# Some Audio Advice Needed



## ossian (Nov 8, 2016)

I am hoping that there are some audiophiles on here. Or musicians. Or both! As I need some advice on audio cables.

I am planning on building a thing for a guitar amp called an attenuator. Basically this device sits between the amp and its 12" speaker. It allows the player to reduce the output volume of the amp without affecting the quality of sound too much. A guitar amp needs to be driven hard to allow it to 'break up' and distort. Simply reducing the amps' volume does not allow this to happen. Hence the need for an attenuator.

Now, what I need to know is what type of audio cable is suitable for connecting to the attenuator pod inside the device and, at the other end, to a standard mono 1/4" jack plug which will plug into the amp's speaker socket. It does not need to be shielded cable like a guitar instrument cable.

So does anyone here have any idea what type of cable would suit this?


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## mathjak107 (Nov 8, 2016)

any shielded audio cabling is fine .  i would use a fairly larger size cable depending on amperage and length


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## HazyDavey (Nov 8, 2016)

I've always used speaker cables (not guitar cables) when running external cabinets from my guitar amp. They come in different lengths with 1/4" male ends. Good luck and I hope you fine a great tone.


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## ossian (Nov 8, 2016)

mathjak107 said:


> any shielded audio cabling is fine .  i would use a fairly larger size cable depending on amperage and length


Do you think it needs to be shielded? I thought for speaker cables that was not required and it was what differed from guitar cables.


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## ossian (Nov 8, 2016)

Hazy Davey said:


> I've always used speaker cables (not guitar cables) when running external cabinets from my guitar amp. They come in different lengths with 1/4" male ends. Good luck and I hope you fine a great tone.


I could do that, Davey, by building an output socket into the attenuator box. But I wanted to avoid that by cabling up direct to the attenuator pod inside the box and fitting a jack to the end of the cable. So, one input for/from the amp and one cable/jack plug to the speaker socket on the amp. (I hope that makes sense!)


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## Capt Lightning (Nov 8, 2016)

Does nobody use a '"fuzz box" these days, or does that not produce the desired effect?

I wondering at which point in the amp that the distortion / clipping occurs and if could be controlled by fiddling with the amount of negative feedback?


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## ossian (Nov 9, 2016)

Capt Lightning said:


> Does nobody use a '"fuzz box" these days, or does that not produce the desired effect?
> 
> I wondering at which point in the amp that the distortion / clipping occurs and if could be controlled by fiddling with the amount of negative feedback?


I have used 'fuzz' pedals in the past but don't like them too much. I do occasionally use drive and other distortion pedals but that is not really what I am after. Using a drive pedal and keeping the volume low on a clean setting does not give the same affect as a driven amp at a lower, attenuated volume. A drive pedal tends to 'colour' the tone.


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## Capt Lightning (Nov 9, 2016)

I'm rather out of the loop these days.  I used to work at weekends in a music shop repairing amps, keyboards etc...  and build 'fuzz boxes' too.
I suspect it's the nature and degree of the harmonics produced when you over-drive the amp.

Are you in a band?  I used to play bass (badly) in a blues band in my student days.  We were pretty awful, although a couple of friends from those days did go on to be modestly successful.  One has gone back to his 'roots' and still tours on the folk circuit.


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## ossian (Nov 9, 2016)

Capt Lightning said:


> I'm rather out of the loop these days.  I used to work at weekends in a music shop repairing amps, keyboards etc...  and build 'fuzz boxes' too.
> I suspect it's the nature and degree of the harmonics produced when you over-drive the amp.
> 
> Are you in a band?  I used to play bass (badly) in a blues band in my student days.  We were pretty awful, although a couple of friends from those days did go on to be modestly successful.  One has gone back to his 'roots' and still tours on the folk circuit.


No I am not in  band, Capt. I did play a couple of acoustic gigs back when I was a teenager but did not do anything beyond that. I learned and played classical guitar for most of my time after I turned 20 but about 10 years back got into electric.I now play mostly blues and blues/rock.

This is my first attempt at bulding anything seriously. The design of the attenuator is quite simple and I should manage it. However, I did wonder about the cable quality required for a speaker. When I was a kid, we did not bother about such detail. I remember using old remnants of domestic cable to connectb speakers and they seemed to work fine. 

On the amp distortion thing. A decent amp will stay 'clean' up to a pretty high output level, but beyond that it will start to break up and produce some distortion. That tends to be the tone that we mostly recognise on rock and blues guitar sounds. You should be able to control that with your guitar volume. Rolling it off a little will clean up your tone, pushing it up will distort it. However, the problem in the home is managing to achive this while not detroying your eradrums!!! I use a 20W amp which gets pretty loud when cranked up. So...... the attenuator should sit between the power stage of the amp and the speaker and allow me to reduce output without losing too much of the tone. Simply turning down the volume on the amp or introducing a master volume pedal does not achieve that.

That is a simple, uneducated explanation and I have probably got some of it wrong. But you may follow what is going on.


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## HazyDavey (Nov 9, 2016)

ossian said:


> I could do that, Davey, by building an output socket into the attenuator box. But I wanted to avoid that by cabling up direct to the attenuator pod inside the box and fitting a jack to the end of the cable. So, one input for/from the amp and one cable/jack plug to the speaker socket on the amp. (I hope that makes sense!)



