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Connecting EQ-7545R

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I just joined the forum today and wondered if anyone could please advise me on a pickup for an acoustic guitar?

I've got a Terada classical guitar I bought in the late 1960s which I've modified slightly to get a lower action for flamenco. It's OK until I get my new flamenca blanca built (anytime in the next 10 years at the speed I get things done) but since my wife finished work she cramps my style a bit - she likes to watch TV when I want to practice or play.

I had a crazy idea the other day of buying a battered old classical guitar (cheaply, of course), filling the body with polyurethane spray foam and fitting a pickup. Then it wouldn't hardly make any noise at all, I could plug it into the sound card on the computer and listen through headphones - which would also drown the TV out . . .

I spotted an EQ-7545R pre-amp with a pickup on Amazon today (only £6 UK) and wondered if it would be suitable for my purposes. It seems to tick all the boxes - since the pickup is under the saddle it *shouldn't* rely on the vibration from the sound-board (which will be damped by the foam) and if I installed it before I sprayed the foam it would all be nice and stable in there.

Trouble is, I haven't been able to find any information about output levels and impedance or how to match it to the sound card. The blurb says it has a 2.5 mm plug - i guess that means the one from the unit to the pickup, with a standard 1/4" jack for the amplifier lead? Would it need a pre-amp to hook it up to the computer? Line in or Mic input to the computer?

I had also thought of using a 35 mm piezo transducer as a pickup, run through a J-FET buffer amp into an LM386 audio amp IC to drive headphones direct, but since the sound-board wouldn't be able to vibrate it would be difficult to know where to site the transducer where it would work.

I'm not too concerned about life-like sound reproduction - it would only be a practice guitar and only needs to be good enough for me to know I'm hitting the right notes at the right time and give my fingers some exercise. One of the Yamaha silent guitars would also be nice but they're out of my price range.

Any ideas, anyone?

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Buy Headphones for the wife ;) and plug them into the telly.......or even better throw the telly out the window :punk: ..............lol

i'm not sure about the expanding foam idea, it may not dampen the sound as much as you are hoping for - that said if you can get a cheap enough guitar and your £6 pickup, and no more than £10 for foam. it may be worth trying, to find out wether it's a good idea or not :dunno:

Paul.........

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Hi Paul,

Throwing the TV out the window sounds like a plan - very rock & roll. I'd give myself a hernia though - it's a BIG old Sony 32" CRT and weighs 150 lbs . . . !

As you say, the foam probably wouldn't make an acoustic guitar completely silent and I wouldn't expect it to. If I could just play in the next room to the TV without interfering with her listening pleasure it would be OK - and flamenco can get LOUD. I don't get on with electric guitars so don't play them but I know you can hear them *a bit* without an amp. I'd imagine a foam-filled acoustic would be a bit louder than that, but hopefully not too much.

I suppose I could try an experiment with the guitar my daughter had for school when she was about 10 - it's a plywood bodied 'classical' (loosely speaking) - think it's a Tatra Classic or a Hi-Spot. I'd have to un-string it and stuff it full of towels or something then string it up again and try it. I'd probably still get some resonance from the sound-board but it might give me an idea of the sound level. Can't annex the guitar completely - she still has ideas of playing it again *one day . . . *

I still think the idea is fundamentally sound - it just depends how it will turn out. As you say, if it's cheap enough it's worth a try. I see guitars at car boot sales for a fiver all the time (until I want one, of course . . . ;-) )

Clive

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How'do Clive,

Gumtree is another good place to find used guitars locally, although it's a bit like the carbooty, nothing but bargains when strapped for cash, and nothing suitable when actually looking to buy....

it's possible to buy a new cheap student guitar with nylon strings for @ £30, but adding in the pickup and foam - £50 - a lot of money to gamble

as for the pickup - i made a pickup (for an acoustic guitar i built), from an old smoke alarm buzzer, it's passive and obviously has no pre-amp or EQ etc... but i think it sounds great, and can be placed anywhere on the guitar body....

i think it was Karcey who posted a similar home made pickup made from a buzzer/sounder/beeper/whatever - which gave me the idea to use the old smoke alarm........i'll find the post and link it here

Paul.....

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They're looking a bit expensive on Gumtree and Preloved at the moment; car boot is usually best - the sellers always seem grateful to get rid of them when someone buys one . . . Mind, I've seen some terrible things done to guitars at car boot sales too - left out in the rain, stood on wet grass, things stacked on top of them . . .

Thanks for the pickup link. This is what I was originally thinking about with a piezo transducer; they'll work as a sounder or a mic As luck would have it I bought 5 of them for about £2 on eBay for a different project. Only thing that worries me is where to put it on an acoustically dead guitar. Perhaps the author's idea of putting it under the bridge would be OK - but if it isn't, there's no way back once the foam is in . . . If I used the DIY pickup idea I could go down the dedicated headphone amp route - I've got everything I need for that and it would cut out the need for the computer. I've got one, obviously, but I don't necessarily want to be tethered to it. I could get the amp into the ubiquitous Altoids tin - apart from the PP3 battery . . .

I read somewhere that the EQ-7545's pickup has six separate sensors tuned to each string, so its frequency response will probably be better than a single pickup.

