Amp project using TDA2030a's and tubes

[Taylor]

I don't think you're going to get anything interesting out of stereo by sending the same signal to both speakers. That's the same thing that's happening in any 2x10 or any multi-speaker cab. It doesn't need to be chorus, but you need to have two different signals going on for there to be any benefit.

[svstee]

It is two separate preamps and two separate power amps. The only thing they'll have in common is the power supply.

[Taylor]

Right, I get that. But the whole stereo thing depends on having different signals coming out of both speakers. Now, if you're designing this now with the plan to worry about what to put it into later, that's fine. But you keep saying you just want that stereo sound from a single instrument without effects. Such a thing doesn't exist. Even EQing the sides differently will probably not make for a stereo image, though it might make for a more "complex" sound.

I used to have a very complex stereo rig, with the speakers several feet apart, and EQ each side very differently (and the speakers were all different sizes) and it didn't sound  "stereo" until I used effects through it. You can do ping-pong delay, reverb on one side, none on the other, etc. but you will be disappointed if you expect there to be any fun spatialization with the same sound through both amps and speakers.

Nobody here wants to ruin your ice cream, I just would hate to see you put all that effort into it and not get what you want.

[svstee]

I don't think I'm comunicating the sound I'm going after here very well. I'm just trying to get a mory complex, multitextured full sound. I'm not expecting something I'd get out aof an elaborate stereo rig with FX loops for things like a ping pong delay or reverb on one channal. I just want something that sounds a little "more" for lack of a better term. Something with a slightly different sound. It will be stereo, but I'm not wanting (or expecting) it to sound too stereo is what I'm trying to say.

[km-r]

if you want to have a lil fun with stereo, try using a stereo synthesizer [generates stereo signal from mono using lo/hi-pass filters and phase shift]... you could also try varying the phase of the speakers you are using.

[Minion]

Maybe try something like this....



It has a tube pre with drive and overdrive controlls and it has 2 seperate outputs that have there own active tone controlls , definately not stereo but might help give you a fuller sound if you eq each differently and probably easier to buld than the roland ... I"m sure it can be improoved uppon but might be a good starting point ....

I"m building something simular accept not with 2 outputs but I am useing 2 tone stacks but in series with each other for greater boost/Cut , I"m useing two TDA7293 Chips in Bridged config for about 150w into 8 ohms and useing the Positive a negitive rails of the power amp to power the Plate of the tube to give it 64v DC and a seperate 12v transformer for the heaters and opamps .....

Cheers

[svstee]

OK, after looking at some different options I had a different idea. I came across this amp
http://www.aaroncake.net/Circuits/amp20w.asp
Using this chip
http://www.datasheetcatalog.org/datasheet/philips/TDA1554Q_CNV_2.pdf
It looks cheap to build, the only thing I don't have on hand is the chip itself. It also appears to be the perfect size for me. And correct me if I'm wrong, but I can power this from a wall wart, right?

[Morocotopo]

Svstee, regarding the stereo issue, maybe you should think about making two completely separate amps, that way you can graduate the "stereousness" by physically separating them more or less. I tried it, sounds nice, much more "open" and room filling than a single amp.  And if you need to travel light, just take one of them...
Regarding the amp you suggested, I don´t see any advantage it has over the TDA20x0 ones at GGG. And it doesn´t have a layout... I don´t see the advantage of powering an amp with a wall wart, one more thing to carry/lose/etc.

[waltk]

I'm a little late to the party, but here's my 2 cents... if you're looking for simple builds in a SS power amp, skip the chipamps that require a split power supply.  Do yourself a favor and look at the power amps designed for car audio.  There's a boatload of them out there, and they all run off of a single +12V power supply.  As a bonus, they often have good tolerance for other input voltages, and built-in protection against various short and overload conditions.

Here's a short list:

TDA2003 - 10W mono amp
TDA2005 - 20W bridge amp (mono or stereo)
TDA2009 - 10 + 10W stereo amp
TDA7240 - 20W bridge amp

So with any of these you could use a single wallwart power supply, and put any combination of (non-tube) stomp/preamp/tone/distortion circuits in front of it.  I just got a pile of TDA7240 amps in an Ebay auction, and I'll give you a couple if you want to attempt this.  Usually, the schematic provided in the datasheet is sufficient to a working model.  Of course, if you are still considering a tube preamp, you might as well choose any of the other chipamps because you'll be spending a significant amount your time/money designing/building the power supply anyway.

OK, stop reading here if you are easily offended by counter-DIY heresy.

There's another option if your are really looking for fast and cheap.  Buy any of the small, cheap, finished car audio power amps on ebay, and spend your time learning and building the stomp circuits as a front end.  As long as the back-end is just there to provide a clean power amp for your custom DIY-shaped tones - why fret over using something off the shelf?

[kamiwaza]

Funnily enough, I was planning to build a similar amp using two GGG LM3886 amps. My idea was to have a switching jack for the second amp so you could plug two guitars in for small practices or run one guitar to both amps. I was originally planning to use the AMZ Mosfet Boost as a pre but I might try the Tonemender instead. Heck, I might even do one of each.

