Pre-wiring a PR board

[p2pAmps]

Guys, I thought I would share a few thought on building a Hoffman Princeton Reverb.  Having built a number of these I have settled in on the way I personally wire these boards.  That is, I wire them prior to adding any components.  It just seems to me the best order of operation is to pre-wire.  I have also started drilling the board and running each wire through the board which helps it look neater and also allows the wire to lay down on the chassis better.  I am using Teflon wire on my PR builds. 

Anyway here are a few pics of one I am building now...

If any one has any improvements I would welcome your thoughts.  My goal is to build the best and cleanest Fender Clone possible...

[Fresh_Start]

You work is so clean it's almost impossible to add anything. You are asking for thoughts, so here goes.

Having all of the wires go down on the chassis ASAP adds to that super clean look.  I need all 3 dimensions to separate wires and get an amp as quiet as possible, so I only lay plate wires down on the chassis.  I definitely keep grid wires up away from plates.  But I know your builds are as quiet as they are clean so that's just a thought for other builders.

You use Sluckey's up through the turret approach for under board jumpers. I prefer to have a hole next to the turret and have the jumper actually soldered around the turret topside. Just a preference.

I assume that you put a ground bus on the pots. I prefer to have a board mounted ground bus.  It lets me complete more connections before putting the board in the chassis, and anyone can replace a pot later if ever needed. Also works well with filter caps along the front edge of the board. But again, that's just a matter of preference.

Most respectfully,
Chip

[p2pAmps]

You use Sluckey's up through the turret approach for under board jumpers. I prefer to have a hole next to the turret and have the jumper actually soldered around the turret topside. Just a preference.

Hey Chip,

Thanks for your comments.  So one clarification for you.  I am drilling a hole next to the turret and wrapping each wire around the turret topside and soldering.  You have to look close the the pics.  I make the 1/2 loop in the wire and a 90 degree bend, then run it through the hole from the top and wrap the wire before soldering.  If I solder the wire prior to running through the hole it can tear or damage the teflon.  I found the other way easier, faster, and cleaner for me.

As far as the ground buss to the board goes, I hear what you are saying...  Truth is I could probably get away with just the brass plate as Fender did but the buss is added insurance.  I will chew on that for a minute.

Scaggs

[p2pAmps]

BTW, Here are the build pics as I go.

http://p2pamps.com/rmpr

[sluckey]

That's basically the same method I use. I have an extra step in my build process that I don't think I've ever mentioned. I also use stranded Teflon wire which can be difficult to strip and tin with the board installed in the chassis. So, after my board is loaded and wired with extra long wires, I temporarily install the board and trim all the wires to final length. Then I remove the board for easy access to strip and tin the wires. Finally, the board is installed in the chassis ready to be soldered to sockets, pots, etc.

This process takes a lot of extra time but my hourly rates are very affordable. I like using Teflon wire and I think the results are worth it.

[p2pAmps]

That's basically the same method I use. I have an extra step in my build process that I don't think I've ever mentioned. I also use stranded Teflon wire which can be difficult to strip and tin with the board installed in the chassis. So, after my board is loaded and wired with extra long wires, I temporarily install the board and trim all the wires to final length. Then I remove the board for easy access to strip and tin the wires. Finally, the board is installed in the chassis ready to be soldered to sockets, pots, etc.

This process takes a lot of extra time but my hourly rates are very affordable. I like using Teflon wire and I think the results are worth it.

That's a good idea Steve.  I use a totally different stripper for telfon too and in small areas it's impossible to use to so I resort to a razor blade.  Thanks for the tip...

[mresistor]

Nice work.    You're buying the boards pre-drilled from Doug right? My changes would involve turret spacing on the board to accommodate larger capacitors, I actually like the mallory OD 715's a lot in this amp and there is little room to mount them - one has to fold the leads underneath the cap and I would rather go straight down to the turret. To do this involves laying out your own board and drilling it. There is quite a bit of real estate left on the board on both sides to make component spacing a little wider IMO.


Have you considered the MC 40-18087 OT? I have one on a Single Channel DR I built and this OT is absolutely fantastic sounding. Lots of grunt and chime and everything else. Especially nice if you are running JJ 6V6.



 

[mresistor]

Oh I forgot -  Where are you sourcing the clear insulating tubing for your components? I like the looks of it.


Chip was talking about UNDER the board jumpers and using Sluckeys method of coming up from underneath through the center of the turret. Looks like you are using that method for the jumpers.

[p2pAmps]

Oh I forgot -  Where are you sourcing the clear insulating tubing for your components? I like the looks of it.

eBay is where I find it.  Search for teflon spaghetti tubing...

[jojokeo]

Hi Mike,

The spaghetti tubing looks very nice as does everything else. But...why use it in the first place? You know there's no chance of anything moving around and touching each other once soldered so it's simply cosmetic. I suppose your prospective clients see that and combined with everything else looking so pretty it's what helps them decide to pull the trigger. I also agree with Chip's comments regarding the 3 planes or dimensions but practicality and beauty are usually mutually exclusive. Lastly, I've read where Teflon fumes are very toxic. Have you heard or read anything about this? I'm curious if it's that serious or not, just like breathing solder fumes or eating & smoking after handling leaded solder??? Sorry, not trying to hijack your thread however it's relevant here but maybe a topic for another thread? Thumbs up as always!

[p2pAmps]

Hi Mike,

The spaghetti tubing looks very nice as does everything else. But...why use it in the first place? You know there's no chance of anything moving around and touching each other once soldered so it's simply cosmetic. I suppose your prospective clients see that and combined with everything else looking so pretty it's what helps them decide to pull the trigger. I also agree with Chip's comments regarding the 3 planes or dimensions but practicality and beauty are usually mutually exclusive. Lastly, I've read where Teflon fumes are very toxic. Have you heard or read anything about this? I'm curious if it's that serious or not, just like breathing solder fumes or eating & smoking after handling leaded solder??? Sorry, not trying to hijack your thread however it's relevant here but maybe a topic for another thread? Thumbs up as always!

Hey Buddy,

ok, so I use the spaghetti tubing cause I get an extra 100 bucks for the work.  Totally up to the customer who has the choice.  I explain that it is mostly a cosmetic thing and the circuit board is just as good without it.  9 out of 10 want it so I oblige. 

As far as the teflon fumes go, I have made a big attempt to burn this stuff on purpose and with my iron at 700-750 I have not been able to make smoke yet.  I did install a bathroom exhaust fan above my bench for solder fumes and it works quite well.  I do not smoke but I do eat LOL...

Always good to hear from ya jojo

[HotBluePlates]

... I have an extra step in my build process that I don't think I've ever mentioned. ... after my board is loaded and wired with extra long wires, I temporarily install the board and trim all the wires to final length. ...

Sluckey probably isn't building many of the same item, but it seems you have repeat business for certain models.

Would it be worth it to you to figure out the "typical length" of some of the board wiring so you can precut them and minimize waste? I know Fender had pre-cut lengths of the push-back wire at assembly stations, and perhaps Kendrick did it too for their builds. Fortunately, they didn't have to deal with stripping those wires when installing in the amp.

I toyed with the idea of precut lengths to avoid having to trim-to-length/strip once the board was in the chassis, but I never did many of the same model repeatedly and so never got to that stage.

[Shack]

Great thread for me at the right time, cause as soon as my OT comes in, thats where ill be on my PR build....I only hope to make mine half as neat as those boards or Dougs and ill be happy :)

I it seems I ordered 2 reverb transformers by accident, so maybe ill build a reverb or revibe unit next :P

[Paul1453]

How much for a prewired board including shipping?