Tips for constructing a good PTP build

[EtherealWidow]

Using terminal strips that is. I know there are some serious evil geniuses as far as this part of amp building goes, but do any of you have some tips for a novice on ending up with a good finished product?

[Stevem]

First and foremost is to keep grid wires as short as you can as grid wires with a high impedance on them act like a antenna, and in stages where your signal level is low they will pick up all sorts of noise crap and also high level signals from other stages which can make for a oscillation issue !
Note that as a signal passes on down stream once it has left the plate of a tube and passes through the next coupling cap that plate wire has now become a grid wire, so if need belayout wise make the plate wire section longer to accomplish the build!
When you are laying things out do it such that the output wires from the PI ( if it's a push pull amp) should be no longer than 3.5 to 4 inches, once again to ward off a potencial oscillation issue .
Heater supply wires should be twisted a hight as possible ( by means of a drill even) and layed flat on the chassis and then the wires off of at least the preamp tube sockets should be raised up off the socket and sent on there way.
All grid wires in the preamp section should be shielded and grounded at only one end, and this grounding point for example should be where that gain stages cathode resistor gets its ground, and speaking of grounds you should use a star type grounding system.
The speaker output jacks and the OT should be as far away from the input jack(s) and first gain stage as is possible with the size chassis you are dealing with!
Hope these little tid bits help, and others will likely chime in with more for Ya!

[Cantplay]

Draw your layout and just stare at it.

Try to build on the socket and eliminate as much of the tag points and wire as you can. Try to orient your sockets so that wires are as short as they can be and cross less.

John

[Structo]

Take a look at other PTP builds here and try to copy good technique.

[Stevem]

Good point there cantplay!,you can mount a bunch of the tone stack components right on the pots to help make for very short grid wires, in fact this can cure oscillation problems!

[Leo_Gnardo]

Clean them tie strip lugs & component leads before soldering, should go without saying. A touch up with wire brush or fine sandpaper can work wonders. Sometimes a little extra help from Nokorode or similar flux. A good iron with a good tip, there's a good tip for ya. I use a 35W heater, medium chisel (screwdriver) tip & dial it down @ 10% with a Variac. Some have fancier heat-controlled irons, they're good too of course but if the tip is pitted, doesn't matter what, you'll have a miserable time soldering. Good luck! Some of the best were built on tie strip, Matchless f'rinstance.

[Phil_S]

Think of the schematic as your layout. Bend it into a horseshoe to compact it. PTP is rather circular in it's layout. I did one a while back. PT in the NE corner, OT in the SE corner. Input at the SW corner, power tubes South Center near the OT. Rectifier North Center near the PT. PI in the middle. Don't know if that makes sense, but that's it.

Also, hand as many component items as you can on the tube socket pins. Use terminal strips to support other end and and as a junction if they don't reach. No long flying leads.

As always, separate filament wires from the other stuff. Here's the build I'm talking about. http://home.comcast.net/~psymonds/GA20.htm

[EtherealWidow]

Definitely some good tips. Thanks y'all. Knew about keeping grid wires short, although didn't consider the transition to a grid wire through the coupling cap. Mounting most things to tube sockets also sounds great. Phil, unfortunately this chassis is nothing close to spacious. It's just a long rectangle, so the horseshoe plan is out. Also, I currently have the OT pretty far away from the PT, but very near the input jack and it's causing problems. I think I'm gonna take Xtian's advice from another thread and see if I can manipulate the flux lines of the PT from interfering with the OT using the choke I have.

[stephenl]

Take a look at the pics on Bruce Clements site - BC AUDIO. He takes PTP to an artform.

[Phil_S]

Phil, unfortunately this chassis is nothing close to spacious. It's just a long rectangle, so the horseshoe plan is out.

I should not have assumed. You know the old saying about that. Long rectangle is even better. Just line it up and build it. If not already drilled for sockets, think very carefully about socket placement.

[EtherealWidow]

Seen Bruce's stuff. Kind of ridiculous in a good way. Chassis is predrilled and everything. Just gotta install the strips and wire up components.

[schaublin65]

Hi,

another vote for BC Audio. Just wonderful.

take care...

[ampdoc1]

I'm in the middle of a PTP, and it is going to be pretty,...neat inside. So far so good!

But, if I had it do do again, I would have first made a neat drawing of the schematic, enlarged to fit the chassis size, then cut out each "section", and tape them to the chassis to fit. This is a pretty quick way to get an idea where to start.

Layout to minimize any noise is a hit and miss deal, but the above info is right on.

Luckily for me, I built this once before for a friend, and am now using it to guide me with the wiring.

[rp]

Phil, unfortunately this chassis is nothing close to spacious. It's just a long rectangle, so the horseshoe plan is out.

I should not have assumed. You know the old saying about that. Long rectangle is even better. Just line it up and build it. If not already drilled for sockets, think very carefully about socket placement.

Here's my build in a long rectangle, Matchless Lightning:

[Phil_S]

rp: that's a semi-cheat. You've used the terminal strips to emulate a turret board.

Don't get me wrong here. This isn't criticism in any way. It is a great looking build. I'm doubtful I could touch that in terms of ingenuity and tidiness. I like what you did. In a sense, it is a like having a totally transparent turret board. It's like using a board without the board. It opens of pathways for wiring. I have to try this, with tubes inside the terminal strips.

My statement is splitting hairs on when it stops being PTP. I'd call that a hybrid. It's way to tidy to look PTP.