Firstwatt F4 PCBs still available?

jrebman · « **on:** 20 Jul 2009, 10:59 pm »

Does anybody know if there are any sources for new F4 PC boards -- both amp and PSU around?

I've been out of the loop for a while and would like to get some boards to make a stock, stereo F4 with dual mono supplies.

Any help appreciated.

Thanks,

Jim

Lyndon · « **Reply #1 on:** 20 Jul 2009, 11:03 pm »

Jim,
You could also post your question in the Nelson Pass Forum over at diyaudio.com. I would also ping
Peter Daniels of Canada, but I think he made the boards for the F3, but it may be the F4.
Good luck!
Lyndon

dweekie · « **Reply #2 on:** 24 Jul 2009, 06:53 am »

jrebman · « **Reply #3 on:** 24 Jul 2009, 09:10 am »

Not sure what that is, but I can't see it.

Peter Daniel has no F4 boards left and doesn't think he'll be making any more. He does have F2 though.

-- Jim

JoshK · « **Reply #4 on:** 24 Jul 2009, 01:18 pm »

Jim,

I'll check what boards I have from Peter. I always forget which ones they are. ~~I bought 4 boards, I want to say they are the F4 boards, but don't hold me to that. I don't have the PSU boards as he didn't have any left over.~~

I want to build the F3. I'm also curious about mating the Aikido with the F4 too, but more interested in hearing the F3. How many are you looking for, just 2?

OK, I found one of my email receipts from Peter and it says that I ordered 2 F4 boards and 2 PSU boards. I know I have some other boards from him as well, can't remember which amp those were for.

I could possibly let go of the F4 boards if you are having a hard time as it won't be anytime soon that I get to building them. If you have F3 boards you'd like to trade, that would be even better.

sts9fan · « **Reply #5 on:** 24 Jul 2009, 01:22 pm »

I will sell you one

strider · « **Reply #6 on:** 24 Jul 2009, 02:38 pm »

I bought PSU pcbs from poster cviller on diyaudio a couple months ago. Haven't used them yet, but they look to be of very nice quality.

Believe I found info on them buried in his F5 GB thread here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=134554

Very quick shipping.

Ben

jrebman · « **Reply #7 on:** 24 Jul 2009, 05:20 pm »

Josh,

I'm following up with one of the folks here who sent me an email first, but thanks. Maybe that was you STS9fan?

Ben, thanks I'll look into that PSU board if the other guy doesn't have any.

Josh, I don't think I ever recall seeing F3 boards, but I could be wrong, but in either case, I don't have any.

I'll have to ask Jon VerHalen which he thinks works best with the Alerions and Lowther drivers but the F4 seems like the best choice to me as it will be used to boost the output of a low power SET.

-- Jim

JoshK · « **Reply #8 on:** 24 Jul 2009, 06:07 pm »

The F4 is the one for boosting SET amps and such.

sts9fan · « **Reply #9 on:** 24 Jul 2009, 09:06 pm »

What type of preamplifier are you using? If it's not highish gain go with a F3 or F5. The F4 needs either a set or 18-20db preamp.

jrebman · « **Reply #10 on:** 24 Jul 2009, 10:47 pm »

I most likely won't be using a preamp, at least at this point. I'll use either my Carina and a SET of some sort or another -- either a John Tucker design parafeed 45 or something with a 10y output tube -- either of which only make about 1.5 watts. That's why I wanted the F4, but the F2 is also a transconductance amp and may also work in this arrangement, but has less power and I don't know if the circuit is optimum for use with a SET in front of it.

-- Jim

sts9fan · « **Reply #11 on:** 24 Jul 2009, 11:03 pm »

F4 and F2 are not that similar. F1 and F2 are the current amps. G4 is the power buffer.

jrebman · « **Reply #12 on:** 24 Jul 2009, 11:23 pm »

Which is why I'm looking for F4 boards. I only mentioned the F2 because I know Jon at Lowther America has had very good results with this amp and the Lowther drivers. The others may be nice too, but I haven't talked to him about them.

-- Jim

sts9fan · « **Reply #13 on:** 25 Jul 2009, 12:30 am »

I used an F1 with my Druids and it was fantastic.

jrebman · « **Reply #14 on:** 25 Jul 2009, 10:58 pm »

Dan B.,

I replied to your email -- don't know if you got that or not, but if not, try sending me a PM.

Thanks,

Jim

jrebman · « **Reply #15 on:** 30 Jul 2009, 06:01 pm »

Well, I now have a couple of F4 boards on the way. Now I just have to hunt down a couple PSU boards, the BOM, etc., and if anybody has a good source for sets of matched output devices, that would be appreciated as well.

-- Jim

dweekie · « **Reply #16 on:** 30 Jul 2009, 08:29 pm »

http://www.tech-diy.com/Store/CloneKits.htm

He is member JackInNJ on diyaudio. Nelson Pass gave his permission for him to sell parts (not boards) for the F series amps. You can order the whole kit or just the matched components as well (no psu kits though). It's a good BOM to start off with.

I would send cviller on diyaudio a message to see if he has any PSU boards since they are identical with the F5 (http://www.diyaudio.com/forums/member.php?s=f5a1e992ee5538cbe79c7d13f80815ec&action=getinfo&userid=58841). I purchased my F5 set from him in the last group buy. You could also easily do without the PSU boards. They are already extremely simple, consisting of only a C-C-(4R)-C-C arrangement with one additional resistor onboard since the rectifier and other components are offboard. You could even do just CRC with bigger caps, which Peter Daniel prefers over multiple caps. If you decide to use premium caps (Jensen, Sikorel, BHC Split foil, etc), they most likely wouldn't fit the boards anyway.

Hope that helps.

jrebman · « **Reply #17 on:** 31 Jul 2009, 12:11 am »

Dweekie,

Thanks -- now I remember jackinnj -- I'll drop him a line. Was thinking probably mundorf, nichicon KG super-through, and maybe a final jensen, but I really don't know yet, so maybe it is best I just build up my PSUs point to point.
Thanks,

Jim

TomS · « **Reply #18 on:** 31 Jul 2009, 01:51 am »

Jim,

I'd just use the Panasonic TSHA caps Nelson uses. A number of people tried the 4-pole Jensens among others and didn't see a major gain for the money. The Panasonics sound great in my F4 Mono's and F5 using both Peter's power supply and CViller's version as well. Your money is better spent with dual mono supplies - 2 transformers and power supply boards than on fancier caps. I tried many combinations and this one works. Mills power resistors or the blue Panasonic 0.47 ohm resistors are fine. That's what he uses too. Note, you'll need the tiny RN50 metal film resistors in Peter's boards.

Tom

jrebman · « **Reply #19 on:** 31 Jul 2009, 01:56 am »

Tom,

Thanks, and yes, I should have mentioned those as well. A lot of very respectable designers use them and find them excellent -- the panasonics, that is. Dual monos for sure, probably even separate chassis so the amp can be placed close to the speaker.

Glad to hear you're liking yours.

-- Jim