My question is: If I'm using a split supply amp, how should I power the pre?

Cheers

kamiwaza

[svstee]

Regarding the amp you suggested, I don´t see any advantage it has over the TDA20x0 ones at GGG. And it doesn´t have a layout... I don´t see the advantage of powering an amp with a wall wart, one more thing to carry/lose/etc.

I like the idea of power from a 12v wall wart. I also want a small, easy to move stereo combo with one input. Also the aaroncake amp needs no separate power supply. Seems like a way easier build with a far lower parts count as well.
R1   1   39K 1/4 Watt Resistor   
C1,C2   2   10uf 25V Electrolytic Capacitor   
C3   1   100uf 25V Electrolytic Capacitor   
C4   1   47uf 25V Electrolytic Capacitor   
C5   1   0.1uf 25V Ceramic Capacitor   
C6   1   2200uf 25V Electrolytic Capacitor   
U1   1   TDA1554 Two Channel Audio Amp Chip   
MISC   1   Heatsink For U1, Binding Posts (For Output), RCA Jacks (For Input), Wire, Board

Can't beat that!

I'm a little late to the party, but here's my 2 cents... if you're looking for simple builds in a SS power amp, skip the chipamps that require a split power supply.  Do yourself a favor and look at the power amps designed for car audio.  There's a boatload of them out there, and they all run off of a single +12V power supply.  As a bonus, they often have good tolerance for other input voltages, and built-in protection against various short and overload conditions.

Here's a short list:

TDA2003 - 10W mono amp
TDA2005 - 20W bridge amp (mono or stereo)
TDA2009 - 10 + 10W stereo amp
TDA7240 - 20W bridge amp

So with any of these you could use a single wallwart power supply, and put any combination of (non-tube) stomp/preamp/tone/distortion circuits in front of it.  I just got a pile of TDA7240 amps in an Ebay auction, and I'll give you a couple if you want to attempt this.  Usually, the schematic provided in the datasheet is sufficient to a working model.  Of course, if you are still considering a tube preamp, you might as well choose any of the other chipamps because you'll be spending a significant amount your time/money designing/building the power supply anyway.

I like the sound of this, but how are they that different from the aaroncake amp? It looks like the one I'll do if no one sees any glaring problems in me doing so.

[panterica]

I'm a little late to the party, but here's my 2 cents... if you're looking for simple builds in a SS power amp, skip the chipamps that require a split power supply.  Do yourself a favor and look at the power amps designed for car audio.  There's a boatload of them out there, and they all run off of a single +12V power supply.  As a bonus, they often have good tolerance for other input voltages, and built-in protection against various short and overload conditions.

Here's a short list:

TDA2003 - 10W mono amp
TDA2005 - 20W bridge amp (mono or stereo)
TDA2009 - 10 + 10W stereo amp
TDA7240 - 20W bridge amp

So with any of these you could use a single wallwart power supply, and put any combination of (non-tube) stomp/preamp/tone/distortion circuits in front of it.  I just got a pile of TDA7240 amps in an Ebay auction, and I'll give you a couple if you want to attempt this.  Usually, the schematic provided in the datasheet is sufficient to a working model.  Of course, if you are still considering a tube preamp, you might as well choose any of the other chipamps because you'll be spending a significant amount your time/money designing/building the power supply anyway.

OK, stop reading here if you are easily offended by counter-DIY heresy.

There's another option if your are really looking for fast and cheap.  Buy any of the small, cheap, finished car audio power amps on ebay, and spend your time learning and building the stomp circuits as a front end.  As long as the back-end is just there to provide a clean power amp for your custom DIY-shaped tones - why fret over using something off the shelf?

What I'm working on right now is a TDA2009 10+10W stereo amp in a box for my laptop to sit on/plug into. Are there any preamps you would recommend for high quality sound out of my computer? I'm sure there's a million of them out there and in this forum, but I don't know if a guitar preamp (vs. a hifi preamp) would do the trick.

[waltk]

I like the sound of this, but how are they that different from the aaroncake amp? It looks like the one I'll do if no one sees any glaring problems in me doing so.

No difference... the aaroncake 1554 looks fine to me.  You would have to look at the datasheets to see if there was a difference in the specs that matters to you.  For my purposes, the biggest considerations are usually what I have on hand, or are easily obtainable at a good price, and low external parts count.  The 1554 seems to have a bunch of pins (to support quad amps), and is almost an inch wide.  The TDA7240 is smaller.  Maybe the 1554 is better for your purposes just because there is a schematic out there and you might be able to get support from whoever designed it.

What I'm working on right now is a TDA2009 10+10W stereo amp in a box for my laptop to sit on/plug into. Are there any preamps you would recommend for high quality sound out of my computer? I'm sure there's a million of them out there and in this forum, but I don't know if a guitar preamp (vs. a hifi preamp) would do the trick.

The answer to this question would lead the thread too far off topic.  A guitar preamp or stompbox circuit would be totally inapropriate for this application.  I would suggest looking in some of the DIY Audio forums that are more Hi-Fi oriented.