PUNCH - 1W amplifier

[chromesphere]

The dual op-amps were probably for distortion?  The first punch amp I built was quiet.  I'm not sure what I did to stuff it up, but it was basically talking level.  The second one I built was loud! I was utterly amazed at exactly how loud (and clean) it could go! I could honestly p!ss the neighbours off, its that loud (through the 2x12 speakers).  I suspect there's something else going on with your set up, even without 2 x 12's you should still get something that's perfectly good for practice, maybe like, loud shouting level approx.

[shrike88]

Well, the good thing is I have it on a breadboard still. I'll investigate and maybe post some pictures.

[shrike88]

I think I found the issue (or at least a large part of it). The speaker has 4ohm impedance, not 8ohm. I only had an 8.2ohm resistor to the speaker. I changed it to a 12ohm resistor now. Similar problem though. I want to tweak things but don't want to wreck anything either

[Elijah-Baley]

I'm interesting about this mini-amp, but I'm having difficult finding a TDA7052. (Banzai, musikding, tayda...).
Or, there's a replacement?

[Luke51411]

Chromosphere has them in his store or else go to ebay. Make sure it is a tda7052A though, B won't work.

[Elijah-Baley]

I saw it in that store. 
On e-bay there's something indeed, but is not a cheap business. But I'll remember it.

I'm searching some in Italy, or Europe.
Maybe there's some TDA7052A, but with delivery costs a little expensive. I should order further product and get some advantages of that buying.

Thank you! 

[chromesphere]

Thanks for the mention guys!  Please excuse my following self-promotion, if you are looking for a pcb, my 'chime amp' is essentially a punch amp with a few minor additions , its also ridiculously small:

http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=1&products_id=84

Cheers

[shrike88]

My only issue is shipping to Canada. I prefer to build because it's much less expensive.

[chromesphere]

pcb + chip is $3 for delivery (untracked international mail post) just fyi. 
Anyway, I have about 50~ tda7052a's left incase anyone else needs em.

[shrike88]

That's actually quite reasonable shipping. I have a handful of the tda7052a chips I picked up off of eBay. That PCB looks pretty compact though.

[chromesphere]

Thanks Shrike.  Yeah the circuits so small, its an easy fit for a 1590a with a 9mm pot.

Did you fix the volume issue?

[shrike88]

No, it's still fairly quiet. I've double and triple checked the circuit and no dice. I may just take it all apart and try again.

[chromesphere]

That doesn't sound like its working properly, even with a small speaker I found this amp to be relatively loud.  With the 2x12's its 'shake the windows' loud.  Loudness is difficult to explain you know, but yeah, I definitely wouldn't have called it quiet.  The first one I built was very quiet.  So quiet if I was talking you'd have trouble hearing the amp.  I sort of thought "is that it!?" and moved on.  Then I came back to it a few months later and rebuilt the circuit.  I was totally amazed how loud this thing could go.  I mean its only 1 watt!  I concluded that I must haven't stuffed something up on the first one!  Just sharing this story because your situation reminds me of what I went through.  You might want to mess around with that resistor in series with the speaker as well.  TDA7052A only needs 8R on the output.

[Elijah-Baley]

[...] I prefer to build because it's much less expensive.

I prefer to build because it's much fun! 

I had built a very simple smokey amp, and I have some circuits work in progress. I'd like to build this one, too. I have just a tv speaker, 7 w - 8 Ohm.
Could I plug this amp into return of my 120w solid state combo amp 2x12?

[shrike88]

Well, despite my intent to rebuild the circuit regardless I put an order in for your chime amp PCB. I figure I get enough from your videos and assistance that I might as well contribute

[chromesphere]

Thank you very much Shrike will post out for you shortly, cheers!
Paul

[Elijah-Baley]

Hi! I'm ready to order the material for this building.
A friend of us had shown me this link: http://parasitstudio.weebly.com/stripboard-layouts/chime-amp-punch-amp-v2.
I need help (about some little mods) and some answers, please.

- I had a tv speaker (8 Ohm, 7w). I think that is fit. It is?
- I want to add also an output jack. I don't have a cabinet, but only a solid state amp 2x12. Could I connect this 1w amp to the return of my big amp? Eventually, I need some wiring layout about this adding, too.
- I'll put all into a plastic box. Generally, I always use open frame jacks. Is those fit in this case?

Thank you very much!  

PS
I read, about this layout, 1n5457 is absolutely necessary, so it can't replace. Is it true?
And, http://imgur.com/URTeFuF, might I need a protection 8 Ohm resistor for the speaker?

