TDA1519B practice amp

[joecool85]

Thats awesome you got it working!  Thanks for all the updates, very good info!

[Brymus]

Let me guess, the two jacks below are speaker jacks and their sleeves short to chassis/ground?

Pretty much -You nailed it- one jack is the input the other is usually output when I build pedals or a spkr jack if its an amp.
I had forgot that they were uninsulated jacks (switchcraft)-therefore the input ground was connected to the output :duh
It didn't matter when the spkr needed to be grounded (single suply SE )or building a pedal.
But the load wasnt "floating" when BTL

I wish you guys knew how much hair pulling a cussing(3days worth) that little oversight caused me.
I am thankful I found it BEFORE frying my last chip.I was about to give up.
Again thanks for the info Teemuk I havent pinned my new schematic yet but am looking forward to your opinoin of the pre-amp I made on my own.(I actually calculated the knee points of the filters for it)

[J M Fahey]

Gosh ! Zap !  Boom !  :duh You mean all the time one of the chip "hot" output pins was grounded   :loco
Inkooreedibul !!!!!!
Well, thanks God you noticed it on your own, good for you.  :tu:
Anyway I still find that if *all* those other guys *do* have plenty of problems with this chip, they can´t all be grounding one of its outputs, especially if built from a kit, there must be some stability problem there.
At least I´ve never seen anybody complaining about the TDA2005, a classical and very popular BTL chip.
I don´t find it strange that it´s very popular with guitar amp builders, it´s used in the Fender AmpCan, Peavey Solo, Nobels Streetman, my own "Callejero", very probably in some of Crate's Hogs, etc.
Congratulations on your workbench, it´s much tidier than mine (no kidding)
Got curious about those beautiful lizard-skinned pedals, ¿what are they?
I´ll dig one of my TDA2005 powered Callejeros and post some pictures.
Hey, I found a few pictures of the small one (2 channel, 1x8", LeSon Tweeter,20W RMS, 12,6V 7AH gel battery, built-in charger)





They come in up to 100W RMS, 2x12"+Tweeters but even the 20W TDA2005 version is enough for many public places, including Subway stations, Bank halls and Mc Donalds type restaurants.

[J M Fahey]

Well, those pictures didn´t show up.
I'll try again:
http://s755.photobucket.com/albums/xx198/JMFahey/Callejeros/?action=view&current=Call2001.jpg
http://s755.photobucket.com/albums/xx198/JMFahey/Callejeros/?action=view&current=Call2002.jpg
http://s755.photobucket.com/albums/xx198/JMFahey/Callejeros/?action=view&current=Call2003.jpg
http://s755.photobucket.com/albums/xx198/JMFahey/Callejeros/?action=view&current=Call2004.jpg
http://s755.photobucket.com/albums/xx198/JMFahey/Callejeros/?action=view&current=Call2005.jpg
Hope it works

[Brymus]

HEY JM   :duh I KNOW I MEAN CRAP  :lmao:
Yeah it was that simple...

DUDE I love that little Calle amp thats SO SWEET looking!!
DO you mind sharing the schemtic and power supply set up?
It sounds like you have already pioneered what I am trying to do- AWSOME rechargable
with built in charger- I am months and months away from that.
But that has been my goal with moving into chip amps away from pricey tube builds.

I do plan on getting some other TDA chips the 2003,5,6,9 -2030- 2050 -7265(50watter)
When I can afford another Mouser order

Oh thanks on the pedals ,those are a few TS type clones,A RF drive from SEwatt.com, an ROG Omega ,a FF design based on the ROG Sili faceII,a 5 band EQ(not finished),
And a version of Gus Smally's "Rocket"
in the bin are a half dozen completed and tested FF builds waiting for enclosures.
If you look in this pic you will see the amp I built them for its- a remade version of my own using the EVJ platform,Hammond ESE OT, 10 watt EL84 ,Marshall/Fender tone with a Ghia tonestack.
http://i419.photobucket.com/albums/pp276/Bry928/EVJ%20Mods/augtooctober077.jpg

[J M Fahey]

Ok, no problem, PM with your EMail and I´ll send you the board and component side .
As an advance, here´s the actual populated board, both sides.
I only solder the TDA2005 pins *after* it´s actually bolted to the back panel, to minimize stress at the board pads.

[Brymus]

I was able to do some more testing.
My battery packs just dont have enough current for full volume.
I tried the supply (12VDC 3.2A)I was gonna use but its a switchmode based supply,LOTS of noise,
even with HUGE filter caps 
SO I will have to use something else the amount of volume was very suprising with 3amps available.
I mean it was louder and than I expected definetly close to 12 watts.
Using the 386 as a pre also gave more volume but I must not of had it coupled right as there was noise at certain levels.
Maybe a buffer between the output of the 386 and the tda input?

Also I tried a 4ohm load (3.7) for about 30 minutes and the difference was I didnt like the extra THD 10% 15watts-4ohm vs 1% THD 12watts- 8ohm
and the Really big heat sink actually got fairly warm so 6ohm(tested) is lowest for good sound and smaller heat sink from this chip.

