Amp in a pedal....

[Willybomb]

So, I've been tossing the idea of making a super small pedalboard amp for a while.  Plenty of people have already done, (Seymour Duncan, EHX, et al), but of course I have to fudge it my way.  I grabbed a couple of board off ebay, but this one seems to have worked REALLY well.

https://www.ebay.com.au/itm/373663516378

I'm powering it with a laptop power supply for about 27v, iirc.  Running my Mooer Preamp Live into from the 1/4 out has plenty of volume when the PCB is hooked up to a 4x12, lol - it kept up with drums with more to spare at praco today.  BUT, running into it from the out of a Effectlayout/Storyboardist JC-120 pcb is really, really quiet (and a little noisy).

So, I'm wondering what I need to do to fix that issue.  A boost (LPB1?) into a buffer before the amp maybe?

Quick vid as proof of concept....

[vizcities]

I'm literally building this exact Paladin/TPA3118 amp in the next few weeks - just waiting on an enclosure from Tayda - so I'm subscribing to this thread.

[Aentons]

Every laptop power supply I have used for audio has been noisy and somewhat interactive with whatever it was powering.

That board says it will run off 8V so I'd try a one spot just to see if it has anything to do with the power.

Cool jam btw

[Willybomb]

Every laptop power supply I have used for audio has been noisy and somewhat interactive with whatever it was powering.

I'm seeing people put a massive cap across the laptop +/- leads, like 4700uf.  I haven't tried that, but it's not hard to implement some filtering and/or regulating.

I'm literally building this exact Paladin/TPA3118 amp in the next few weeks - just waiting on an enclosure from Tayda - so I'm subscribing to this thread.

I'm planning on putting it in a DD with a Paladin and maybe an M800 or some other marshall preamp wired for 2 channels with effect loop, and dual outs (one with cabsim).

Cool jam btw

Thanks, can't claim it though.

[Willybomb]

One of these arrived today to try out...

https://www.aliexpress.com/item/33017016220.html

[jimilee]

One of these arrived today to try out...

https://www.aliexpress.com/item/33017016220.html

This just takes me to a sale page with lots of different items. What arrived?


Sent from my iPhone using Tapatalk

[Willybomb]

Odd. I followed the link and it worked. Basically, another little amp, this time 150w and about 2-3times the physical size of the first one.

[vizcities]

Interesting! I look forward to hearing how power amp #2 plays out. For my part, I may just bite the large enclosure bullet & build PaulInTheLab's power amp on vero:

https://paulinthelab.blogspot.com/2012/05/tda2030-based-amplifier-veroboard.html?m=1

Seems straightforward enough, & I have a handful of TDA2030s onhand...

[287m]

tpa311* sound is too sterile for me, but perfect for jazzman
tda20*0 always sound like practice amp
build lm3886 and push with whatever preamp you have, you can gig with that. Just search manfred post in fsb, he post layout too.

[Willybomb]

build lm3886 and push with whatever preamp you have, you can gig with that. Just search manfred post in fsb, he post layout too

Yeah, I've been looking at other solutions but then you're playing with 30-0-30 power supplies, transformers, and mains power which will bump up the size...  While I can do all that (and have done in the past), the point is to make the rig smaller.  The first pcb I was using in that video isn't much bigger than the input jack (it's *tiny*) and is pushing something like 50-60watts.  It's well and truly giggable.  Regarding the "sterile" comment, that's probably a fair comment but I'm using amp modelling and IRs anyway.

[Willybomb]

Ok, so as posted over at the Pedalpcb forum:

Ok. So, I picked up a secondhand 19v@4.5a laptop supply and hooked up the new "150w" board and plugged it into a passive wedge (measuring 10ohm, 12inch speaker and horn of some sort) that I have and compared it to the little blue "60w" board. The results are thus:

Big Red:
- Turning the volume up on the board will amplify an electric guitar enough to be heard, but it's not going to impress anyone or get louder than a conversation.
- Sticking an Effectslayout Paladin (JC120 preamp/DI) pcb in front of it works too, but the volume isn't still impressive.
- Here's the kicker. Sticking a buffer in front of it after the Paladin gives you an AMP!!!. All of a sudden, the Paladin volume is barely on, whereas it was well past 12 without the buffer and still not real loud. You get the same result using a buffered pedal (a Behringer fx600 in this case) after the Paladin.
- The buffer used was Paulinthelabs' Buffered Y-splitter, but I had the same result when that was followed by a klon buffer. It's a long story, but I was using the Terminus V2 DI that I built a couple of years ago. The chain inside is Y-splitter one goes directly out, the other goes to: - klon buffer - Sonic Stomp - Lart's Simple Cabsim. It's in the build reports here somewhere.

The results were a little different with the Little Blue One:
- The little blue one has next to no volume without the buffer. However, I couldn't get it to work with the DI/Cabsim after the Paladin - it just would not work. BUT, it did work with the FX600 in front of it (both with the effect on or bypassed) after the Paladin.
- Little blue does NOT like having the input cable inserted into the jack when it's turned on (I suspect it's the same with the output too). This will cause it to shut down and you will have to cycle the power to get it working again. However, if the input was fed from the FX-600's output and kept there, you can plug/unplug the fx600's input all day long multiple times without issue.

I noticed more noise with the 150w, but I have noisy power downstairs and it's always been an issue. I haven't opened them up as loud as they can go, but based on the size and experience on Sunday with the LBO, it's a winner. Stick it in a 125b (or smaller!) on the pedalboard and you're good to go. I have another 2 of them on the way.