Replies to This Discussion

Permalink Reply by Don Thompson on January 23, 2011 at 9:09am

I would have to say the output impedence of your guitar is a very poor match to the tape player without an adapter. If perhaps you would post a link to said sites and we could look at them, cause otherwise we are just guessing to what wires go to what. Some of the old tape players had a seperate preamp for plugging into.

Don

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Permalink Reply by Michael Gajeski on January 23, 2011 at 10:12pm

Ive done this, but there were only two wires. they were attached to the back of the part that reads the magnetic tape. I attached them to a jack and was in business. The volume on it isn't great, and it sounds like I have a crazy overdrive effect on when i use it, but it works.

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Permalink Reply by anotola humbuckker on January 24, 2011 at 2:49am

well, the site was an explination for a boombox turned into an amplifier for an ipod, which i guess maybe has a better output independance, and sadly enough mine is not verry old so i guess doesn't have a seperate pre amp (although i would not know what this looks like ...

i can't find back the mysterious place where i read this guide

 is there any diy solution to an adaptor?

thanks for the help!

Don Thompson said:

I would have to say the output impedence of your guitar is a very poor match to the tape player without an adapter. If perhaps you would post a link to said sites and we could look at them, cause otherwise we are just guessing to what wires go to what. Some of the old tape players had a seperate preamp for plugging into.

Don

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Permalink Reply by Brendan deVallance on January 24, 2011 at 3:52am

My first thought was that the Mag tape head wires would not be the place to jack into.I'd follow those leeds to the amplifying part. of the boom box. does the unit have an aux in jack? that is the perfect place to try. Or any type of Line in.

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Permalink Reply by petey twofinger on January 24, 2011 at 10:10am

tried this on a walkman type tape unit when i was a kid . 3 wires on the head , you have to cut into both hot sides to get r and l channels . no matter what you did it was distorted to the point on "non-usability" .  good luck though , let me know if you have success .

 

i have used kiddie tape decks , but you cut into the mic in . if you find an off brand chinese one (NOT FISHER PRICE) they scream . some of em have a limiter switch thats hidden under the battery compartment , that can double as a boost , or od . believe it or not the one that i modded sounds fantastic . and it was 1.25 at salvation army .

 

http://img267.imageshack.us/img267/2500/sdc15241.jpg

 

another "cheapo " aproach , if yer lucky is karoke machines . IF you can find em free or super cheap .

 

 http://img171.imageshack.us/img171/1152/001oz.jpg

 

made this one last night , modded the echo too . i had this tiny karoke machine from the 80's , 3 watts , echo , and it SCREAMED ! super feedback , also great guitar tone . the circuit bored was TINY as well . i fried the chip while modding it , an aligator clip slid under the board while i was reaching for a tool on the table . i am soo beating myself up over that one !

 

i guess if i had the cash to buy kits or modules i would but , this way is much more rewarding for me anyway .

 

rats off to ya for tryin man , thats awesome .

 

 

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Permalink Reply by anotola humbuckker on January 24, 2011 at 10:38am

wow, your amps look nice, not anything like the tore-up boombox i have in front of me.. ha.

ah well,  maybe  i need some better materials, i like lurking around second hand shops, so this is not a problem.

as for what brendon sais, how do i recognise the amlifying part, i mean the tape head cables just go back to the cirquit board, and that is chinese to me, all the little resistences and so forth, i have no idea what this does.....

tommorow i might just try connecting it the jack wires to different wires sticking out the cirquit board, see what happens.....

petey twofinger said:

tried this on a walkman type tape unit when i was a kid . 3 wires on the head , you have to cut into both hot sides to get r and l channels . no matter what you did it was distorted to the point on "non-usability" .  good luck though , let me know if you have success .

 

i have used kiddie tape decks , but you cut into the mic in . if you find an off brand chinese one (NOT FISHER PRICE) they scream . some of em have a limiter switch thats hidden under the battery compartment , that can double as a boost , or od . believe it or not the one that i modded sounds fantastic . and it was 1.25 at salvation army .

 

http://img267.imageshack.us/img267/2500/sdc15241.jpg

 

another "cheapo " aproach , if yer lucky is karoke machines . IF you can find em free or super cheap .

 

 http://img171.imageshack.us/img171/1152/001oz.jpg

 

made this one last night , modded the echo too . i had this tiny karoke machine from the 80's , 3 watts , echo , and it SCREAMED ! super feedback , also great guitar tone . the circuit bored was TINY as well . i fried the chip while modding it , an aligator clip slid under the board while i was reaching for a tool on the table . i am soo beating myself up over that one !

 

i guess if i had the cash to buy kits or modules i would but , this way is much more rewarding for me anyway .

 

rats off to ya for tryin man , thats awesome .

 

 

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Permalink Reply by petey twofinger on January 24, 2011 at 11:02am

well in most cases the amp component would have a heat sink , or something to disapate the heat . another way would be to trace back from the volume pot .

 

thanks for the kind words .i have found that when you do locate the amp sometimes it is on its own seperate board . the radio will have its own board as well . i have been able to cut all the wires off the amp board that go to the stuff i am not going to use , and have the amp still function . which is then just a matter of mounting the board in a chassis . that metal amp was a juke box powers upply chassis , i garbage picked from "the arcade place" . it has a different tone cause its metal too !