I need to draw out the schematic at this point so I can get expert advice from you guys how to improve further.
All in All I am very pleased so far,I cant wait to try some of the other TDA chips.

[Brymus]

Here is the schematic of how it sits now-
http://i419.photobucket.com/albums/pp276/Bry928/SolidState%20Amps/12Watt-TDA1519B%20build/12WattTDA1519B_schematic.jpg
It has a fair amount of clipping going on it emulates an old tube amp fairly well IMO
It has a smooth overdrive going on,in the clean channel the louder you get.
The OD channel sounds good from a little diode clipping mixed in,(low gain)
to all out clipping from all the components.
The idea was to get some light clipping from the FETs as well,I think that is happening IDK for sure.
And to compensate for the loss of the tonestack,which helps tame the signal out of the op amp.
If I could change it it would be to get the clean channel -cleaner, maybe not possible with the 386 and this chip amp?
It evolved from this 2 channel Ruby build here http://i419.photobucket.com/albums/pp276/Bry928/Pedals%20and%20effects/SSamps/3862channelamp-small.jpg
I apologize for the hand drawn schematics the first one should be pretty legible though.

Any suggestions? Thoughts? Ways to improve?
Any critisisms welcome.

Also I plan to use two transformers so the pre and power amp have different supplies.
I will draw that out later.

[J M Fahey]

Hi Brymus, very good design.
I bet the sound is good too.
Good components/blocks combination.
The only thing that´s unnecessary is the buffer built around Q2; the signal coming from the previous unity-gain Op Amp is actually lower impedance as-is rather than going through Q2.
Congratulations.
Post some MP3s.

[Brymus]

Thanks JM
I will try it with out that buffer(Q2) and see about getting some sound clips.
I also want to try some other line in source (FX, another pre-amp)directly to the PA.
So I can better tell how much clipping is coming from the PA vs the preamp.
Alot of the clean channel overdrive(if not all) is coming from the 386 chip clipping.
A regular NJM386B would probably be better suited as well.
I also left the gain pots the abilty to overdrive the opamp if desired.
I got the master volume idea from you in another thread  :tu:

[joecool85]

I'd love to hear a sound clip, please post one if you can!

[Brymus]

OK the usual disclaimer -spinal injuries few years back(for real)carpel tunnel,bad arthritis
and I cant play. :tu: :lmao:    EDIT   Oh yeah and the clips sound worse off that server if anyone wants the original MP3s PM me
But the clips will give you a fair idea of the tone and what I mean by tube emulating.
http://vibecat.com/brymus

Recording technique- one channel is pencil condensor at spkr off axis,other channel is large diaphram condensor 3-4 feet out.
Cab 2X12  1XJensen Elec Lightning and 1XCrate Custom
Guitar Jackson Warrior Elite-Duncan humbuckers hot bridge(OD clips) jazz neck (clean channel clips)
Into Tascam US144-Mixcraft(cheap program)
NO EFFECTS OR COMPRESION the reverb is the room itself these tracks arent even EQ'd
All tracks tone control set in middle the master is at less than 30% except the first track Where both master and volume at 50%
Track1 Clean Channel-gain on 386 at minimum Fink Ployd
Track2 Clean Channel-gain on 386 at 30% Long cool Dress
Track3 Clean Channel-gain on 386 at 80-90%(max) SRV WannaBe
Tracks 1-3 channel gain at 30%
Track4 OD Channel-gain on 386 at minimum Tenacious B
Track5 OD Channel-gain on 386 at 40-50% MegaBrymus-1519Magix
Track6 OD Channel-gain on 386 at 80-90%(max) I'm not Jimi
Tracks 4-6 channel gain at max and volume at 80% master 30%

I revised the schematic. I will post it tommorow .It sounds right now.It could be adjusted for an even cleaner sound by lowering the value of one cap,I like it the way it is now.
I will post the revised schematic as well as suggested mods (clipping,EQ)and it should have the standby switch to prevent spkr pop(not bad really).
Anyone know a better MP3 hosting site?

[J M Fahey]

Hey Brymus: impressed by the sound(s) you get, but even more by your recording technique.
I never saw a better example of "keep it simple" giving such good results.
So let's see if I got it right: the main distorter is the LM386 itself, being helped by the first "distortion pedal" type preamp, and power-boosted by the TDA1519, going into a 2x12" box, picked by 2 condenser mics, a very close up one, the other at around one meter, everything happening into a quite live room.
Is that so?.
If that's indeed the case, wow!, the little humble LM386 is going places it *never-ever* thought would visit.
What we hear is the final result , of course.
If at all possible, post a picture of the recording session, so we can see the type of box, the speaker and microphone placement, etc.
O course please post your project in the "project contest" too, even if still on breadboard.

[Brymus]

You are absolutly correct JM,
I should also note I was using 12 AA Nimh for PA and a 9V for pre amp.
and thank you for the kind words.

[joecool85]

I got a chance to listen to the clips and they sound great!  On the first clip where it is all clean, is that going through the LM386 still?

I'm glad someone is doing this project btw, for about 2 years I've been thinking about doing a LM386 as a preamp and never got past plugging my little gem into my dean markley or lm3886 power amp (worked really awesome actually).