A couple quick questions

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surfsup
Posts: 1513
Joined: Mon Nov 29, 2010 12:21 am
Location: Chicagoland

A couple quick questions

Post by surfsup »

As I learn the input jack and output jacks are still confusing me. Three questions...

is my input wired right?
s my output wired right?
can I run my output jack ground line to my IEC ground? (the PT ground area is pretty crowded!)

[img:1082:750]http://chicagocadcam.com/ChrisHahn/schem/03.jpg[/img]
[img:1002:600]http://chicagocadcam.com/ChrisHahn/schem/01.jpg[/img]
[img:600:1002]http://chicagocadcam.com/ChrisHahn/schem/02.jpg[/img]
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Phil_S
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Location: Baltimore, MD

Re: A couple quick questions

Post by Phil_S »

The IEC mains ground is always by itself. Never mix any other ground with it. Think about what you are doing. If you run a circuit ground back to the mains, your amp is no longer isolated and that defeats all safety measures. It will also hum like a <favorite bad word here> from being linked to the mains.

I'm a bad judge for looking a pictures of wired jacks. The sleeve is always near the chassis on a Cliffs type jack and the tip is away from the chassis. The ground goes to sleeve. The tip is hot -- your 4-8-16 ohm output leads, or the connection to the V1 grid (or grid stopper) for input. Here are some drawings that should help with your input jacks. Remember to check what is switched and what is not. On some knock off Cliffs type jacks, the switch is reversed. Cliffs are "break" type switches, so the one that lifts is not the switch.
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selloutrr
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Re: A couple quick questions

Post by selloutrr »

picture one input jack is wired wrong. currently you make tip contact to ground at all times.

stick an instrument cable in and set your DVM to beep and test tip to tip / tip to ground... BEEP..

take your ground from the constant side on the Sleeve lug (closest to the chassis.)
Wire the resistor across to the switching side up to the TIP switching side. so that when closed the tip is shunted to ground through the resistor.


Picture 2 is fine as long as you can confirm you soldered to the constant and not the switching side.
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Ian444
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Location: Australia

Re: A couple quick questions

Post by Ian444 »

I think the top left hand contact on the upper hi-gain input jack is the one that breaks when the plug is inserted. Same for the lo-gain jack below it. When the lo-gain jack is used the upper jack completes the 68K/68K voltage divider.
surfsup
Posts: 1513
Joined: Mon Nov 29, 2010 12:21 am
Location: Chicagoland

Re: A couple quick questions

Post by surfsup »

Guys, thanks. I have only one input jack. In the photo the 1MR is soldered from tip to sleeve, then the lead goes diagonally (hard to see) to the other tip, where it is grounded to chassis. I assumed all these jacks were made the same with (in my photo) the top teft tip always being connected to ground.

The problem is I don't know which side is switching...and didn't check. Since its all soldered in, how can I test while they are installed? Sellout wouldn't that only work if the resistor/grounds weren't already soldered? (I don't have any more of these laying around)
surfsup
Posts: 1513
Joined: Mon Nov 29, 2010 12:21 am
Location: Chicagoland

Re: A couple quick questions

Post by surfsup »

Just found this, for reference, which is how I have mine wired but as mentioned, I am not sure if the switching pin is reversed:

[img:324:310]http://www.ampmaker.com/images/ak01kit/ak01cw3.jpg[/img]
[img:324:259]http://www.ampmaker.com/images/ak01kit/ak01cw5.jpg[/img]

I will run my OT/speaker ground to the ground lug I ran all my other stuff to, but I saw this on ampmaker as well, a short speaker ground lead to the chassis:
[img:324:257]http://www.ampmaker.com/images/ak01kit/ak01cw19.jpg[/img]
Ian444
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Joined: Mon Nov 22, 2010 10:19 pm
Location: Australia

Re: A couple quick questions

Post by Ian444 »

surfsup wrote:Just found this, for reference, which is how I have mine wired but as mentioned, I am not sure if the switching pin is reversed
You could test your guitar input socket like this - with power off, plug a guitar lead into the input socket. Measure the resistance between the tip and sleeve of the plug on the other end of the guitar lead. If it is around 1 megohm, then all is fine, if it is say around 1 to 5 ohms then the switch is reversed, and you will get no guitar signal into the amp.
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