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ampeg v-4 question.

Posted: Wed May 11, 2016 1:50 am
by waltdogg
which jacks need to be isolated from the chassis and which ones don't? i've got a lot of conflicting information from many techs, can't seem to find anything with a quick google search. i was finally gonna replace the weak looking power cable my first tech had put on it then i realized i should do a few other simple things while it's open. i.e. check my input and output isolation. anyways. anyone know?

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 2:02 pm
by waltdogg
anyone?

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 2:18 pm
by SquareWaveFuzz
Ideally, all of them, but I don't know what the grounding scheme is in a V4 so don't know how feasible that would be so that's probably not a great deal of help

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 2:23 pm
by waltdogg
hmm. well i'm going to be using these washers: https://tubedepot.com/products/isolatio ... t-shoulder

yeah the ground ampeg uses is fucking weird. i'm just undoing and redoing the power cable by a picture. i don't wanna venture any guesses or leave it to the peanut gallery.

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 3:30 pm
by waltdogg
*somewhat* reliable sources claim it's just the speaker output jacks.

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 6:53 pm
by Faldoe
Do you have the original ones to compare?

Also, check out this forum. The guy that ran/still runs
Ampegv4.com started this one.

http://www.vintageampeg.com/forum/

Re: ampeg v-4 question.

Posted: Wed May 11, 2016 7:36 pm
by waltdogg
i doubt whatever i've got in there now as isolation washers are even the proper type.

i'll find out when i open up the amp later in the week.

Re: ampeg v-4 question.

Posted: Thu May 12, 2016 9:40 am
by Adamadamadam
Isolating all the jacks shouldn't do any harm, but I've never poked around inside a V4. I've never used the shoulder washers from tube depot and they're probably fine, but if those don't work switchcraft makes one. It's switchcraft part S4263.

Is the polarity switch/grounding cap assembly still hooked up? Removing it from the circuit is super quick, eliminates a potential source of noise, and just makes sense if you're using a 3 prong cord.

Re: ampeg v-4 question.

Posted: Thu May 12, 2016 9:41 am
by D.o.S.
Kiss Kiss Bang Bang!

Re: ampeg v-4 question.

Posted: Thu May 12, 2016 10:01 am
by Adamadamadam
Yep. It was really hard to narrow it down to one gif.

Re: ampeg v-4 question.

Posted: Thu May 12, 2016 12:15 pm
by SquareWaveFuzz
waltdogg wrote:*somewhat* reliable sources claim it's just the speaker output jacks.
Definitely isolate the speaker jacks, isolating the others is more for noise reduction and only really makes sense if you're also going to redo the entire grounding scheme

Re: ampeg v-4 question.

Posted: Thu May 12, 2016 2:47 pm
by waltdogg
got it.

i think the ones tube depot are selling are the switchcraft ones. different parts numbers though.