ODS Eyelet Boards

[Stephen1966]

Thanks Martin

[Stephen1966]

Eyelet board layouts with "standard" mounting centers for CE Chassis.

Hi Martin, I'm looking at these boards now. I'm comparing the latest eyelet boards [DIY_Eyelet_Boards_100W_ODS_Radial.pdf] with the old FET board drawn in the 'Dumble Overdrive special Complete Layout 9_28_2010b' layout [https://ampgarage.com/forum/viewtopic.php?f=5&t=5719]. I noticed several changes, possibly because the layout must be, what, 10 years old now? And component choices have evolved in the meantime. Could I ask a couple of questions about the FET preamp board and circuit?

First, the board dimensions. I measure the FET preamp board at 2" x 1.5" from the pdf. Is that right?

Next, I noticed you had substituted the NTE 452 JFET for a 2N4416A and along with this, the value of the board resistor coming off the signal leg (I'm assuming its 0.5W) has gone from 8.2k to approx. 2k. And similarly, the cathode resistor (I'm assuming this one is rated at 1W) has risen from 8.2k to approx. 22k. Are these changes because of the change of JFET transistor. I read somewhere, though I can't recall where at this moment, that the board resistor could be anywhere between 2.2k - 2.7k. What are the parameters we are dealing with here?

[martin manning]

First, the board dimensions. I measure the FET preamp board at 2" x 1.5" from the pdf. Is that right?

When the chassis with matching board sets became available, that set the standard for the board dimensions. The FET boost was done on a PCB, smaller than the original D eyelet board version, so I had to rework the layout for eyelets. Overall dimensions and mounting centers are listed in the .pdf next to each board.

Next, I noticed you had substituted the NTE 452 JFET for a 2N4416A and along with this, the value of the board resistor coming off the signal leg (I'm assuming its 0.5W) has gone from 8.2k to approx. 2k.

NTE is a replacement part reseller. You can use NTE452 or 2N4416A, but the name-branded part number will be available from Mouser, etc. The 2k is the source resistor, and should be adjusted to bias each individual FET.

And similarly, the cathode resistor (I'm assuming this one is rated at 1W) has risen from 8.2k to approx. 22k. Are these changes because of the change of JFET transistor. I read somewhere, though I can't recall where at this moment, that the board resistor could be anywhere between 2.2k - 2.7k. What are the parameters we are dealing with here?

The 22k resistor is the lower leg of the voltage divider (150k and 22k) that creates Vdd (voltage at the top of the 10k drain resistor) from the V1 supply voltage, and is pretty much independent of the FET used. The voltage should be checked and the value adjusted for each amp so that Vdd is ~20V.

Instructions for setting the bias and Vdd are here: https://ampgarage.com/forum/viewtopic.php?f=5&t=18389

[martin manning]

Added the schematic and a layout for the popular FET Boost relay with level control replacing the FET input jack.

[martin manning]

Found an error on the radial cap version of the bias/HT rectifier board... reversed cap. Also, now showing FWB connections on that board for Marshall PT.

[Stephen1966]

Thanks for pointing that out.

[dragonbat13]

Ok maybe a dumb question BUT,

If I just sent the .far files from the first page to a PCB manufacturing company they would be able to just use what's in the file to print me up some boards?

If so, who does everyone recommend to make some nice durable boards in some fancy color?

Please don't flame me.

[erwin_ve]

Ok maybe a dumb question BUT,

If I just sent the .far files from the first page to a PCB manufacturing company they would be able to just use what's in the file to print me up some boards?

If so, who does everyone recommend to make some nice durable boards in some fancy color?

Please don't flame me.

You mean the .rar file?
The file inside the .rar is a Sprint layout file.
Generally speaking you want to give a pcb fabricator a zipped gerber file, which is industry standard.
Procedure would be :
Make/edit the Sprint layout file to your likings.
Double check for errors.
Export to gerber/drill files.
Zip the gerber/drill files and ask pcb fabricator a quote with desired thickness, color, etc.

Erwin

[dragonbat13]

Ok maybe a dumb question BUT,

If I just sent the .far files from the first page to a PCB manufacturing company they would be able to just use what's in the file to print me up some boards?

If so, who does everyone recommend to make some nice durable boards in some fancy color?

Please don't flame me.

You mean the .rar file?
The file inside the .rar is a Sprint layout file.
Generally speaking you want to give a pcb fabricator a zipped gerber file, which is industry standard.
Procedure would be :
Make/edit the Sprint layout file to your likings.
Double check for errors.
Export to gerber/drill files.
Zip the gerber/drill files and ask pcb fabricator a quote with desired thickness, color, etc.

Erwin

Thanks for the good explanation.

[ViperDoc]

Has anyone made these relay boards recently, have any in stock, and would like to trade money for a small batch? Let me know...

[dorrisant]

Which ones are you looking for? I have a bunch of universal boards on the way. I can submit any or all of these if needed.

[ViperDoc]

Which ones are you looking for? I have a bunch of universal boards on the way. I can submit any or all of these if needed.

ODS Relay Board
ODS FET Boost
ODS FET Preamp

[dorrisant]

I designed the FET Relay and the universal looks the same as the OD relay. Still have to finish the FET Boost board. I will get back here with them soon.

[martin manning]

Has anyone made these relay boards recently, have any in stock, and would like to trade money for a small batch? Let me know...

You're looking for just the relay boards? The universal type can be used for any of the functions, i.e. OD, PAB, FET boost, and I think that's what most people are doing these days. I have no idea why HAD would choose to make the OD PCB different from the PAB. Seems like wasted effort to me.

[ViperDoc]

Has anyone made these relay boards recently, have any in stock, and would like to trade money for a small batch? Let me know...

You're looking for just the relay boards? The universal type can be used for any of the functions, i.e. OD, PAB, FET boost, and I think that's what most people are doing these days. I have no idea why HAD would choose to make the OD PCB different from the PAB. Seems like wasted effort to me.

Agreed. I don't know where to find a one-sided relay board. I can only find the two-sided Hoffman boards.