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Messages - dg

#1
Hi Guys I now have a decent soldering iron and a bucket of enthusiasm

I buy pre amps to increase the output of the under saddle transducer pickups I fit to the acoustic guitars I make (hobby builder) can I make a simple pre amp to just boost the signal ,no eq volume ect  must be 9v battery powered that I can mount  inside the guitar that's a simple schematic that even a novice can understand
Thanks
David
#2
Hi Juan thankyou so much for all you help, the amp may have languished in the loft forever but nows shes up and running
I will make a soundfile and post
thanks again
David
Ps onto my next project I make acoustic guitars and buy in preamps now to make my own they have a kit as a starter in maplin !!!!
#3
Hi Juan I couldn't get any specific earth wire so an electrician at the shop said to strip the 3 core from standard mains cable and use that(is that ok?) I bought a neon screwdriver and have tested the top panel ,I bought a new soldering iron and soldered everything I will make some wood blocks to hold the wire and bridge steady .it all seems to working great I have enclosed a couple of pictures the solderings getting better , no dry joints just a little to much solder  tell me what you think
Many thanks for your help
Garry
#4
Hi Juan many thanks for the pic and help just a  couple of questions
QuoteYou must also use some hot glue to attach that floating rectifier to the silver  filter capacitor for the same reason
PICTURE (1)filter capacitor has a bolt on bracket i just removed it for the pictures

PICTURE(2) there are two identical black wires going to the old two prong mains plug socket from the Transformer but it can be  connected  to the amp mains lead in either way(up or down) this is the bit i,m worried about!!!!
how would I know which one goes to the live and which to the neutral  on the new switch? is my friends suggestion correct?
many thanks Juan i will add an mp3 and more pictures when shes up and running
david



#5
Hi juan I have mounted the switch /mains socket on a hard plasitc plate ,routed a larger hole (to cover the old one) but conected the Original mains one back as it was and its inside the amp (see pic) When I know the correct way to wire the new mains switch should I use crimped connectors or solder them?
many thanks
david

I am very excited and really looking forward to using the amp safely
 
#6
Hi Juan (starting to get the hang of this posting LOL)
sorry should have read

(1) there are two identical black wires going to the old two prong mains plug socket but it can be  connected  with the amp mains lead in either direction (up or down)
how would I know which one goes to the live and which to the neutral  on the new switch?

(2)you metioned grounding (pic two) is the new switches earth going to the twisted arrowed bolt?


(3) bolt at the bottom of the amp should i put it all  inside?


many thanks
david
#7
Hi Juan thought I would add a picture of the large silver thing that the bridge rectifier it attached , also there are two identical black wires going to the old two prong plug socket you can plug

the mains lead  can be connected  in either direction (up or down)
how would I know which one goes to the live and which to the neutral ? my friend told me that the correct way to put the mains plug in and to connect a guitar lead to just the amp and hang the other ends jack plug in front of the amps speaker and  then disconnect the mains plug reverse it and the position with the least hum coming from the amp was right?

he said he did this many years ago with his two prong amp lead ,but was not sure if its correct and he has less knowledge of electronics than me (if that's possible LOL)
many thanks
david 

PS the silver thing and the transformer? Are mounted on the bottom of the amp with bolts that can be touched from the outside should I re mount them on a block of ply inside?
Many thanks
And thanks for the link I see what you mean about using  lots batteries LOL



#8
 Hi Juan I have got the parts ,HeHe and I found a piece of hard 3mm black plastic I could use to mount the switch or I have some aluminum tread plate?

Are the positions in relation the the + the same on all Bridge Rectifiers?


+   s2
s1   -


if so

(1)The + is connected to the three center prongs then out via the white with a stripe to the circuit board

(2)to the left of the + (s1) is orange (and goes to the transformer?)

(3)to the right (s2) green goes to the top panel switch

(4) The - goes to the outer prong on the aluminum tubes case then via a yellow wire to the circuit board

(5) picture of the back of the switch
thanks
garry
#9
Hi Brymus ,Juan really seem to know his stuff and I'm very keen to get the amp safe and working as it should, and he is being most helpful and informative
I'm keeping a little log that I will post with pictures on the forum when its finished and will update as I work on it
I am absolutely staggered at the sound quality, my friend played through it and is now looking for one (This man with a collection of  vintage valve amps!!!!!!) he said it was the most percussively responsive transistor amp he had ever played (he's also a staggeringly good guitarist)

I have had a looked inside and can't find any topless woman LOL
Thanks
david
#10
Hi Juan its option 1
Quoteplug it straight on 240V, you turn it on and play
yes I just Plug it in works great, takes a while to power down ,
surely it wouldn't work if it had the US 120v transformer in it ?

