed as 47K5, with the cascode voltage formula and R25 is shown as 10K. Both R25 and R26 should be calculated with the formula and 10K is the correct value for the nominally 1/3 rail voltage that NP calls for in the article. Using 47K5 you get 0.09 x rail voltage.
Can the BOM be updated to reflect R25 and R26 set the cascode voltage and the starting value is 10K?
It would be nice if much larger closeup pics of the store boards are posted at the store link. The small pics presently there are frankly quite useless and of no help especially to novices like me.
Thanks.
Thanks.
Could someone point me to what each test point on the store boards is for? I have the V2 boards I think.
F5 V3 board question
Could someone please tell me:
1) What is C1 on the output board? Is this C3 in the NP schematic. Also from the pics it looks like there is a C2 on the output board. What is that?
2) What is the hole size for the +/- /G/OP holes on the output and FE boards? They look pretty small in the pics.
Thanks.
Could someone please tell me:
1) What is C1 on the output board? Is this C3 in the NP schematic. Also from the pics it looks like there is a C2 on the output board. What is that?
2) What is the hole size for the +/- /G/OP holes on the output and FE boards? They look pretty small in the pics.
Thanks.
What are the dimensions of the boards?
What's the minimum height required to mount the boards on the heatsink (include power FETs and diodes)? Will they fit on a 90mm heatsink?
(I'm not asking if such a heatink provides enough heat dissipation)
What's the minimum height required to mount the boards on the heatsink (include power FETs and diodes)? Will they fit on a 90mm heatsink?
(I'm not asking if such a heatink provides enough heat dissipation)
The holes are ridiculously small. 14 awg will not fit.I drilled them out and used through hole PCB to wire solder cups to re-establish mechanical strength.
I am confused about the PSU requirements described on the DIY-Audio store:
A stereo F-5T v2 requires a bipolar power supply of (+/- 32V). This will require an 24V+24V (or 48V Center Tapped) transformer from 600-800VA...
The F-5T v3 will require two of the above PSU. (One for each monoblock)
As far as I understood Nelson Pass' original article describing the F5-TURBO V1, V2 and V3, the improvement of the V3 over the V2 is the addition of the cascode, which allows using higher PSU voltages with V3 than with V2. So why do they recommend using the same PSU (and hence the same voltage) for V2 and V3?
A stereo F-5T v2 requires a bipolar power supply of (+/- 32V). This will require an 24V+24V (or 48V Center Tapped) transformer from 600-800VA...
The F-5T v3 will require two of the above PSU. (One for each monoblock)
As far as I understood Nelson Pass' original article describing the F5-TURBO V1, V2 and V3, the improvement of the V3 over the V2 is the addition of the cascode, which allows using higher PSU voltages with V3 than with V2. So why do they recommend using the same PSU (and hence the same voltage) for V2 and V3?
That was merely stated that way to illustrate that the v3 would most normally be built as monoblocks using the 5U chassis. So 2 PSU would be needed.
A few lines later it says that the amp can be built with higher voltages.
A few lines later it says that the amp can be built with higher voltages.