The Steel Guitar Forum

Some of the other mics suggested in this thread have been real good altenatives to the SM-57. The Beta 57 is also a really good mic and comes with the tighter hyper-cardiod pickup pattern. My partial reason for recommending the Co4 is that a Beta 57 would set most folks back about $150, whereas a Co...

Regarding the mic to speaker compatibility, I guess I have not been playing matchmaker too carefully. I've used the Co4 on a variety of amps, including a Webb amp on a weekly basis, a Line 6 for fiddle and tele, and a Fender Tonemaster amp for a tele; also every weekend. I've also used the Co4 on se...

As a novice pedal steel player and a sound engineer for a band with a pedal steel player, I want to shamelessly recommend a microphone for pedal steel amp micing. I used to go with the crowd and use a Shure SM-57. But then I tried the EV Colbalt 4 (Co4) and the fidelity blew me away. Much like going...

The 2N2222 and the 2N290whatever are pretty much generic 100 beta NPN and PNP silicon transistors found everywhere. Regarding bootstrap diodes, very few pedals and other electronics use them. Why? Because most designers did not know enough to invision a possible failure mode the way Keith and Hartle...

Hilton's pedal too expensive? Actually, I thought Keith's pedal is too cheap price-wise compared to what guitar players pay for custom/boutique pedals. As an Electrical Engineer, I know the kinds of circuits Keith uses, and they are strictly the stuff you would find typically in recording studio con...

Hi Keith,

I do hope you are suceeding in de-rippling your supply. Since you mention that you are using thick traces, including the ground reference point, most of your troubles will be small. Good Luck!

Consider doing like I do and subscribe to the synth-diy and analog heaven list servers. Yeah, you get daily about a hundred e-mails, but you can browse the titles and delete the chaff. Most of my cherished d-i-y synth books are long out of print. All this technology still applies to instrument effec...

Regarding the balanced lines game, a couple of thoughts: One is that good audio transformers can have excellent performance if designed for the appropriate circuits. One has to keep an eye on signal levels and transformer materials and winding practices. The best transformers for pro-audio can be fo...

To add to Jack's comments, 14 gauge or better wire is good for your higher powered amplifier. Good terminations are equally important too. If you use phone plugs, you may have to back down to 16 gauge to get the wire to fit in the barrels of the connectors. I recommend type "SJ" rubber jac...

Let me attack the problem from the reason why some are forced to lift grounds; hum. If the first grounded AC powered circuit (usually the guitar amp or rack preamp)had the intact ground, then suceeding grounded circuits like second guitar amps or additional power amps would cause the ground loop hum...

In your business Keith, using low ESR electrolytic caps everywhere is just another statement toward superior quality. I believe performance over price is your current philosophy. I like the Panasonic HF series of low ESR caps (dark blue covering) for my audio prototypes. The better nichicons are goo...

Low Effective Series Resistance (ESR) and low ESL capacitors vary from general purpose capacitors in the amount of construction. For example, a general purpose electrolytic cap has only two foil-to-terminal tabs; one for the aluminum foil anode (+), the other for the aluminum foil cathode (-). Where...

Parts Express has 200 watt, 4 0hm audio dummy loads that may solve your problem. I've bought four of them last year to create a 4 ohm, 800 watt load for testing PA amplifiers. They cost $33.50 each and are rather large (about 6" x 3" x 1") sandcast resistors with aluminum extrusion en...

Most (not all) stomp boxes have AC adapter jacks that will either switch out the battery or diode protect the battery clip by supplying a higher dc voltage than a fully charged battery. Regarding the tube screamer voltage thought; the magic in tube screamers is make the internal op-amp struggle with...

Any snake should have an all-XLR fan-out at the mixer end. The exception is to substitute TRS (tip-ring-sleeve) phone plugs on the mixer outputs. If you drive a long snake, always used balanced connections. As long as the snake mixer fan-out had XLR males for mics and XLR females for power amp retur...

The 2N3773 is 16 amp (Ic), 140 (Vbe) NPN power transistor commonly used in 1970's through 1980's high power audio amps. I know Peavey and Crown International used alot of these types then. Motorola still makes the 2N3773 as a standard part. They are overkill for the RCA 40636 application (15A, 80V),...

Mouser Electronics (mouser.com) sells the 2N5882 for $2.02 and the 2N5878 for $1.42. Both are nearly equal for the audio power application, but you may want to choose the 2N5882 part only because Motorola promises to continue to build replacements for awhile longer. Mouser does not sell the Motorola...

Your 40636 part is TO-3 can (flanged) NPN Power Transistor with a 15 ampere collector current and Vceo of 80 volts or more. The direct replacement is a Motorola 2N5878, but a Motorola 2N5882 is a present day recommended part for best availbility and lowest cost (probably a few bucks each at retail)....

Those old 40XXX parts from RCA will likely be cross-referenced to NTE equivalent or some similar semiconductor line. After having blindly following the cross-reference books for years, I took advantage of my EE education and do my own matching based on the old specs and look for a "present day&...

Question: For those of you who get the luxury of getting their amps mic'ed up, what mic types do you use (or provided) and what part of the loudspeaker cone is the mic focused at? I am guessing that most players get a Shure SM-57 that is either draped over the amp (looped through the handle) or a di...

Depending on who did the LED and switch modification, the extra 2 to 20mA current draw could quickly chew up that 120mA-hour battery life that Keith states. If you gotta have a battery powered "on" light, have someone buy the ultra-efficient and bright red LEDs from Hewlett-Packard. They g...

Most speakers or speaker cabinets have a continuous (RMS) rating that for musical instrument purposes is good enough. PA speaker cabinets have a little different ratings game. Generally there is a program power rating (about 2x RMS rating), and a peak power rating (about 4x rating). Then for maximum...

I can't say I've ever seen it on solid state amps. Usually, my first line of troubleshooting is aimed at battery powered stuff. They have the nasty habit of fade out as the battery gets to end of life.

Mark,

I will not ring the bell for or against Keith's opto-pedal until I try one, but the emperical demo results are true just based on basic electronics theory. We (some of us) use buffer stages to create high impedances for the pickup tonal preservation and also to be able to drive the cable capacitance...

The RF problem generally can be just limited, not eliminated. Good shield cabling, circuits with .01uf to .1uf supply bypass capacitor (ceramics), and good quality metal chassis with few cracks or open seams are the best preventive measures. Fortunately RF signals attenuate rapidly as the distance f...