Fresh meat.

[DADDEO]

Hello one and all. As you can no doubt see, this is my first foray to this forum, and I shall ask, as I see fit, to ask stupid questions and generally seem a bit of a tit. Anyway, my knowledge of electronics is minimal but as an electrician I do have some idea of what's going on, and with the help of DIYAudioprojects.com, built a small stereo Mp3 amp with two Velleman K8066 3W kits. It's not pretty but it works.
My main passion though is the guitar, and as a budding bodger, have looked around the web and came across Runoffgroove's DoubleD effects pedal which sounds gorgeous and would make an ideal pre amp, but to be made into a head unit or combo would need a power amp.
Now, the more alert ones amongst you will know what's coming next so i won't keep you in suspense, what would be a simple power amp to construct for a beginner( different wattages, speaker impedancies and the like ).   

[J M Fahey]

You might climb the ladder one step at a time:
LM386 (1W) -> TDA2003/LM383 (8W)  -> TDA2030 (15W) or TDA2050 or LM1875 (25/30W) -> LM3886 (50W) -> the sky is the limit.
You will not *waste* time on any of them, when you build the next bigger one, the older one will still be useful .
Cost is very low.
Personally I would not skip steps, plus ... it's fun!!!

[polo16mi]

J M comes first, 

I had asnwer that...

Hi, welcome to the forum.

For kick answer:

If you looking for...

1W:  google for little gem (a circuit with a fet, a LM386, couple of resistor, capacitor, few work, and that´s it.)

around 15 W:  Look for TDA2005 datasheet, bridge circuit. It uses 12V, and work really god. Easy to mount. Few components too.

around 50W:  LM3886 is sure bet. Look in this forum or Gainclone at google.

Hope help.

Dont hesitate to ask.

[DADDEO]

Cool. Thanks for the replies. Are these amps " clean " or will they produce some distortion.

[J M Fahey]

They are all clean by themselves and faithfully reproduce the clean or distorted sound provided by your "Double D" or any other pedal you use to drive them.

[joecool85]

They are all clean, sterile even if you are talking about the LM3886.

Personally, I wouldn't hesitate to skip steps.  I agree with Juan that if you do all the steps you will still have useful amps...but I know I don't use all of my amps anymore really, just two.  Also, I've built LM386, TDA2003, LM1875 and LM3886 amps and they are all about the same difficulty level.

I would suggest if you only need a small 20w amp to save your money and get a Tiny Giant from MusicPCB.com: http://musicpcb.com/pcbs/tiny-giant-amp/

Or, if you want/need 50w RMS or so, go with a LM3886 kit from Brian at chipamp.com.  They are more expensive but work REALLY well.  Only downside is that you can't get a mono amp. You have to get stereo or dual mono.  Stereo means it has two amp boards and one PSU board that gets shared, dual mono has two amp boards and two psu boards (you could build two amps or build one and sell the parts of the other).

[DADDEO]

Nice link joe. It always amazes me seeing electronic circuits, has done since I was a kid. I honestly don't know why I've started to tinker with them now, must be a male menopause thing. Anyhoo, thanks for the advice everyone, hope to chat again soon. :tu: :tu: :tu:

[DADDEO]

Early last year I was working at a local school that was throwing some stuff out and I came across a large cassette player / recorder that was designed for use in language classes. I tried it out as a guitar amp but the hiss was terrible, so I thought I'd keep it for spares. Inside I have found two TDA 2040 op amps and a 9514 BD 438 transistor. Could I use any of these to create a worthwhile power amp for the DoubleD pedal / preamp. If so, what power could I expect through various impedancies.

Thanks

Jim.

[joecool85]

Early last year I was working at a local school that was throwing some stuff out and I came across a large cassette player / recorder that was designed for use in language classes. I tried it out as a guitar amp but the hiss was terrible, so I thought I'd keep it for spares. Inside I have found two TDA 2040 op amps and a 9514 BD 438 transistor. Could I use any of these to create a worthwhile power amp for the DoubleD pedal / preamp. If so, what power could I expect through various impedancies.

Thanks

Jim.

TDA2040 has a maximum of 16w at 8ohms and 28w at 4 ohms.  I'd consider using those for a power amp.  Bridged they are rated for 30w at 8ohms but I think they could put out more since that is only at +/- 16v.  The max for 4ohms of 28w was at 18v.  I'd be willing to bet you could get a solid 40w by bridging it at +/- 18v.  Maybe a tick more.

That said, I'd consider running them as a dual mono.  Two power amps fed off the same preamp driving two separate speakers or cabs.  Or you could do it as a stereo amp.  Some guys like that for chorus effects etc.  That would give you up to 2 x 28w.  Plenty of power for small to medium gigs even.

[DADDEO]

Holy cahones BatBloke !!!. That's sweet. Thing is how would you bridge these in a circuit bearing in mind I'm still a thicko at at this stuff. :lmao:

[joecool85]

Holy cahones BatBloke !!!. That's sweet. Thing is how would you bridge these in a circuit bearing in mind I'm still a thicko at at this stuff. :lmao:

Like I said, I wouldn't.  But if you want to the circuit is drawn up on the datasheet.  Just search on yahoo or google for "TDA2040 datasheet" and you'll find it.

[bry melvin]

Might want to look at schematics for Fender frontman 15 amps and crate Gx30M....they both use TDA20x0 chips. Currently Fender used the TDA2050 but at voltages established for TDA2040A

[joecool85]

Might want to look at schematics for Fender frontman 15 amps and crate Gx30M....they both use TDA20x0 chips. Currently Fender used the TDA2050 but at voltages established for TDA2040A

Well this Genz Benz I've been working on has been running +/-27.5v on a TDA2050.  +/- 2.5v past it's absolute maximum rating...quite possible that's why it fried itself.

[bry melvin]

voltages established for TDA2040A

actaully thast was a faulty memory that was a crate amp i worked on  Fender uses +-22

[joecool85]

voltages established for TDA2040A

actaully thast was a faulty memory that was a crate amp i worked on  Fender uses +-22

Ah.  That's fine.  It seems that many manufacturers do really push the voltage limits though.  My K20-X runs +/-18.1v and I think +/-18v is the max for the TL072 in the preamp and I know +/-18v is the max for the TDA2030 in it.

Nothing like running on the bleeding edge for that extra 1/4w of output.