 

honestly i think you may find it a bit challenging to match the impedance , you could poke around with your finger and if you get a quieter buzz than you do on the head lead , cut in an input and try that , but . or you could buffer your guitar input to match , you would need to lower the input to it a bit , i believe a transformer would be involved , guitar to primary , tape lead to secondary . some sort of audio step down transformer , if you could find one . do you have a vom or an ohm meter ?

 

or the simplest approach would be just putting a resistor in the path . google 10k resistor , then do an image search , write down the color bands . then get some old junk circuits and find some resistors in the 1 to 50 k area , remove them , and see what happends when you cut em in . keep me posted , i love it if you could nail this one down . i'm a little soldered out right now , although i have to replace a pot in last nights amp , it broke when i tried to force a knob on it from the glue from the old knob ! DOH !

 

 

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Permalink Reply by Vagabanjo on January 24, 2011 at 11:29am

I build a small amp from a kids guitar that had a speaker built in, I put a differnet spesker in, in fact one 8ohm on the fromand 2 8ohm on the back in series, with a switch to go from front to back, the guitar is better on the one and the ipod better on the two!. Great sound an even better on headphones. I then tried a sub woofer,but ended up great with anipod and horrible buzz no sound with a guitar. I will try aneffects pedal between guitar and sub amp to see if that converts the anologue to digital resulting in sound!

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• AllAmps.JPG, 67 KB

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Permalink Reply by anotola humbuckker on January 24, 2011 at 11:37am

honestly i think you may find it a bit challenging to match the impedance , you could poke around with your finger and if you get a quieter buzz than you do on the head lead , cut in an input and try that , but . or you could buffer your guitar input to match , you would need to lower the input to it a bit , i believe a transformer would be involved , guitar to primary , tape lead to secondary . some sort of audio step down transformer , if you could find one . do you have a vom or an ohm meter ?

 

well, that sounds mighty complicated, but i do have an ohm meter/multimeter, which some guy said i needed when i wanted to make my own pickups (i used it and got a reading, but didn't understand what it meant, so i just made the bobbin of copper as big as i thought it should be, works fine by the way).

what you said before about attaching the jack to the two hot wires actually worked!... a bit

there's a huge hummmmmmm going on but i hear the strings, distorted but with a cool reverb effect!

the humm is muffeld a bit when you touch the black cord from the tape head, leading me to believe that the black and yellow may be grounds, i might try to solder them back to the tape head tommorow, maybe it will help a bit right?

 

but if i understand right (this is my first endevour in amplifying so pardon the ignorance) my guitar ohm reading and the tape head ohm reading are probably radically different leading to a buzzing noise?

 

so where exactly do i poke around with my finger, where ever there are wires?

kind of goes against what your parents tell  you when youre a kid, but what the heck.

putting in a resistor would be quite a challenge, but anyway i'm going to keep trying!

thanks for all the help so far!

 

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Permalink Reply by petey twofinger on January 25, 2011 at 9:05am

putting a resistor in-line a challenge ?

 

for the question you asked , how I DO IT , is lick the finger , touch the red wire , does it hum ? if yes then grab the red wire again , get it buzzing good . now with your other hand grab the black wire while it is buzzing / you are holding the red . did it stop buzzing , or the buzz was reduced quite a bit ? then the black is a ground . now determine if the yellow wire indeed is a ground as well , and if the white is an input like the red . once you know what they all are , connect them to the jack , use all the grounds to the ring side , and all the inputs (or positives) to the tip . or just go with one input , run the amp off one channel , or you could bridge em . shit i  better stop .  short version , yellow and black to ground , white and red to pos (if you are right about what they are and it sounds like you are) .

 

well anyway ,yes the guitar ohms and the tape head ohms are different . ohms are resistance . and yes soldering properly will eliminate buzz quite often but , if you find that when you it all hooked up nice , and you cant get a clean tone , its a ll fuzzy or distorted , thats when you would try cutting in a resistor .

 

last night i opened up a pc speaker with an amp in it . when you connect a guitar to it you can hear it , but its very quiet . i used the volt meter to determine the amp was running off of 11 volts AC . by testing the wires that go from the transformer to the circuit board . 11 volts ac , nothing to make my hair stand on end . i looked at the board , there were about 8 resistors . i figured one that was very near the only chip on the board was prolly setting the input gain for the amp (impedance) . at this stage i sometimes opt to use a probe instead of a wet finger . i have one that is 2 nails , with a wire between em , another that is 2 nails with wire , and a 1k resistor in the middle .  i used the resistor probe and started bypassing the resistors by touching the probes to both sides of a resistor , one at a time . sure enough i found the input gain resistor , and when by passed , the amps impedance matched the guitars a lot better than with the resistor . it became nice and loud , but not distorted .  so i will remember that if i want to convert something into a "guitar amp" and its really quiet with guitar , but cranks with a line level signal , you just bypass the input resistor .

