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Russ Andrews "Minizaps"
Russ Andrews "Minizaps"
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Old 19th October 2017, 08:46 AM   #1
Britain4 is offline Britain4
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Default Russ Andrews "Minizaps"

Here we go again with some more mysterious tweaks that I've nonetheless been curious to try out (but not enough to spend £145 on a pair!)

Having figured out the bones of the speaker Zapperators (they're based on a design a lot of people swear by and aren't really overpriced compared to the other options out there so fair play, although RA says there is more to their version) I'm wanting to try and uncover the secrets of the Minizap RCA plugs, another little tweak that seems highly mysterious but a lot of people absolutely swear by.

Not a lot of info on the RA site other than they are a "special version" of the Zapperator (silly name) that plugs into any unused outputs on the amp, of which I have four. So I would need £296 worth to cover my amp!

Now I cannot find any information at all about how these things work but I assume it involves a small cap, possibly an inductor and a resistor in the 8k range (to simulate the input impedance of a tape deck). Does anyone know if that will achieve what RA says it does (filtering out RFI noise at the outputs) and whether or not it will blow up my amp?

I know a lot of people here will roll their eyes at this stuff but I'm curious and I want to hear with my own ears whether it works or not

Last edited by Britain4; 19th October 2017 at 08:49 AM.
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Old 19th October 2017, 08:54 AM   #2
Mooly is offline Mooly  United Kingdom
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Russ Andrews "Minizaps"
Best option imo would be to study the output circuitry of the amp involved. You might conclude that a shorting plug is as good as anything.

Dangling an inductor across a line output sounds like a possible recipe to actually pick up certain types of interference. If the mysterious plugs present a low impedance then they could actually increase distortion unintentionally, particularly if the feed in question also feeds the main audio chain in use. If so, no shorting plug

A little knowledge can be a dangerous thing

Study your amp first and then make an informed decision.
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Old 19th October 2017, 09:25 AM   #3
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OK thanks for the reply!

I am a sucker for these things I know, I have to hear them (or not) before discounting them.

Shorting the outputs didn’t seem like such a hot idea until I remembered just now that there is a recording selector knob (which controls the tape outs) which is always set to “off” - when the selector is in this position the outputs are connected to ground via a 2.2k resistor (verified with a multimeter). Would love to know what’s in those Minizap things though, what sort of resistance would I need on the outputs to not blow the amp up?

Apparently they can also be used on the coaxial outputs on a CD player so I could put them to use there

Last edited by Britain4; 19th October 2017 at 09:50 AM.
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Old 19th October 2017, 10:19 AM   #4
DF96 is offline DF96  England
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£74 for a phono/RCA plug with a few components inside is having a laugh. There may, in some situations, be an argument for putting a Zobel network (RA calls these Zapperators) across the speaker terminals. Suitable components would cost a few £ at most (RA charges £134 - more laughing). I can think of no good reason to put anything across an unused output. I can think of no good reason to spend £74 for something which is not necesssary amd could be made for a few £.

The secret of these items is that they are a hugely efficient economic transfer device.
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Old 19th October 2017, 10:26 AM   #5
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Quote:
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£74 for a phono/RCA plug with a few components inside is having a laugh. There may, in some situations, be an argument for putting a Zobel network (RA calls these Zapperators) across the speaker terminals. Suitable components would cost a few £ at most (RA charges £134 - more laughing). I can think of no good reason to put anything across an unused output. I can think of no good reason to spend £74 for something which is not necesssary amd could be made for a few £.

The secret of these items is that they are a hugely efficient economic transfer device.
Indeed, £74 is absolutely ridiculous for one of these things. Reportedly they work but not only can I not afford to spend nearly £500 on these things for each set of unused outputs (!), even if I could I would begrudge doing so knowing they just have a few small components inside.

What I am trying to find out is what those few components are, if they’re based on the speaker Zap circuit as he says they are then I am assuming basically a cap and resistor but I don’t know what value resistor would be safe for any output (Rec out on the amp and digital out on the CDP).

I think that’s pretty much it in a nutshell
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Old 19th October 2017, 11:06 AM   #6
DF96 is offline DF96  England
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As nothing at all is needed across an unused output I suggest a suitable approximation to nothing would be a 1M resistor in series with a 2.2pF capacitor. Alternatively, just use a plug with nothing in it. They cannot work because there is nothing for them to do. Their function is economic (and emotional), not electrical.

The speaker version will use rather different values.
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Old 19th October 2017, 11:52 AM   #7
Mooly is offline Mooly  United Kingdom
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Russ Andrews "Minizaps"
Just out of curiosity... what is the amplifier in question ?
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Old 19th October 2017, 02:17 PM   #8
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Quote:
Originally Posted by DF96 View Post
As nothing at all is needed across an unused output I suggest a suitable approximation to nothing would be a 1M resistor in series with a 2.2pF capacitor. Alternatively, just use a plug with nothing in it. They cannot work because there is nothing for them to do. Their function is economic (and emotional), not electrical.

The speaker version will use rather different values.
Yes duly noted, I think it’s just the satisfaction of building these things for myself for a fraction of what he charges thanks for the idea of where to start with it, reading the RA website has me worried I’m losing musicality without them

The amp in question is a Pioneer A400 which I have been modifying over the last couple of weeks, turning it into a really lovely sounding amp with less of the harshness they are known for.

CDP is a Marantz CD63 for which I am following this guide Marantz CD63 Basic upgrade overview / guide - has really benefitted from a few basic mods so far and I have a long way left to go with it.

As a side note the amp does pick up an amount of noise from inputs which are not selected - I can listen to my CD player from any of the other inputs if I turn the volume up far enough! Hopefully this will be taken care of with the shorting plugs I’m going to be using on the inputs (made by myself of course. Ordered a big pack of RCA plugs for cheap. Silly me had a senior moment and bought red and black ones thinking I would need to colour code them )

Last edited by Britain4; 19th October 2017 at 02:30 PM.
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Old 19th October 2017, 02:29 PM   #9
Mooly is offline Mooly  United Kingdom
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Russ Andrews "Minizaps"
The Pioneer A400 uses a 'passive preamp' and so each record output switch simply places that tape output in parallel with the selected source.

There is a 2k series feed to each output.

So if you select record output 1 and 2 to be both CD, then both outputs are placed in parallel with the CD input sockets.

If you load the record outputs in any way, that load appears as a load across the selected source (CD in our example).

If you set the record selector to OFF then all output feeds are grounded and disconnected from the inputs.

That is the best option. Set to OFF. Job done.
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Old 19th October 2017, 02:31 PM   #10
Britain4 is offline Britain4
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Quote:
Originally Posted by DF96 View Post
As nothing at all is needed across an unused output I suggest a suitable approximation to nothing would be a 1M resistor in series with a 2.2pF capacitor. Alternatively, just use a plug with nothing in it. They cannot work because there is nothing for them to do. Their function is economic (and emotional), not electrical.

The speaker version will use rather different values.
Yes duly noted, I think itís just the satisfaction of building these things for myself for a fraction of what he charges

The amp in question is a Pioneer A400 which I have been modifying over the last couple of weeks, turning it into a really lovely sounding amp with less of the harshness they are known for.
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