Author Topic: PUNCH - 1W amplifier  (Read 129687 times)

seadi123

Re: PUNCH - 1W amplifier
« Reply #360 on: September 26, 2017, 06:57:48 AM »
Quick question: I connected 5 to speaker+ and 8 to speaker- , however the - on the jack is automatically connected to the encolusure, which is connected to the ground. So 8 is connected to speaker- and ground, the speaker is muted. How do i get around this? Do i put electrical tape around the jack where it touches the enclosure? Thanks

PRR

Re: PUNCH - 1W amplifier
« Reply #361 on: September 26, 2017, 04:34:43 PM »
Electrical tape won't last.

Use a plastic jack, or purpose-made fiber bushings, or mount the metal jack in a plastic sub-panel.

kita

Re: PUNCH - 1W amplifier
« Reply #362 on: May 18, 2018, 01:37:42 AM »
Hi, sorry for bumping this topic but I'm having a really hard time figuring out what to replace the TDA7052A with.

I'm new to pedal/amp building so I figured a simple amp would be a good place to start. Unfortunately the TDA7052A has been obsolete for a while. The only place I can find them is ebay. Considering how prevalent counterfeit components are (I've had issues on other projects) I figured it would be safer to start with something that's still in production.

My problem is while I have a bit of experience with electronics, I'm still new to the audio side of things so I'm not super sure what I'm looking for. I've been on digikey trying to filter by what seem to be relevant characteristics from the TDA7052A chip and came up with the TDA8551. But I don't know enough to be confident that this would be a suitable replacement. Could anyone confirm that this would work? The only issue I can see is it has a max operating voltage of 5.5v, but other than having to supply it with the correct voltage, I'm not sure what else would be affected.

Another possiblity is the LM386 but I see a lot of negative comments about these so I'm skittish on it too.

Obviously nothing would be a direct drop in replacement. I'm planning on using the Punch's schematics to work my way back and make whatever changes I need to since I'm mostly doing this to learn afterall. I just want to know that I'm starting off with a usable amp chip.

Thanks and sorry if this is a stupid question, I'm pretty sure it is but I'm also pretty stuck.
« Last Edit: May 18, 2018, 01:39:51 AM by kita »

diffeq

Re: PUNCH - 1W amplifier
« Reply #363 on: May 18, 2018, 02:53:39 AM »
Hi, sorry for bumping this topic but I'm having a really hard time figuring out what to replace the TDA7052A with.

I'm new to pedal/amp building so I figured a simple amp would be a good place to start. Unfortunately the TDA7052A has been obsolete for a while. The only place I can find them is ebay. Considering how prevalent counterfeit components are (I've had issues on other projects) I figured it would be safer to start with something that's still in production.

My problem is while I have a bit of experience with electronics, I'm still new to the audio side of things so I'm not super sure what I'm looking for. I've been on digikey trying to filter by what seem to be relevant characteristics from the TDA7052A chip and came up with the TDA8551. But I don't know enough to be confident that this would be a suitable replacement. Could anyone confirm that this would work? The only issue I can see is it has a max operating voltage of 5.5v, but other than having to supply it with the correct voltage, I'm not sure what else would be affected.

Another possiblity is the LM386 but I see a lot of negative comments about these so I'm skittish on it too.

Obviously nothing would be a direct drop in replacement. I'm planning on using the Punch's schematics to work my way back and make whatever changes I need to since I'm mostly doing this to learn afterall. I just want to know that I'm starting off with a usable amp chip.

Thanks and sorry if this is a stupid question, I'm pretty sure it is but I'm also pretty stuck.

There are several issues with TDA8551, namely:
1. It has digital volume control and after power-up you have to send some number of pulses to control pin to turn the volume up.
2. Pinout of these are different

Sadly, LM386 is the only non-obsolete "just a 9V amplifier" 8-pin chip that you can find. I've looked into TPA1517, it's made by Texas Instruments, but it's bigger, it's stereo, and needs 12V supply minimum.

boppy100

Re: PUNCH - 1W amplifier
« Reply #364 on: May 18, 2018, 12:24:59 PM »
The Lm386 is tried and true and schematics and layouts abound on the web.  Look for the Smokey Amp,,it is just the lm386 with two capacitors.  It works, but.  Also, look at the Little Gem on the Runoffgroove website. I would suggest forgetting the 25K Master volume and replace with a 10k to 100k pot on the input.  You can also use a 1k to 10k pot for the gain, or leave pins 1 and 8 unconnected.

Another good chip is the TDA2822m, or L.  Renegadrian has a simple vero layout in the Layouts Gallery above.  Use the advanced search for TDA2822m.  This amp is cleaner and a bit more powerful than the Lm386 and works quite well on 6 volts or even with a 5 volt phone charger.

kita

Re: PUNCH - 1W amplifier
« Reply #365 on: May 19, 2018, 03:12:29 AM »
Thanks so much guys!

I'm not overly fussed about the voltage since I plan on running it from a power supply anyway, although the idea of running it off of a few 18650s is really appealing.

Going to order a few of all the chips mentioned and have a go trying out all those amps and maybe some random pedals while I'm at it. Thanks again!