Pedal based practice amp TDA 1519b

[Brymus]

Hi I know this isnt a pedal but the pre-amp was designed from pedals 
Its a 12 watt SS amp that sounds really good and is VERY loud with a good spkr.
It was inspired by the ROG,this forum,and SSguitar.com
Best of all its cheap to make...

Any feedback,critisism,ways to improve welcome.
I would like to get less distorion from the clean channel if anyone has any suggestions other than remove the 386 chip.

SCHEMATIC  http://i419.photobucket.com/albums/pp276/Bry928/SolidState%20Amps/12Watt-TDA1519B%20build/12WattTDA1519B_schematic.jpg

The TDA 1519b chip was purchased from Apex Jr while getting stuff for my lm3886 build (thanx RG)
http://www.apexjr.com/ -thanx Steve

[Mark Hammer]

Apex Jr is an interesting place.  I'd never heard of them before.  Thanks for the link.

[Brymus]

No problem Mark,His prices on transformers cant be beat!  Except by dumpster diving 
Any suggestions for the circuit?

[doitle]

That 120V to 50V and 6.5V transformer sounds mighty interesting... Sounds like a perfect power transformer for a lowish plate voltage tube amp.

[sean k]

I've been having problems with the 1519. I originally had a kit for the 1519A whih ran on 12V battery, big sucker, and mistakenly went and bought some 1519 (no suffice) to do it some more. To date I've been unable to get sound from the 1519 at 12V but gor some from it at 14.4V. I'm going to eventually put the 1519A back in, when I can find it, and go to 15V. I think its that the 1519's I got are all duds for some reason but it's been bloody frustrating. Maybe I just need to go buy some more 1519A's.

Just make sure you give them enough current and theres a trick out there that you can use a transistor bypassing the 1 amp voltage regulators.

[Brymus]

SEAN K
I read in Europian forums where others were having alot of problems with these chips.
My only problem was arrogence in overlooking a ground point,that interfered with the BTL mode not allowing the load to "float"
I think all the others having similiar problems (overheating ,bad sound) were noobs like me as well.
I know your not a noob I've read lots of your posts.
You can read about it here if you want a good laugh  http://www.ssguitar.com/index.php?topic=1212.0
I would suggest getting the 1519B over the A unless you want a stereo amp.
I found it likes a good 2amps at 12 volts or a 16V supply (learned about watts VS amps and volts through this )

I only paid .79 cents each at APEX jr for them and .39 for the NE5532 chips- He has bargains galore
His 25+25 watt amp looks like a good candidate for a guitar amp as well given its 19$

[sean k]

Umm, I didn't have the problem you eventually found was the culprit...oops. I'll look into that play Apex but I'm not in the US. You wanna get some for me and I'll send you some cash. Oh, I'll send you some cash and you get the chips for me then send them to me here in New Zealand. Would 10.00 US do it for you, given that your getting more stuff from him to fulfill the minimum order... or I could send you some of my pewter knobs... as a swap.

Hey Bro thanks for the credit but I'm just a hacker myself. I can figure out a few things but I've got my eyes closed and my hands out in front of me tenuously feelin' my way along. It more luck than sense that gets me anywhere.

[Brymus]

Sound clips here  http://vibecat.com/brymus
from left to right
Track1 Clean chnl 386 at minimum gain- Fink Ployd
Track2 Clean chnl 386 at half gain- Long cool dress
Track3 Clean chnl 386 at max gain(from pot)- SRV WannaBe
Track4 OD chnl 386 at minimum gain- Tenacious B
Track5 OD chnl 386 at half gain-MegaBrymus 1519Magix
Track6 OD chnl 386 at near max gain-I'm not Jimi
Yeah my playing uhmmm well....

And a revised (much better) schematic tommorow.

Uhm- Sean IDK when Ill be hitting up Apex Jr again but I will PM you if you want.

[Brymus]

Did anyone listen to the clips ?
For a battery powered amp that can keep up with drums for under 30$
This thing kicks ,endless tonal possibilities.
Or even as a pedal or headphone amp.
Not to mention the SRV clip nails an overdriven tube sound IMO

[dschwartz]

i did.. sounds amazing! congratz!!!!

[ItZaLLgOOd]

The clips sound great.  What kind of speaker/cabinet were you recording with?

[Brymus]

Hey thanks guys!
Its sounds even better now-
Here is the revised schematic for the pre-amp http://i419.photobucket.com/albums/pp276/Bry928/SolidState%20Amps/12Watt-TDA1519B%20build/386PreAmp_2.jpg

I need to record some new clean clips now to show the difference lowering the 330n in the opamps feedback loop makes,
Completely removes the flab without losing the sweet clipping character,and the abilty to get "breakup" with pick attack is much easier
to control now.
The cab is a 2x12  1 Jensen Elec Lightning and 1 Crate Custom
A pencil condensor is placed right on the Jensen off axis and the other channel is a large diaphram condensor about 3-4 feet back.
Provides a nice stereo and reverb effect,and allows to hear how the amp is projecting.
Yet it is still a dry track(no compression or EQ or anything else)

[ItZaLLgOOd]

Is U1B a buffer and does it work with out a resistor and half the supply voltage on the input?  Have you tried it with the IC buffer in front of the gain stage and no buffer before the tone/volume control?  Maybe the same tone with less parts?

[Brymus]

U1B is a voltage follower to drive the tonestack,
I hadnt thought of using it as the input buffer,I might see how that works.
I also need to lower the values on the present input buffer.
This is what I was looking for some feedback on the circuit...THANX

[Bubesz]

Sound good!

Is there any mod for using it with bass? It would be best to make it switchable...

[Brymus]

Thanx Bubz ,no I dint think about that.
Thats a good idea,or a mic input too might be nice.
I kinda just got lucky with it.I was suprised by the tone.

[Bubesz]

And could you make that mod? I heard that it's not much difference, in effect you usually only have to change some caps or resistors.

[davidallancole]

What kind of tone control is that?  I haven't seen that setup before.

[Brymus]

Hi sorry for the delay ...I had to think about it Bubz, but NO it wouldnt make a good bass amp.
The pre-amp is designed around guitar, the way it gets its clipping on the OD setting wouldnt sound great with a bass IMO.
The clean channel could be adjusted to allow more lower frequencies,but the TDA1519 chip has a low frequency roll off starting at 40 hz.
Not the best for low end reproduction.Works great for guitar.
So even adding another pre-amp channel for bass I dont think the chip amp would be good for it.

David Alan Cole -that tone control is supposed to be from a Dr. Z -Carmen Ghia amp.It came in my modded EVJ, That started me off into DIY electronics.And I have also heard from others that it is indeed that tonestack.I like the way it sounds -It turns the bass up as it cuts the treble and vice versa.

[Bubesz]

Ok then, I'll stay at the original idea But... I couldn't find a TDA1519B in my city, but the guy at the shop told me that the TDA1521is almost the same as 1519, but with more power. So can I use the 1521 instead of 1519 (which would make it a quite "serious" amp, I mean, loud enough for rehearsels)? Another question: in the shematics you have a +9V connection and a +16V as well. So you need to build a power supply with +9 and +16 outputs or you have to use 2 different adapters?