OD/Clean

[martin manning]

Matt, I had pasted the wrong link for a 240VAC mains PT from Tube Amp Doctor above... it's fixed in the edited version. I don't think anyone except somone wanting an accurate #124 reproduction would use slide switches. Mini toggle switches are the standard. The 5-pin XLR is in the same class. A 5-pin DIN will be less expensive and will work with production cable assemblies.

[halfbackstrat]

Thanks Martin, the XLR socket is about £11. I'll have a look and compare the DIN.
I'm building on the C&E pedals Chassis. These don't have the socket for the 1-N-2 switch, but i'm a little unclear on what the 1-N-2 switch is for, and looking at the circuit diagram, i can't see what purpose it serves.

[martin manning]

The C&E chassis is cut for a Switchcraft DIN jack, like Mouser PN 502-57HB5FX, which will accept a standard MIDI cable. 502-57HA5FX accepts a Marshall footswitch cable. The 1-N-2 switch is to connect a cap from one side or the other of the mains to ground. This is a holdover from Fender designs, and is considered unsafe since if the cap shorts the chassis could be at mains potential. The CE chassis does not have provision for that feature... it's called a "death cap" here.

[halfbackstrat]

Makes sense! So what's the alternative to build a safe amp? I'm looking at your layout just now for the power section and i'm not seeing a switch like the 1-N-2 one.

Also Martin i've been listening to your amp sound clips on VVT, they sound great! I have Fralin Vintage Hot PUPS in my strat.

[martin manning]

Not my clips, but I'm sure Tony's amps sound fantastic. I only helped with the layout drawing; Tony was very generous to give me top billing.

Most people leave the ground switch out, or put it in but leave it unconnected for cosmetics. It's really not needed with a properly grounded and polarized mains connection. My #124 in a C&E chassis using jborder's board set is here: https://tubeamparchive.com/viewtopic.ph ... highlight= Scroll down for more gut shots.

[halfbackstrat]

Ah my mistake, thanks for this Martin, i can't tell you how helpful you've been and thank you enough. I will be sure to post an extensive build report on the forum in an attempt to return something to the forum.
I feel bad taking so much knowledge and having little to return (for the moment)

[Structo]

Tom, the difference in your wiring is in the amp, rather than the footswitch, I believe. The way you have it would be useful- it'll tell you from the footswitch if the manual switch is on.

Well it's not unheard of for me to make a mistake but I'm pretty sure I have the rear panel switches wired the same as #124.
I have two SPDT On-On toggle switches.
So I am not arguing, just trying to understand if my amp is built right.

Wired like below but I added the ground wire that is missing on the original layout and it's noted on the drawing below.

The footswitch itself is wired like the one below, the 3 switch one.

The Ampdoc wiring looks like it would do as you describe because of the series wiring on it.

But having it wired as below turns on the LED's on the footswitch when the rear panel switch is thrown.

The only thing I did different was to run only one hot + wire to the footswitch instead of two like #124 has.

[halfbackstrat]

Point of Enquiry, are Vishay/Sprague Orange Drop Polyester Film Capacitors a good substitute for polystyrene Orange Drops?

[Structo]

I don't think any of the orange drops are polystyrene.

The caps that were used by Dumble were mainly the 6PS polyester, 600v.

These are the round, radial type.

If you look here, you can see how many different types there are but mainly there is two dielectrics, polyester and polypropylene.

There are also the 225P and 418P polyester caps but you don't see many of those.

http://orangedrop.sbelectronics.com/product_specs.html

[halfbackstrat]

Man these things are hard to find haha

For 0.005 micro farad caps, the closest values are 0.0047 and 0.0056.
Whats the general rule for these situations?

[martin manning]

Tom, the difference in your wiring is in the amp, rather than the footswitch, I believe. The way you have it would be useful- it'll tell you from the footswitch if the manual switch is on.

Well it's not unheard of for me to make a mistake but I'm pretty sure I have the rear panel switches wired the same as #124.
I have two SPDT On-On toggle switches.
So I am not arguing, just trying to understand if my amp is built right.

Wired like below but I added the ground wire that is missing on the original layout and it's noted on the drawing below.

The footswitch itself is wired like the one below, the 3 switch one.

The Ampdoc wiring looks like it would do as you describe because of the series wiring on it.

But having it wired as below turns on the LED's on the footswitch when the rear panel switch is thrown.

The only thing I did different was to run only one hot + wire to the footswitch instead of two like #124 has.

The Ampdoc/BN diagram has the panel and footswitch switches in parallel, so either one will energize the relay and illuminate the LED. The #124 layout snip shows the original, where the panel switch either grounds the relay coil directly (so no LED), or it switches the relay coil lead over to the footswitch jack, where the footswitch will ground the relay coil and turn on the LED. Note that all three lugs of the switch are used in the #124 (SPDT), whereas on the BN drawing only two are used (SPST).

[hans-jörg]

Hi,
I gave the former (because useless to have 2 of them) PAB switch at the back the "chance" to switch my RNFB from V1. The right switch at the right place for that IMO

Hans-Jörg

What I wanted say is: if you have the rock/Jazz switch in front, you dont need it at the back (therefore RNFB, see above).
As I understood this 2 switches (rear) been there before the skyliner update of HAD. Means - there was no 3 way switch on front. But now, PAB is switchable from front you can fix the wires for PAB footswitch direct to footswitch connestor at the reare. I recogniced it late, so I had there 2 of them. Useless (the second) therefore I switch now with it the RNFB at V1.
So: this rear PAB switch is not neccessary for functionality of footswitch.
If you want to sitch it from the rear (whatfore? you have it on the front) you need for shure the ground contact at the switch (but only for the PAB switch), not for the footswitch! As I said, absolutly no reason for it.

God, so many switches ...

I hope everybody cought my thoughts. My english is terrible

Hans-Jörg

[Structo]

The Ampdoc/BN diagram has the panel and footswitch switches in parallel, so either one will energize the relay and illuminate the LED. The #124 layout snip shows the original, where the panel switch either grounds the relay coil directly (so no LED), or it switches the relay coil lead over to the footswitch jack, where the footswitch will ground the relay coil and turn on the LED. Note that all three lugs of the switch are used in the #124 (SPDT), whereas on the BN drawing only two are used (SPST).

It must be the way I have my footswitches wired because I have the amp wired just like #124 except I used toggle switches so the terminals are reversed from the slider switch.

Thanks for the great explanation!

My switches work so I guess that is a small miracle in itself.

[Joost]

Hi Structo,

So will the PAB switch not work without the ground?

I should add that when you turn those back panel switches on, they actuate the relays.
So if you have LED's on the footswitch, they will light up as if the footswitch was pressed when you use the back panel switches.

The back panel switches can help if you have to trouble shoot and you don't feel like plugging the footswitch in or other reasons.

Also, the PAB switch is not wired to where it will work right as shown in the #124 layout.
There is a ground missing on the PAB switch.
Here is a layout that I have edited a few things.
Check out the OD/PAB switches to see what I mean.
Remember that #124 has slide switches, not toggle switches.
So for toggle switches, you would flip the wires on the terminals.
In other words the ground goes on the bottom terminals.

On my amp I put the Mid Boost on the footswitch as well.

[hans-jörg]

Hi,
thats right. But footswitch works - if plugged in.

Hans-Jörg