Rawson Repair Reflections

[rhthatcher]

F2J mostly assembled. Neither long skinny nor Peter Daniels boards fit the original chassis. So I opted to build up PD boards for another Rawson chassis I have. So the original parts that remain are donut and output devices. Amp boards are Peter Daniel’s design. PSU board is by Chas Sample. I really like this board! AC cap and all thermistors are on the board, it’s a really nice design. He is doing a group buy on F1 including this board. If you need a stereo single rail supply I recommend this board! My F1 kit by Chas is stuck somewhere the USPS logjam... I did the rectifier / snubber boards.

I tested the amp on dummy speakers and it’s singing. Left to do: add LEDs and front panel, final cooking and set trim pots. Then test in my main horn rig. Then send to the owner.

Pix show original vs new board, new psu board, and assembly for initial test.

[6L6]

Randy, at this point they are no longer “repairs” but the full-rotisserie, frame-off restoration and hot rod upgrade. There’s nothing left of the original except some metal bits, end everything you touch looks incredible.

Hats off to your amazing work!!

[poseidonsvoice]

Agreed! What an excellent thread, thanks for starting it Randy! Shout out from a former resident of University Heights, North Olmsted, and Fairview Park!

Best,
Anand.

[rhthatcher]

Originally Posted by 6L6

Randy, at this point they are no longer “repairs” but the full-rotisserie, frame-off restoration and hot rod upgrade. There’s nothing left of the original except some metal bits, end everything you touch looks incredible.

Hats off to your amazing work!!

Thanks! The "frame off" on this one is because the 2 sets of boards I got my hands on didn't fit the old chassis. I thought I could squeeze the "long skinny" ones in, but I made a mistake on dimensions. So this project got swapped into an old chassis on my shelf. The original chassis may get some old Aleph Mini J boards put in. But I'm not in a rush because I have Aleph J monoblocs, too.

I shake my head every time I look at the pic of the original board next to the Peter Daniels board. Night and day different.

[Eric]

Nice work, Randy! Have to say that I've never seen these Rawson builds before, they look like house burners... You deserve an award from the local fire dept!

[rhthatcher]

Thank you to everyone for the kind words!!

This F2J is now done. Blue LEDs installed. Cooked & biased. Gain checks out. Distortion looked as expected. Sound is great on my bench speakers.

My SissySIT will take a break a few days while I run the F2J in my active horn rig. It will run 500Hz and up into JBL 375s and a Fostex superwteeters.

Now I can get back to my Singing Bush build. I also got really nice F1 boards today from the Chas group buy. The good news is that the F1 boards fit in the F2J chassis I swapped out. Plus I have a donut and a pile of matched mosfets on the shelf. So the F1 will be a low cost build when I use what’s on the shelf. Maybe I can get the caps and resistors I’ll need for less than the cost of one SIT. I’ll say it again - Great job on the F1 boards Chas!

[rhthatcher]

I was digging through some pix and found this classic! These come from Aleph J and Aleph J Mini's. Maybe an F5 in the mix, too.

[6L6]

This would be a very appropriate place to use a "vomit .gif" or something similar.

I won't, only because that photo will likely induce a similar reaction.




Thank you for turning these abominations into amazing amplifiers.

[Andersonix]

It's a cry for help.