johne@ex.heurikon.com (John Eckrich) (01/24/91)
map@zeppelin.rutgers.edu (O. C.) writes: >My brother and I are building guitar amps. Any help with inexpensive >sources for step up transformers(120->350)? Use a 40V (ie. 120 -> 40) transformer, and plug it in backwards. DigiKey has the following: Part # Volts Amps $$$ ------ ----- ----- --- T107-ND 40 .110 8.25 T117-ND 40 .250 10.68 T127-ND 40 .600 14.80 -- ------------------------------------------- johne@heurikon.heurikon.com Madison, WI
dana@locus.com (Dana H. Myers) (01/24/91)
In article <Jan.23.03.46.07.1991.5100@zeppelin.rutgers.edu> map@zeppelin.rutgers.edu (O. C.) writes: > >My brother and I are building guitar amps. Any help with inexpensive >sources for step up transformers(120->350)? Step up the line voltage or impedance? One trick with guitar amps is to make the volume knobs go to 11, that way, you'll have one more to go when others have already hit 10. -- * Dana H. Myers KK6JQ | Views expressed here are * * (213) 337-5136 | mine and do not necessarily * * dana@locus.com | reflect those of my employer *
whit@milton.u.washington.edu (John Whitmore) (01/26/91)
In article <1228@heurikon.heurikon.com> johne@ex.heurikon.com (John Eckrich) writes: >map@zeppelin.rutgers.edu (O. C.) writes: > >>My brother and I are building guitar amps. Any help with inexpensive >>sources for step up transformers(120->350)? >Use a 40V (ie. 120 -> 40) transformer, and plug it in backwards. NO this is dangerous! A transformer has sufficient inductance to ensure that at its rated input voltage and frequency, current is limited so that the transformer iron does not reach its magnetization limit. Above this limiting current, the transformer is a short circuit. The 40-volt winding is lower inductance than the 120-volt winding, thus will proabbly saturate the transformer, and burn out your fuse (if you're lucky). There's lots of old vacuum tube equipment around that used moderate amounts of current at high voltage; for that matter, a microwave oven transformer goes from 120 to 1200 or so (some vacuum tubes are still around...). Look for an appropriate unit in a disused piece of equipment... somewhere. Parenthetically, 120/220V transformers for voltage conversion are relatively common; 220VAC rectifies to about 300VDC; would that do? John Whitmore
dam@cs.glasgow.ac.uk (David Morning) (01/28/91)
In article <1228@heurikon.heurikon.com> johne@ex.heurikon.com (John Eckrich) writes: ]map@zeppelin.rutgers.edu (O. C.) writes: ] ]>My brother and I are building guitar amps. Any help with inexpensive ]>sources for step up transformers(120->350)? DANGER! DANGER! DANGER! DANGER! DON"T DO THIS!!! YOU'LL END UP WITH A FIRE!! Plugging a winding designed to handle 40volts into 120volts is asking for trouble! ] ]Use a 40V (ie. 120 -> 40) transformer, and plug it in backwards. ] ]DigiKey has the following: ] ]Part # Volts Amps $$$ ]------ ----- ----- --- ]T107-ND 40 .110 8.25 ]T117-ND 40 .250 10.68 ]T127-ND 40 .600 14.80 DANGER! DANGER! DANGER! DANGER! DON"T DO THIS!!! YOU'LL END UP WITH A FIRE!! Am I imagining things or is this newsgroup becoming more dangerous? First it was "How to fry someone peeing in your window" and now this! Dave