[petey twofinger]

you could take a look at the datasheet for the 7052 chip , this often helps with info

the chip is not more than 2 watt out put and 8 ohms is also good for the speaker if the datasheet supports this claim ... , ultimately the speakers ohm rating will effect the performance a bit , volume wise . for guitar amp speakers , some folks claim a small diameter cone is best . i feel trying out what you have  , experimenting with a few may be a good approach . having the speaker in a proper cabinet or box is extremely important , this makes a huge difference , the dimensions of said box , material , ported / not ported etc . that ALL plays a large part the toanz . especially if the speaker is not in an enclosure , they do not perfom well like that . in a test mode i have quicly prepared card board boxes to temporarily  house a speaker . it isn't permanent , but it will give me a much better response than a speaker hanging by its leads , or in the toilet .

i would not connect it to the return , but directly to the 2 x 12 amps speakers , after i "ohm the speakers out" to see what the impedance is , does that number support the spec in the datasheet ?  it may not harm anything , it may even sound ok , but it is not the proper method as you would be feeding the punch circuit into the other ones power amp . it also COULD damage something if it was cranked , etc ... not sure .

you may experience a bit more noise or interference with a plastic box , you may not . it would depend , but usually folks use metal enclosures to block rfi ( radio frequency ipod ) . some folks will insulate a plastic or wooden enclosure , there are "$pecial" paints , some use tinfoil if there is any left after the hat making , of course ,  copper tape , thrifty diyers prefer slug tape . i think this is why most folks choose a metal enclosure . you could try it and see ... this is the fun of diy , doing it wrong . ( my new sig? )

as far as the 1n5457goes , i believe any jfet should work , j201 , in my experience , well , i much prefer using a buffer in front of these type of chip amp circuits . unless you have  a buffered pedal that you would ALWAYS be using in front of the amp ...

again , the R in question , it is not a necessity , it depends how attached you are to the speaker , but me , personally , i would try it both ways  , as i have a ton of junk around , and i prefer to d o things "myself" as it may be , at times .

[chromesphere]

Don't use a J201 in this build.  It wont work.  TCA explained the reason why, vgs too low or something.  I built one with a j201 and it distorted.  I would socket the jfet if you are going to try one that isn't a 2n5457.
Cheers
Paul

[Elijah-Baley]

you could take a look at the datasheet for the 7052 chip , this often helps with info

I'll take a look, and I hope to understand something.

ultimately the speakers ohm rating will effect the performance a bit , volume wise .

I read it, too.

having the speaker in a proper cabinet or box is extremely important , this makes a huge difference , the dimensions of said box , material , ported / not ported etc . that ALL plays a large part the toanz . especially if the speaker is not in an enclosure , they do not perfom well like that . in a test mode i have quicly prepared card board boxes to temporarily  house a speaker . it isn't permanent , but it will give me a much better response than a speaker hanging by its leads , or in the toilet .

Ok, thanks! This is one of my first building, just for some experiments yet. I have little money and few material. So, that will be not a great amp or a mean amp for me. If I can make to work that is a success for me.

i would not connect it to the return , but directly to the 2 x 12 amps speakers , after i "ohm the speakers out" to see what the impedance is , does that number support the spec in the datasheet ?  it may not harm anything , it may even sound ok , but it is not the proper method as you would be feeding the punch circuit into the other ones power amp . it also COULD damage something if it was cranked , etc ... not sure .

I have just my combo amp. No way to play with the speakers without pass through amp.  
I could buy a cheap 8" or 10" speaker for the punch, if I like it.

you may experience a bit more noise or interference with a plastic box , you may not . it would depend , but usually folks use metal enclosures to block rfi ( radio frequency ipod ) . some folks will insulate a plastic or wooden enclosure , there are "$pecial" paints , some use tinfoil if there is any left after the hat making , of course ,  copper tape , thrifty diyers prefer slug tape . i think this is why most folks choose a metal enclosure . you could try it and see ... this is the fun of diy , doing it wrong . ( my new sig? )

My Smokey Amp is out of the box now, and that doesn't give me no problem with radio interference.
Plastic box I found are less expansive than metal box... I'll search again something better. Metal box.

as far as the 1n5457goes , i believe any jfet should work , j201 , in my experience , well , i much prefer using a buffer in front of these type of chip amp circuits . unless you have  a buffered pedal that you would ALWAYS be using in front of the amp ...

I found the 1n5457!   Finally. So, I'll buy this, and I will feel safer.

again , the R in question , it is not a necessity , it depends how attached you are to the speaker , but me , personally , i would try it both ways  , as i have a ton of junk around , and i prefer to d o things "myself" as it may be , at times .

Ok, I could add this resistor. I have to understand if I am one of that junk  . Indeed, I don't know how much ways are to attach a speaker!   Ok. I am a junk!  

Don't use a J201 in this build.  It wont work. [...] I would socket the jfet if you are going to try one that isn't a 2n5457.
Cheers
Paul

Thank you. I found the "right" transistor. 1n5457. And, of course I'll socket the transistor. Always!

PS Oh.... and about the wiring? (speaker + output cabinet)
I found some schematics, but there's something I don't understand. What kind of jack I need? And how to connect it exactly?
Thanks at all!