 

your case is the other way around , the signal generated off the tape head is LESS than guitar . so when its hooked up , the guitar is gonna be too loud and have very nasty distortion . you could try and put a resistor in to match it up , but getting the right one may be hit or miss .

 

you could put it on the hot side of the guitar to tape head lead connection , but personally i would try and find the input gain resistor . get an old radio that has a headphone jack , run a cable out of that to the tape lead , adjust the volume so its kinda quiet . get 2 nails , some wire , make a probe and then tape up the nails (except the tips) , look for a chip on the board that has a heat sink . start bypassing the resistors that are around it . if you dont know where the amp is on the board , just do each resistor , one by one . if it sparks , take it off , it it pops , take it off , eventually you should hit a resistor that when you touch both its leads (this is from the top)  the volume will jump up.

 

you found the input gain resistor . use the ohm meter , to determine the resistor value .  remove the resistor , now you could put in a larger value resistor or a pot so it is adjustable . then again you may get lucky , the distortion may actually be desirable , i know when i did it , it was just waay to hot , unusable .

 

i started doing this stuff when i was a kid , i ENJOY doing this quite a bit . i wish i knew more though , so i look at problems with delight , cause i almost always figure em out . the  most important thing is that you NEVER EVER use plumbers flux .

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Permalink Reply by anotola humbuckker on January 25, 2011 at 11:29pm

Man, thanks a lot for the lesson in amateur electronics!

i have to read your posts 3 times, but afterwards i feel i understand something!

and i like the nails and wire tool,

anyway back to work, and back to experimenting tonight!

petey twofinger said:

putting a resistor in-line a challenge ?

 

for the question you asked , how I DO IT , is lick the finger , touch the red wire , does it hum ? if yes then grab the red wire again , get it buzzing good . now with your other hand grab the black wire while it is buzzing / you are holding the red . did it stop buzzing , or the buzz was reduced quite a bit ? then the black is a ground . now determine if the yellow wire indeed is a ground as well , and if the white is an input like the red . once you know what they all are , connect them to the jack , use all the grounds to the ring side , and all the inputs (or positives) to the tip . or just go with one input , run the amp off one channel , or you could bridge em . shit i  better stop .  short version , yellow and black to ground , white and red to pos (if you are right about what they are and it sounds like you are) .

 

well anyway ,yes the guitar ohms and the tape head ohms are different . ohms are resistance . and yes soldering properly will eliminate buzz quite often but , if you find that when you it all hooked up nice , and you cant get a clean tone , its a ll fuzzy or distorted , thats when you would try cutting in a resistor .

 

last night i opened up a pc speaker with an amp in it . when you connect a guitar to it you can hear it , but its very quiet . i used the volt meter to determine the amp was running off of 11 volts AC . by testing the wires that go from the transformer to the circuit board . 11 volts ac , nothing to make my hair stand on end . i looked at the board , there were about 8 resistors . i figured one that was very near the only chip on the board was prolly setting the input gain for the amp (impedance) . at this stage i sometimes opt to use a probe instead of a wet finger . i have one that is 2 nails , with a wire between em , another that is 2 nails with wire , and a 1k resistor in the middle .  i used the resistor probe and started bypassing the resistors by touching the probes to both sides of a resistor , one at a time . sure enough i found the input gain resistor , and when by passed , the amps impedance matched the guitars a lot better than with the resistor . it became nice and loud , but not distorted .  so i will remember that if i want to convert something into a "guitar amp" and its really quiet with guitar , but cranks with a line level signal , you just bypass the input resistor .

 

your case is the other way around , the signal generated off the tape head is LESS than guitar . so when its hooked up , the guitar is gonna be too loud and have very nasty distortion . you could try and put a resistor in to match it up , but getting the right one may be hit or miss .

 

you could put it on the hot side of the guitar to tape head lead connection , but personally i would try and find the input gain resistor . get an old radio that has a headphone jack , run a cable out of that to the tape lead , adjust the volume so its kinda quiet . get 2 nails , some wire , make a probe and then tape up the nails (except the tips) , look for a chip on the board that has a heat sink . start bypassing the resistors that are around it . if you dont know where the amp is on the board , just do each resistor , one by one . if it sparks , take it off , it it pops , take it off , eventually you should hit a resistor that when you touch both its leads (this is from the top)  the volume will jump up.

 

you found the input gain resistor . use the ohm meter , to determine the resistor value .  remove the resistor , now you could put in a larger value resistor or a pot so it is adjustable . then again you may get lucky , the distortion may actually be desirable , i know when i did it , it was just waay to hot , unusable .

 

i started doing this stuff when i was a kid , i ENJOY doing this quite a bit . i wish i knew more though , so i look at problems with delight , cause i almost always figure em out . the  most important thing is that you NEVER EVER use plumbers flux .

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Permalink Reply by anotola humbuckker on February 1, 2011 at 12:35am

Sucsess!

well, sort off, attaching the yellow to the white wire took away all of the buzz, so now it's only sounding distorted, also, at first it wasn't verry loud, but after a bit off freestyle poking, i found out that if one attached two nodescript items on the cirquit board the volume boost way way up.

so thanks for the help!

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