Thermistor vs Standby Switch in Reverb/Vibe Unit?

[bcmatt]

So, I've been hankering to build this Reverb/Vibrato Circuit for a long time now, and I feel I am getting close as I try to source all the parts to do so.
[img:4421:1870]http://taweber.powweb.com/store/5h15_layout.jpg[/img]
[img1593]http://taweber.powweb.com/store/5h15_schem.jpg[/img]
I wasn't interested in building the kit, but if it ends up being significantly cheaper even though I already have a chassis I could use, I might do that.

Anyways, what is the deal with a thermistor? Is it just to make startup safe on the tubes since there is no rectifier tube or standby switch on this circuit? If I just use a standby switch, can I avoid having to search the internets and order this part from some random place other than my regular one-stop web order (AES)?

Anyone else tried this combo circuit? (6G15 with 6G12vibrato)
Since I primarily use my EH Holy Grail and EH Wiggler as my two most common pedals, I figure I could replace them both with this one unit that should sound way better...
https://taweber.powweb.com/store/Revibe.mp3
Looks like I may be forced to go through Weber for the transformers though, since the PT needs more current to power the extra tubes.... Thoughts?

[tictac]

The thermistor is the Weber way of simulating the slow warm up of a tube rectifier, which in reality it doesn't really do very well. It is not needed, neither is a standby switch. There's no reason for slow warm up at these low voltages.

A thermistor is nice to have after the primary fuse to prevent a high current in-rush on larger amps, but again not needed in a low power low voltage device like this....

TT

[tictac]

One other thing...

The power switch in your schematic is wired incorrectly. The first thing that should be connected to incomming AC voltage is a fuse not a power switch.

Put the fuse on the 120V AC Line first and the switch after the fuse wired in series. This way if the switch fails the fuse will blow and protect the user from becoming a ground path for AC current...

TT

[bcmatt]

The thermistor is the Weber way of simulating the slow warm up of a tube rectifier, which in reality it doesn't really do very well. It is not needed, neither is a standby switch. There's no reason for slow warm up at these low voltages.

A thermistor is nice to have after the primary fuse to prevent a high current in-rush on larger amps, but again not needed in a low power low voltage device like this....

TT

Good to know. Thanks very much. I was thinking of doing a 3 positions switch before, but I guess I'll just use a single spst.

One other thing...

The power switch in your schematic is wired incorrectly. The first thing that should be connected to incomming AC voltage is a fuse not a power switch.

Put the fuse on the 120V AC Line first and the switch after the fuse wired in series. This way if the switch fails the fuse will blow and protect the user from becoming a ground path for AC current...

TT

Also good to know. I shall make the change on my build accordingly.

[Diablo1]

The thermistor is the Weber way of simulating the slow warm up of a tube rectifier, which in reality it doesn't really do very well. It is not needed, neither is a standby switch. There's no reason for slow warm up at these low voltages.

A thermistor is nice to have after the primary fuse to prevent a high current in-rush on larger amps, but again not needed in a low power low voltage device like this....

TT

Doesn't the thermistor slow the high current inrush to charge the 100 mfd cap?

[Koop]

One other thing...

The power switch in your schematic is wired incorrectly. The first thing that should be connected to incomming AC voltage is a fuse not a power switch.

Put the fuse on the 120V AC Line first and the switch after the fuse wired in series. This way if the switch fails the fuse will blow and protect the user from becoming a ground path for AC current...

TT

I see what you mean on the schematic, on the layout it appears to be correct though.

[Diablo1]

You should also consider and compare the Tore-Vibe to the Re-vibe. In either case, I doubt there is any advantage to sourcing your own components. It's very hard to beat the Weber kit price on these. I built the Tore-Vibe with only one simple mod to reduce the gain so the reverb stayed clean.

[tictac]

Doesn't the thermistor slow the high current inrush to charge the 100 mfd cap?

Why would you need to do that?

[bcmatt]

You should also consider and compare the Tore-Vibe to the Re-vibe. In either case, I doubt there is any advantage to sourcing your own components. It's very hard to beat the Weber kit price on these. I built the Tore-Vibe with only one simple mod to reduce the gain so the reverb stayed clean.

Ya, the vibe circuit as opposed to regular tremolo is what appeals to me. That's why I like the wiggler so much is because it does vibrato as well and I use that almost exclusively. So, the Revibe seems for me. Also, when comparing the sound-clips of the two on the weber site, the revibe is what I like.

I'm going to price out the components that I don't already have and see what comes out cheaper; kit or self-sourcing.

[bcmatt]

I'm going to price out the components that I don't already have and see what comes out cheaper; kit or self-sourcing.

Well, it looks like sourcing the parts I need myself would save me about $150.

I have a good chunk of the resistors, caps, switches and jacks already as well as a chassis that I can adapt into this. Since I'll have to build my own cab anyways, it will give me a little more sense of pride (I know I'm weird) to have built the whole thing myself without a kit. I like doing weird stuff like wooden faceplates, and such anyways.

There are a few unusual things I wonder about though...

The Output Transformer that weber uses for this kit says that has a primary of 7k but just a 4 ohm secondary. However, the reverb pan is an 8ohm input. Is that normal for reverb units, or should I get the multi-tap (or some other) OT with an 8 ohm secondary for $5 more?
http://taweber.powweb.com/store/magnetic.htm
The sell Heyboers to for $5 more...

What's the deal with that weird little brass pipe? Is that common instead of a copper ground bus?
[img:914:686]http://www.tedweber.com/revibe/rv-7.jpg[/img]

Then there is the Weber choke that is 9H at 120. Is that a big deal that it seems to be more H than the Fender was?