The diyAudio Firstwatt F6

[6L6]

That will be a great combo!

 

[zman01]

longspeak.

The F6 is a very nice amplifier, and wishing you fun with the build project.

Have you got your other items sorted out like PCB components, chassis, power transformer, power supply etc?

 

[longspeak]

Have you got your other items sorted out like PCB components, chassis, power transformer, power supply etc?

Thank you for the encouragement!


I ordered the PCB and parts kit, I have some K170 and J74 coming from punkydawgs. I haven't sorted the chassis and PSU yet, I'm thinking a xfmr from Antek and the 4U chassis from modushop?

 

[zman01]

longspeak,

Looks like you are progressing nicely!

For chassis, I personally prefer a little bit more depth than 300 mm - makes working inside the chassis and placing stuff easier. The Modushop chassis is available in 400 mm depth also; the larger heat-sinks will keep things slightly cooler too. 4U height is good.

 

[ItsAllInMyHead]

Thank you for the encouragement!


I ordered the PCB and parts kit, I have some K170 and J74 coming from punkydawgs. I haven't sorted the chassis and PSU yet, I'm thinking a xfmr from Antek and the 4U chassis from modushop?

If you're not in "must have it now" mode - this this is an absolutely exceptional value, IMO. Some slight mods have been done by the OP to the UMS to allow better arrangement of the F6 on the heatsinks. If you have the room for the extra depth, go for it. Any chassis you listed will work and work well, but this one allows a bit more room to grow also, if that's a consideration.

Pico's Toxic Masculinity Class A Amp Chassis

Ultimate 4U 500mm Chassis - Who is interested?

 

[TungstenAudio]

Thumbs up for that 4U, 500mm chassis. I'm on the list to get two. Thinking one of the them could be a second F6 with newer Pico recommended Mosfets, and my diamond buffer front end. Crank the bias to 2.4 Amps no problem

 

[6L6]

That is an enormous case for an F6 even with big output devices!!

Overkill is fun... remember Nelson said, “There’s no such thing as heatsinks too big.” !!

 

[longspeak]

Pico's TM chassis looks interesting - how much larger is it compared to the factory F6 dimensions?

I also noticed that Jim's Audio has a power supply PCB that looks like a clone of the one in the F6, any thoughts? Here is the link:

CRC Power supply PCB for class A Power amplifiers ! - JIMS Audio

I think I want to go with the chassis mounted bridge rectifiers.

 

[Zen Mod]

Pico's Semi-Berserked chassis is too big for common F6

you'll hardly go with more than 40W per device, and with 80W of heat, that thingie will be just warm

 

[6L6]

For many years, Jim’s audio has made PCB for Pass designs (and others) with zero permission.

 

[Russellc]

True that, my F6 in 4U chassis didnt get overly warm at all, probably the least hot of my clones. Somewhat less than M2, definitely cooler than Aleph J or F5.

Russellc

 

[longspeak]

For many years, Jim’s audio has made PCB for Pass designs (and others) with zero permission.

That is the feedback I was looking for, as much as a I want to buy it I'll pass.


I don't need much power so I'll keep Pico's TM chassis in mind for the future but stick with a smaller pair of chassis for now.

 

[2 picoDumbs]

If you're the type of person would reuse the chassis then just get the big 4u x 500mm.
If you tend to buy a new chassis for every project then just get what doed the job.

 

[longspeak]

I'm the type that leaves something powered up in a cardboard box on the livingroom floor with a note that says "don't touch" - the cat can't read

Pico, many posts back you mentioned possibly trying some Exicon laterals, did you ever try them?

csample says he is going to make a bi-polar psu board similar to his F1/F1J design (F1 or F1J Amp and Power Supply Boards with UMS Mounting Pattern Group Buy) so I'm going to wait and get a couple of them.

 

[2 picoDumbs]

No never tried, but you want to get the double die laterals then reduce the closed loop gain to about 12dB.

That would be worthwhile trying.

 

[Nelson Pass]

For many years, Jim’s audio has made PCB for Pass designs (and others) with zero permission.

You cannot accuse him of having bad taste.

 

[6L6]

 

[Chiptech]

Hi Everyone,

I am looking forward to building the F6. I have an extra set of boards. I think two sets which should be enough insurance for me.

If you are looking for a F6 Set of boards, message me and I will mail them to you.

 

[Chiptech]

I have found someone for the boards.

thanks

 

[audiosteve]

So going back a few posts to the heat sink message where it was said that the 4U unit did not run hot..I'm looking for some feedback. I want to make mine 2U high and have found some heatsinks that extend out twice as far as the DIYAudio heatsinks. Temp coefficient for the sink is .35C/W I was thinking this should work OK. Does anyone have any comments on that? Thanks in advnce for any feedback.