My folks are originally from Garrynagree "we do get about us Irish LOL" My mother has never fully settled here 40 years on ,she still occasional mentions the "hard water, no decent bread ,different sunlight, the cold ,the heat, the cats appear to be different here as well LOL and how washing always dried quicker at home ,she cant explain the physics of it, but I will keep asking LOL

Have a good day
thanks
david     
#11
Hi Juan the link is http://www.maplin.co.uk/Module.aspx?ModuleNo=19088
Quote2) If your transformer is 110/120V and you use your amplifier with an external 240>120V transformer, it might be interesting to buy an equivalent new 240V primary transformer and avoid carryinf useless weight.
its 240v in the UK i dont use an external transformer ,i thought it would blow up if you plugged a 110v appliance into a 240v socket?
it seems to work? how can i tell if its a 110v or 240v?
QuoteUK has a mighty fine tradition of electronics builders.
yes I think we do but because its so cold all the time there is  a general apathy towards everything LOL
Quotethose "new, promising" amplifiers called Marshall
I have had two Marshalls loved both but my mesa boogie was the most wonderful thing, heavy as hell but a sound to die for .sadly divorce left me with no Gretsch or mesa (liquidation of assets) but I got the kids so it was excellent exchange.
My son has gone over to the dark side after two years of guitar lessons he has just taken up the bass !!!!!!!!I bought him a mini
one " Smoke on the Water Bass line "great the first time by the 200th Ahhhhhhhhhhhhhhhhhh
Thanks
david
 
#12
HI juan just a quick question so i can get all the bits at the same time
QuoteYou must also change the puny round 1A bridge rectifier for a rectangular, flat, 6Amp x 200V (or better) bridge rectifier.
the bridge rectifier, better in what way more amps?more volts? are there other bridge rectifier options ,i will get the one you think best.
and is there anything else i will need , specific wire or any other components ect i can buy at the same time, i have plenty of mdf but also some 6mm birch ply that might be better, stronger? and a decent soldering gun and a new found enthusiasm
many thanks and i think the panel must be the original one with the writing on?

david
ps hi joecool85 i,ve been called worse LOL
#13
Hi J M Fahey many thanks I am gouing to try and do it my self then have it properly seviced,  I don't know anyone with any electrical experience most are just like me plug in and play, but I intend to change that .I am in the UK (so its 240V) in a rather remote part of Norfolk but I am careful used to doing things properly and an eager to learn I will get the switch and is this square one in picture  correct
Quote1A bridge rectifier for a rectangular, flat, 6Amp x 200V (or better) bridge rectifier
ther seems to be a lot of codes shall i just ask for a 6amp x200v?
many thanks
david
very excited
#14
Sorry Mr J m fahey I read my last post and I seen to have given up before I have even started,I welcome your help and any assistance you can give will be most appreciated ,I joined the forum to learn about amps electronics ,I wire up all my guitars transducers preamps ect and have built preamps from kits but have never understood how or why they work ,and perhaps the little freedom amp should be my first proper project ,I have been reading posts to try to understand the basic principals as it has always fascinated me
QuoteSo, first task is to cut a rectangular opening on the side (say, 2.5"x4"), where now the power socket rests, and mount there a somewhat larger piece of 1/8" Masonite or MDF , with 3 holes for: power cable, power switch and fuse holder (2A for 119V ; 1A for 220V)
I'll post a drawing for you to play it safe.
Posting a drawing would be most appreciated  can i send you some small picture to se if the are the right components
there is a switch on maplin that seems to combine all three would this be suitable

many thanks

dg

#15
Hi j m fahey many thanks  I think that's all a bit technical for me to do ,you lost me after drill three holes LOL but thank you for the help ,it really is a great sounding little amp  but I prefer my limbs intact and when amateurish and fire are use together I'm usually looking for the nearest exit LOL It seems rather difficult for a novice to fix
Thanks
dg