I have used op amps into headphones with some success.
The foot pedal will probably have op amps driving the output.
I used a pair of op amps on a mobile disco for monitoring each record deck channel into headphones. They weren't mind blowing loud but I could hear each channel at a reasonable level.
You could try plugging high impedance headphones in to your pedal.
The foot pedal will probably have op amps driving the output.
I used a pair of op amps on a mobile disco for monitoring each record deck channel into headphones. They weren't mind blowing loud but I could hear each channel at a reasonable level.
You could try plugging high impedance headphones in to your pedal.
The 386 is a good plan, but sure you CAN build a power amp with separate parts, just not with little JFETs. The preamp amplifies the signal voltage, but to move a speaker, you need some power, so a power amp also is a current amplifier.
It can, but what would be the point?.
Before IC's all power amps used discrete components, but you were wanting a simple solution - and an LM386 is ideal for what you want.
You've not looked at his circuit - a simple JFET preamp with a high impedance passive low-pass filter at the output (no opamps).
Opamps are commonly used to feed headphones, in fact I've recently designed just such a circuit for a friend - but it doesn't mean you can just stick headphones on a line output, just because it has an opamp inside.
Okay, it is clearer now. If I compare what I am trying to accomplish to one of my guitar amps. The preamp circuit will "sort of" duplicate the 12ax7s in my amp and the LM386 will duplicate the 6l6gcs in my amp. The JFETs can't duplicate the 6l6gcs.
And again, thank you for taking time to reply. Your knowledge and patience has been very helpful as I go through this learning process. I am spending hours on the internet trying to understand how to build these small circuits as I find it interesting and fun and it is very helpful to have someone to offer guidance that has experience which will help me avoid mistakes.
Ok, since you insist, help yourself:
and if you are Macho enough, here's the discrete version of "just some diodes, transistors, and resistors in one package" :
An externally hosted image should be here but it was not working when we last tested it.
and if you are Macho enough, here's the discrete version of "just some diodes, transistors, and resistors in one package" :
Thank you for taking time to post all of this information. I will not let it go to waste.
Keep in mind, that a guitar amp and speaker are a part of the whole instrument, they produce a frequency response contour and distortion products specifically for guitar. A guitar played through HiFi stereo amp and speakers will sound flat and uninspiring. Building your own musical instrument amp and speakers usually ends in disappointment. As I said before, you should look for a good deal on the real thing.
Mike
Mike
That's only if the player is flat and uninspiring, it sounds just as good as anything else with a decent player (if not better). I've known a number of guitarists who used HiFi amps in preference to guitar ones because of their better quality.
Well...I was a musician for years until carpal tunnel stopped me, and NONE (as in zero-zilch-nada) of the many guitar players I knew and played with ever used anything but pro gear for practicing or performing. In fact many of then had their guitars and amps tweaked by pro shops to get the particular sound they wanted. And yeah, some of us tried the "play through the home stereo" thing at one time or another for various reasons, but as I already stated, it's just not the same, something was always lacking.
Mike
Mike
My current equipment consists of a 1981 Carvin X100 tube amp (12ax7/6l6gc -- Celestion speaker) and a 1974 Gibson Les Paul Custom. As we say where I come from: It don't get no better den dat.
The Carvin Museum - 1981 Guitar Amplifiers
I have made a few pedals in the past and I enjoy learning and experimenting with electronics. I don't expect anything I build to compete with my X100. I appreciate all the helpful replies.
A hifi power amp can be used with a guitar, but I can't imagine a hifi preamp being used. If that were OK sounding, then half the guitarists would just plug their instrument into the PA and listen to it on the monitors.
That's what DI boxes do , not what Guitar Players do 😛
In fact one of the most common nightmares for a Guitar Player is to have an amp breakdown and having to plug straight into the PA`(through a DI box, of course)
They don't even want to send the standard Line Out found in a real Guitar Amp, go figure, much prefer to mike the cabinets.
Two of the very few accepted ways to send a guitar to PA`without a full blown amp and cabinets (even if a humble Champ: 5W RMS, 1 knob, light 8" speaker) are:
Marshall JMP1:
not exacly a simple Direct Box inside:
Mesa Boogie Studio Preamp:
or at the very least:
which still is way more complex than a DI box, because it MUST process the guitar sound:
I know players who in an emergency have plugged a distortion pedal straight into a DI box, to at least have *some* grit and Guitar specific EQ .... they are still flogging their own backs in self punishment.