I think I understand, ok well maybe just buy the speaker cable and work from there. It comes in three sizes that I know of, 12, 14, and 16 gauge, 12 gauge would be the thickest. We ran all our PA speakers and monitors using 20 foot, 16 gauge cables and it worked fine. I also used 16 gauge cable with my bigger amp and two speaker cabinets. I'm thinking 12 gauge is handy when using much longer cables but I'm not sure.

I've read about attenuators but never seen or used one. I'm curious how'll you like it, and I hope I helped a little. Good Luck !!


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## Capt Lightning (Nov 9, 2016)

Out of interest, what's in the 'attenuator' ?  Are you using a simple resistive one or is it more fancy than that?  Is it going to be variable?
I did a degree in Electrical & Electronic engineering at Uni, but that was a long time ago.


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## ossian (Nov 9, 2016)

Hazy Davey said:


> I think I understand, ok well maybe just buy the speaker cable and work from there. It comes in three sizes that I know of, 12, 14, and 16 gauge, 12 gauge would be the thickest. We ran all our PA speakers and monitors using 20 foot, 16 gauge cables and it worked fine. I also used 16 gauge cable with my bigger amp and two speaker cabinets. I'm thinking 12 gauge is handy when using much longer cables but I'm not sure.
> 
> I've read about attenuators but never seen or used one. I'm curious how'll you like it, and I hope I helped a little. Good Luck !!


You did indeed. I had been looking at 16 gauge wire and from you say, it sounds like I could indded use that. Many thanks.


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## ossian (Nov 9, 2016)

Capt Lightning said:


> Out of interest, what's in the 'attenuator' ?  Are you using a simple resistive one or is it more fancy than that?  Is it going to be variable?
> I did a degree in Electrical & Electronic engineering at Uni, but that was a long time ago.


It is a variable, resistive attenuator. There is not much to it. It uses an 8 ohm 100W L-pad and has a couple of switches. On/off bypass switch. A treble switch giving 2 levels of treble lift. And, of course, an input and output jack. The L-pad is completely variable like a master control - not preset reduction levels.

I have no knowledge of electronics at all! :what1: So this is really my first serious attempt at this sort of thing. But I am doing it partly to see if I can manage it and can afford to take my time with it. Fortunately, the instructions I have on it are pretty decent but they are based on the input/output jack design and don't cover what I am trying to do exactly. That was why I posted the original cabling question.


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## Capt Lightning (Nov 11, 2016)

Ossian, I think I know what you're trying to achieve.   We went to the theatre yesterday to see "Sunny Afternoon", the Kinks story.  The music was fantastic and LOUD.   You needed to be at least 60 to be allowed in, but be able to behave like a 16 year old once the music started.   If you haven't seen it, I recommend it if you get the chance.


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## ossian (Nov 11, 2016)

Capt Lightning said:


> Ossian, I think I know what you're trying to achieve.   We went to the theatre yesterday to see "Sunny Afternoon", the Kinks story.  The music was fantastic and LOUD.   You needed to be at least 60 to be allowed in, but be able to behave like a 16 year old once the music started.   If you haven't seen it, I recommend it if you get the chance.


I can imagine that would be a great show and it is interesting that you mention this. Were you aware that the tone created by the kinks was very influential in the development of rock/blues music in the 60s? The story goes that Dave Davies got so frustrated with the lack of tone coming from his amp that he slashed the speaker cone in a fit of anger. When he next played through that amp, he got such a distorted tone from it that he loved it. I think that song was 'You Really Got Me'. When other guitarists heard it they were imspired to try to emulate that type of distortion. From then on, you had Townshend visiting Jim Marshall's shop to ask him to make something big and powerful that distroted well. And the rest is history......

But that sounds like a great show. Maybe I will treat myself and go see it.

Getting that type of distortion from my 20W valve amp without bursting my ear drums is what I am trying to achieve with this attenuator.


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## Capt Lightning (Nov 11, 2016)

Ossian, you have just described the opening scene of the show.   Dave slashes the speaker of a small amp to get the tone he wants.  This isn't loud enough so he also hooks up a VOX AC30, cranks everything up and launches into "You really got me".    

The show ended with a 'mini-concert' that featured some of their greatest hits.  The acoustics in the theatre were great and you could hear every note and every word of the vocals.  The standard of the musicians was incredible.  The volume could have blown your windows out.  It was bloody fantastic!!


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## ossian (Nov 12, 2016)

Sounds brilliant, Capt. You must have really enjoyed that.


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## ossian (Jan 15, 2017)

Thoughgt I would post an update on this topic.

The attenuator was built last weekend. Having received most of the components as Christmas pressies - including the soldering station! It works fine and lets me drive the amp at a volume suitable for the home. 

I bought some offcuts of studio grade 2 core 75mm audio cable for the speaker cables and they seem to work fine. All in all I am happy with the outcome. Just don't look too closely at the holes bored in the casing as they are a little squinty!


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## HazyDavey (Jan 15, 2017)

Very nice job, looks very well made. I've always been a little curious about these boxes, never used one but I think it's a great idea. :encouragement:


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