Wish I knew. Let's hope it's fine on Sunday for the car boot sale so I can get something moving ;-)

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here's a link to the guitar i made, it has 2 pickups - a speaker, reverse wired, that is inside where a soundhole would be, doesn't sound great tho...

i mounted the other pickup on the front of the guitar, i had a wee play around to see where sounded best, also the bracket i made allows for some adjustment in the position :)

http://www.guitarforbeginners.com/forum/index.php?/topic/27538-home-made-guitar/

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Nice job on the guitar build - very inventive. I guess it wasn't too expensive to build so if it didn't work out all you would have lost was the time it took?

I'm harbouring ambitions of a bit of luthiery myself - I've spent 3 years collecting all the woods for a flamenca blanca. I've got them as and when they've become available - got some nice Englemann spruce for the soundboard on eBay one Christmas day while the rest of the civilised world was listening to the Queen's speech so mine was the only bid; I imported some 100-year-old cypress from Canada for the back and ribs - the shippping cost twice as much as the materials so I bought two sets for the same shipping (and it was still cheap. . . ) I got some brilliant Spanish cedar for the neck in a clearance sale . . . the list goes on and I'm in for a small fortune at the moment . . .

And then you come along and nail some joists together and cover them in shuttering ply and it sounds brilliant . . . :brickwall:

Seriously, respect to you. If my efforts eventually sound half as good as yours I'll be a happy bunny!

Actually, I was having kittens over cutting into the wood I've bought so I took the advice in one of the books I've got on guitar-building and bought a complete set of second quality wood to try the techniques on first. I got some Western red cedar for the soundboard and maple for the back and ribs, and again Spanish cedar for the neck. I'll build that one first and learn from my mistakes - and I'm sure there will be more than a few!! I've worked with my hands for a living but only in metal - and mistakes there are relatively easy to rectify! I've never done any *real* woodwork but there aren't any seriously complicated joints involved in a classical-type guitar - not even a dovetail at the neck joint since the traditional joint is a Spanish heel. I'm setting up a wood workshop at the moment and making tools so I can't even start building yet (got a fully-equipped engineering workshop but I don't want sawdust all over my machine tools or oil and grease on expensive timber . . .)

Been doing some research today - went to a guitar shop 10 miles away to ask about the EQ-7545 but the guy had never heard of it, doesn't have one and wasn't interested in getting one for me. When I mentioned that I wanted to hook a pickup into a sound card he said you could get the kit to do it, but he doesn't know which one would do it, doesn't have anything like it in the shop and wasn't interested in getting one for me . . . And he was the owner :-(

I made my excuses and left.

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How'do Clive,

i look forward to seeing the results of your project :) in time, i have patience ;)

sounds like you have some nice materials, and aye, definitely worth getting more confidence with your woodworking skills before committing expensive materials to tool work.......

i'd like to purchase some nice timbers for a guitar project someday, my homemade guitars are more recycling projects, i haven't spent any money on them

i work on my bedroom floor, with just a few basic tools too, so i don't really have any expectations when i start, but i enjoy the process and the challenge of the limitations :)

my advice for woodworking (and everything else really) - is to be confident, and use the force.....if we focus on what can go wrong, it will ;)

i've had similar experiences with Guitar stores (and other shops) - staff being reluctant to help or offer advice to some of my questions/inquiries - especially if there's not an immediate sale in it for them - but they'll miss out on any future purchases i may make - bad attitude = 1 less future customer

Paul.......

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I look forward to seeing the results of my project - just not anytime soon, sadly. Got too much else going on and I can't make it a priority at the moment.

I've drawn inspiration from a series of three 20 minute YouTube videos called 'Birth of a Guitar' by the Wood Whisperer. I tried to post links but I haven't quite got the hang of this site yet - it keeps telling me I've exceeded the amount of media files I can post . . . If you're interested in seeing an hour's worth of a classical guitar build from start to finish it's worth a watch . . . One good thing is that he shows the 'gotchas' which I now know to avoid.

The build is a little power-tool heavy for my taste, but I could easily adapt that to hand tools. I don't have a thickness planer but I do have a Safe-t-Planer (again, you can find it on YouTube) which works on a drill press, and I can easily and cheaply build a thickness sander. I need some good gouges for carving the Spanish heel, but I can make them - I made new newell posts for my stairs years ago so I built a crude woodturning lathe and made a huge skew chisel out of an old cast steel file, so the gouges should present no problem.

I have a pretty good collection of books on classical guitar building going back to the 1950s which contain lots of conflicting information so I'm taking one bit from one book, one from another and so on. The best of the books I have, IMO, is the 'Guitar Maker's Workshop' by Rik Middleton, so I'll mostly be following his methods.

I'm a big believer in The Force too - but those light sabres are a bit full-on . . .

I'll see what the weekend car boot sales bring (if the weather is OK) and if anything turns up cheap enough I'll have a go. Otherwise I may just implement Plan 'B' which i just formulated. It involves a solid bodied electric classical guitar and a cheapo pickup and equaliser. Or a plank straight down the middle to represent head, neck and somewhere to hang a bridge with vestigial 'wings' to give it the classical shape and save weight. Or did Yamaha think of that first with their Silent Guitar . . . ? ;)

Clive

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