Use pin connectors or replace with new output jacks?
Apr 4, 2006 at 3:11 PM Thread Starter Post #1 of 18

proglife

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I have a Pioneer SA-8100 from 1973/74 that I run into a pair of EPOS ELS-3's. I have some Canare 4S11, techflex and heatshrink on the way and plan on using spades on the Epos monitors. The Pioneer has those clip style/pin speaker outs.

My question is: Should i just use pins on the other end of the Canare (is this even possible with the gauge of the 4S11?) or replace the speaker outs with something like WBT posts? I've never done anything like that, but the amp was free and it could be a fun project to get my feet wet with.

I plan on moving the amp to that space in between the banister and the end of the couch...probably on a small stand to match my future coffee table.

upstairs.jpg
 
Apr 4, 2006 at 5:57 PM Post #4 of 18

rickcr42

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Since this is the DIY forum I have to suggest getting rid of the pin connectors and putting a better/more substantial connector in its place.

The contact area and coneection integrity is SO BAD with a pin connection anything over lamp zip cord for speaker cables is a total waste of money.

Usually the easiest way it to totally remove the clip lead assembly which should leave a square hole and replace it with a equal sized strip og G-10 fiberglass (pcb material) having binding posts in place of the clips.Drilling holes in the same spot as the former clip assembly you can even use the old hardware to mount the new


...or do what I do and drill new holes and use feed through barrier strips for the connections
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Apr 4, 2006 at 7:14 PM Post #6 of 18

proglife

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Quote:

Originally Posted by rickcr42
Usually the easiest way it to totally remove the clip lead assembly which should leave a square hole and replace it with a equal sized strip og G-10 fiberglass (pcb material) having binding posts in place of the clips.Drilling holes in the same spot as the former clip assembly you can even use the old hardware to mount the new


Great...that's really what I would like to do. I'm itching to put my unused soldering iron to use and I think this would be a worthwhile/simple project to start with. If the amp gets fried, no big loss.

Thanks for the replies! One more question: Can anyone think of a good resource off-hand that would point me in the right direction? Anything that shows (visually) how to replace output jacks would be great. It doesn't need to be anything specific, simple photos of the internal end of amplifier output jacks would be great (installation photos would be a bonus).

Thanks again!

P.S. This is what you see when you walk in my front door. The new cables should clean things up a bit as they will allow me to move that amp out of the middle of the floor.

stairs.jpg
 
Apr 4, 2006 at 7:45 PM Post #7 of 18

rickcr42

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You could probably do a google search on "Dynaco ST-70" then go to the "images" tab for ideas.This is maybe the most common upgrade for older amps that used the old "screw terminal strip" type speaker connectors which work better than 80% of modern connectors but are not much good for attaching some of the designer spades and not being gold (tin plated) tarnish.

A "quick and dirty" version would be to pull the clip terminals.measure the mount and cut a piece of pcb material (without copper !) to the same size and using the monting holes as guides for the new holes so they line up,then use a "dual binding post" which already has the proper spacing for using speaker conntectors,cut the holes,mount the posts then mount the assembly and wire it up
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BTW-I personally would not get hung up on fancy binding posts but use a good qwuality heavy duty one like this

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no matter what you read the expensive "boutique" parts do not work better,sound better or even last longer but they WILL cost you more.
 
Apr 4, 2006 at 7:51 PM Post #8 of 18

proglife

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Dyanco ST-70...excellent. Thanks!

Yeah, I have no intentions of buying anything exotic. I plan on trying to screw around with this thing until I learn or break something.
 
Apr 4, 2006 at 7:54 PM Post #9 of 18

rickcr42

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Quote:

Yeah, I have no intentions of buying anything exotic. I plan on trying to screw around with this thing until I learn or break something.


Pretty much what we all did,at least the ones who did not get "fried" during the "I want to learn" stages


bzzzzzzzzt

watch those fingers man
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Apr 5, 2006 at 2:57 AM Post #10 of 18

proglife

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I opened this thing up tonight. Built like a frikkin' tank. Vintage electronics are so cool and manly
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http://derdock.net/pioneer_sa8100/

looks like a possibly easy job replacing the spring terminals? I'd also like to bypass the second pair of speaker outs. I have no use for them.

Does anyone see anything else in there that would be relatively easy to replace and possibly worth it? I'd love to take all the stuff that I don't use out of the chain...like the subsonic filter, the complicated tone controls, etc.

Any thoughts?
 
Apr 5, 2006 at 3:01 AM Post #11 of 18

rickcr42

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Quote:

I'd love to take all the stuff that I don't use out of the chain...like the subsonic filter, the complicated tone controls, etc.


better to have tone controls that can be defeated and not need them than to need tone adjustment and not have a means is my opinion.
The subsonic filter same thing.A MUST if you have a turnatable or plan on getting one ever and again,my opinion,a low cut is essential for every system so just a matter of where and how steep
 
Apr 5, 2006 at 3:24 AM Post #12 of 18

proglife

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Quote:

Originally Posted by rickcr42
The subsonic filter same thing.A MUST if you have a turnatable or plan on getting one ever and again,my opinion,a low cut is essential for every system so just a matter of where and how steep


oh, is that the purpose of that function? I totally misassumed what it was for. This thing was built before I was born
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I had 2 or 3 LPs until the parents bought a tape deck.
 
Apr 5, 2006 at 3:38 AM Post #13 of 18

Garbz

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Sorry to chime in and de-rail this thread slightly. But the subsonic filter, that's to stop the very low frequency flutter on the speakers of the vinyl isn't it? I have a problem like that since my phono stage doesn't actually stop rising below 20hz :S It's fine with speakers since i've never had it hit the max excursion but with headphones it puts preassure on the ears.

So this form of subsonic filtering is simply a high-pass filter tuned in the vicinity of 20hz isn't it?
 
Apr 5, 2006 at 4:08 AM Post #14 of 18

proglife

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It says "30 hz" on the switch, but it has to be much higher than that...or maybe the crossover slope is super steep and I have better hearing than i thought.

To my ear, it sounds like it cuts out 125-150hz and below. It's very distinct with my Epos monitors.
 
Apr 5, 2006 at 4:28 AM Post #15 of 18

rickcr42

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Quote:

I have a problem like that since my phono stage doesn't actually stop rising below 20hz :S It's fine with speakers since i've never had it hit the max excursion but with headphones it puts preassure on the ears.


You NEED a low end cutoff in a vinyl based system with it usually being around 15-18 hz depending mostly on how steep the slope is or you can end up with serious system problems.One is if your speakers for instance have ports and don't dare drop the stylus to the disc
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.

the good news is if you have a DC blocking cap you already have a single pole high-pass filter.The bad news is being low in frequency and only a single pole the rolloff rate is so slow it does very little to the actual subsonic energy so either the pole needs to be raised or you need to cascade more stages and watch your phasing.

-6db single section is "in phase" but a -12dB is "reverse phase" which again becomes phase correct at -18dB per octave

Quote:

It says "30 hz" on the switch, but it has to be much higher than that...or maybe the crossover slope is super steep and I have better hearing than i thought.


usually receivers of the era had a multiposition filter but if yours is 30 hz or nothing then it means -3dB @ 30hz which is also -1.5dB @ 60hz and -0.75db @ 120 hz.
If you want to keep the filter but lower the dominant pole just double up the capacitor values and you will shift it to 15hz
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