Difference between a circuit board and a turret/eyelet board??

[The Dude]

I know this is obvious to most here, but for clarification:

A turret board has turrets standing up off the board.


An eyelet board has eyelets for connections (different from turrets).


A printed circuit board has neither- only through holes and built in traces so that wires are not required for most connections.


There is nothing wrong with any of these methods of building a circuit.

[g1]

And here is an example of point to point construction, which uses no turret or eyelet boards, but may use terminal strips. Some people erroneously mistake point to point for 'hand-wired' which is I think the case for the guy who was griping about the Fender in that other forum.
Hand wired is pretty self explanatory, and could include any kind of construction. JCM800 used printed circuit boards which were hand wired to the tube sockets.

[Chuck H]

Well it's clearly handwired on eyelets. There are component "chalk lines" on the board and there may even be copper traces on the bottom side of that board. More likely Fender just did tidy under board bridges with lead wire but I don't know. Either way the build looks cool and I think it presents nicely along side "boutique" offerings. Kudos to Fender and their Pro Shop.

[Mick Bailey]

RT1 is an NTC thermistor in series with the incoming mains. The resistance is high on startup and drops as it heats up to normal operating temperature. The device has a temperature/resistance curve that gives a soft-start when turned on from cold. Fender has used these for quite a few years. The associated cap on that board is probably for noise suppression - needed these days for regulatory compliance.

[mozz]

How does a pcb twist wires for the filaments? I guess you could if you used plated thru holes on a 2 sided board. I prefer turrets or eyelets but have built a few champs using pcb boards and no problems.

[JJP]

How does a pcb twist wires for the filaments? I guess you could if you used plated thru holes on a 2 sided board. I prefer turrets or eyelets but have built a few champs using pcb boards and no problems.

I think the person who posted images of the inside of the amp in question (there's a link above to his post on tdpri.com) has concluded beyond a doubt that it is not PCB but rather, as Mick Bailey mention above, that it is "FR4 or similar spec epoxy-glass.". It is indeed a turret board, all be it a modern material as opposed to what was originally used.

The original poster on tdpri.com took an additional photo after he acquired a dentist's mirror and placed it under the board and it is clearly hand wired, as the image shows. There is no etched-in copper wire as would be the case if it was PCB.

Here's a link to the photo: https://www.tdpri.com/attachments/20...4-jpg.1206780/

JP

[JJP]

RT1 is an NTC thermistor in series with the incoming mains. The resistance is high on startup and drops as it heats up to normal operating temperature. The device has a temperature/resistance curve that gives a soft-start when turned on from cold. Fender has used these for quite a few years. The associated cap on that board is probably for noise suppression - needed these days for regulatory compliance.

Thanks for that explanation!

[JJP]

Well it's clearly handwired on eyelets. There are component "chalk lines" on the board and there may even be copper traces on the bottom side of that board. More likely Fender just did tidy under board bridges with lead wire but I don't know. Either way the build looks cool and I think it presents nicely along side "boutique" offerings. Kudos to Fender and their Pro Shop.

The original poster on tdpri.com provided an additional photo yesterday after he acquired a dentist's mirror and he slipped it under a section of the turret board and it is indeed hand wired, top to bottom.

https://www.tdpri.com/attachments/20...4-jpg.1206780/

[JJP]

I know this is obvious to most here, but for clarification:

A turret board has turrets standing up off the board.


An eyelet board has eyelets for connections (different from turrets).


A printed circuit board has neither- only through holes and built in traces so that wires are not required for most connections.


There is nothing wrong with any of these methods of building a circuit.

I believe I mistakenly use the words turret board and eyelet board interchangeably. Thanks for the clarification. The board in the '64 PR is clearly an eyelet board.

[JJP]

And here is an example of point to point construction, which uses no turret or eyelet boards, but may use terminal strips. Some people erroneously mistake point to point for 'hand-wired' which is I think the case for the guy who was griping about the Fender in that other forum.
Hand wired is pretty self explanatory, and could include any kind of construction. JCM800 used printed circuit boards which were hand wired to the tube sockets.

I think the only point to point wiring I've ever seen, is the inside of a Carr amp. He describes his build as "point to point", and he does not mention a turret board. Not sure if he still makes them the same?

[g1]

Yes, the models currently listed on the Carr website are described as 'hand wired point-to-point'.

[Tom Phillips]

Yes, the models currently listed on the Carr website are described as 'hand wired point-to-point'.

I don't see many Carr amps on my bench and the one's I have seen were made in 2004 or earlier.

Unfortunately, the workmanship seems to have deteriorated.
The attached photo is not dated but was recently presented in an on line discussion. It is not a good case for true point to point wiring.

[JJP]

I don't see many Carr amps on my bench and the one's I have seen were made in 2004 or earlier.

Unfortunately, the workmanship seems to have deteriorated.
The attached photo is not dated but was recently presented in an on line discussion. It is not a good case for true point to point wiring.

I was going to say something, but this is a total rat's nest. Is this a Carr amp? If so, I'd take the mass produced, flaws and all, Fender '64 PR any day. Mind you, there are a lot of other boutique builders out there who do great work. In my own, all be it limited experience, SWART comes to mind.

[The Dude]

This is strictly opinion, so you're free to disagree. I think point to point wiring makes sense in a small/simple amp with few gain stages (think Champ size or the like). Once you get to multiple gain stages, multiple PS nodes, channel switching, multiple channels, etc., etc.- it's no longer practical given currently available alternatives. That picture makes my head spin imagining having to build or repair the thing. It looks like some of my scrap parts boxes.

[DrGonz78]

Here’s one of my scrap parts build. It’s point to point with a secret turret board installed. I gutted a Hammond and just threw it together as I went. I didn’t draw a schematic of the circuit but it nothing unique. Sounds great too.