Just as a side note, this is Hughes and Kettner's Red Box, the most respected Guitar DI one , includes a Marshall 4 x 12" cabinet simulator ... and yet is meant to be used after a Guitar Amp speaker out ... worst case after its (fully processed) line out:
Notice it ONLY has Speaker and Line inputs, not a direct Guitar one.
In fact one of the most common nightmares for a Guitar Player is to have an amp breakdown and having to plug straight into the PA`(through a DI box, of course)
They don't even want to send the standard Line Out found in a real Guitar Amp, go figure, much prefer to mike the cabinets.
Two of the very few accepted ways to send a guitar to PA`without a full blown amp and cabinets (even if a humble Champ: 5W RMS, 1 knob, light 8" speaker) are:
Marshall JMP1:
not exacly a simple Direct Box inside:
Mesa Boogie Studio Preamp:
or at the very least:
An externally hosted image should be here but it was not working when we last tested it.
which still is way more complex than a DI box, because it MUST process the guitar sound:
I know players who in an emergency have plugged a distortion pedal straight into a DI box, to at least have *some* grit and Guitar specific EQ .... they are still flogging their own backs in self punishment.
Just as a side note, this is Hughes and Kettner's Red Box, the most respected Guitar DI one , includes a Marshall 4 x 12" cabinet simulator ... and yet is meant to be used after a Guitar Amp speaker out ... worst case after its (fully processed) line out:
An externally hosted image should be here but it was not working when we last tested it.
Notice it ONLY has Speaker and Line inputs, not a direct Guitar one.
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Nigel, Fahey gave a much more detailed reply, but guitarists rarely use a DI box right off their instrument unless it is an emergency. Direct lines to the PA from a guitar usually come off the amp, so as to include the preamp contributions at the least, and even better guitar DI boxes allow the user to insert them in the speaker line for even more complete tone. And some boxes, like Juan's Red Box include a speaker emulator to try to alter the signal as if it were run through a guitar speaker.
The one common exception to this is the bass guitar. The bass guitar signal is much more suited to a direct line to the PA than is the guitar.
The one common exception to this is the bass guitar. The bass guitar signal is much more suited to a direct line to the PA than is the guitar.
As do mine, although they are rarely used that way.
True, even more so for bass, but many guitarists are perfectly happy DI'd straight through the PA - I suspect a LOT of is the "emperors new clothes syndrome" from guitarists 😛
Obviously I wouldn't consider this for heavy metal, but for many types of music you're not looking for distortion and low quality. And even if you are, then a suitable effects pedal between guitar and PA will do a reasonable job (although I consider you need a heavily over-driven valve amp - NOT just a preamp - to do a decent job of it).
NO.
But that's not the point: an LM386 is widely available and costs 90 cents, and fulfills what you need, what's the point of not using it?
Even worse: even respected Tube amp maker Mesa Boogie uses an LM386 as it earphone and line output, so it's getting all the sound through it, whether for recording or reamplification:
Don't get why it's good for them (and all their High End users) and not good enough for you.
But that's not the point: an LM386 is widely available and costs 90 cents, and fulfills what you need, what's the point of not using it?
Even worse: even respected Tube amp maker Mesa Boogie uses an LM386 as it earphone and line output, so it's getting all the sound through it, whether for recording or reamplification:
An externally hosted image should be here but it was not working when we last tested it.
Don't get why it's good for them (and all their High End users) and not good enough for you.
red LEDs in guitar amp circuit
Could someone share as to what the purpose is of the 2 "red LEDs" that are in the following circuit?
http://guitarfxs.tripod.com/circuits/jade_1w_practice_amp.gif
Thank you,
yeto
Could someone share as to what the purpose is of the 2 "red LEDs" that are in the following circuit?
http://guitarfxs.tripod.com/circuits/jade_1w_practice_amp.gif
Thank you,
yeto
Sorry couldn't link to the post.
But along the lines of what you seem to want to do: Building a TL072 based preamp and then let some transistors do the "heavy lifting" of driving speaker(s).
Have a look at DOD 650 mini amp. There is a schem online. If you notice that the NFB is looped back from transistor output as part of the opamp feedback. Please use decent guitar speaker and not some 2'' cheap driver. And still nothing wrong with a chip amp build for starters. (Try both, learn & compare!)
But along the lines of what you seem to want to do: Building a TL072 based preamp and then let some transistors do the "heavy lifting" of driving speaker(s).
Have a look at DOD 650 mini amp. There is a schem online. If you notice that the NFB is looped back from transistor output as part of the opamp feedback. Please use decent guitar speaker and not some 2'' cheap driver. And still nothing wrong with a chip amp build for starters. (Try both, learn & compare!)
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