JTM45/Bassman true point to point layout

[Silvio55]

Hi! I'm starting the build of a JTM45, this will be my third amp project, and I wanted to build it using point to point style, this means with no board with eyelets or turrets, just some terminal strips and soldering everything to the sockets and pots.
I have never made and amp this way, I'm trying to determinate what would be the better layout for this amp, I think it will be better having the trafos in each end of the chassis, the preamp tubes in the front and the power tubes at the back (like a Hiwatt), but I'm not sure.
Since it's my first build using point to point, I would like to see pictures or layout drawings of a JTM45 or a 5f6 Bassman made with this method, or if anybody can help me with the layout.
Thanks!

[guitarmike2107]

never seen one myself, have a look Badcat and Matchless builds for some ideas on how to approach it .. good luck

[Tom Phillips]

One of the advantages of true point to point wiring is that you have lots of freedom to mount parts in optimum locations and to minimize extra wire runs such as for a signal going over to a parts board to connect to a component and then back to the section of the circuit where it originated. However, (and this is a big however) you need a very good working knowledge of circuitry and the ability to plan out a good layout. When you are just building one amp from scratch you should be prepared to do some rework during and after the build. I personally like doing point-to-point wiring but is is more as an art form and for personal challenge and satisfaction. As to the tube placement, I would suggest that you position them where they need to be to support the signal flow. For example, the first pre-amp stage input tube could be near the input jack. There is no good electronic reason that tubes should be lined up evenly spaced along the back of the chassis. There are some PTP wiring layouts in the TUT series of books by Kevin O'Connor. You might also find some useful tips by searching out old audio amp kit build manuals or Sam's Photofact books covering early HiFi Pre-amps and power amps. I'll look for some examples that I can post but the only guitar amp material I have showing PTP layouts is in the copyrighted Kevin O'Connor books that I own.
Cheers,
Tom

[Justin Thomas]

Are you doing it in a gutted chassis of some sort, or are you using a dedicated JTM45/Bassman chassis? I often find it easier to follow the existing layout in a gutted chassis... another option is to use two parallel sets of terminal strips where the edges of the circuit board would usually be... I've done 2 PTP builds; would pics help? One was a Spitfire in a Stromberg PA, the other was an Orangey-thing in a Gibson Thor...

Justin

[Silvio55]

Thanks guys! I'm making my own chassis, of aluminum, so I have the freedom of choosing whatever layout I want, but I think I will make it with the traditional layout and using eyelet board, I'm afraid of ending up with an amp with oscillations, ghosting and other issues that are hard to troubleshoot for me, I'm not a very experienced builder, it's just my third tube amp project, and my knowledge of electronics in general is amateurish at best.
Justin, I would like to see your pictures anyway, if it's possible.

[Justin Thomas]

Might take a bit, as I'll have to zip all my pics. All of them exceed the attachment size... Sorry, but I'll find a way.

Justin