# Using PedalPCB boards in place of Noisy Cricket preamp section



## Grubb (Aug 2, 2021)

One of the ideas I've been thinking about is building a small solid-state practice amp. I like the Noisy Cricket project at Beavis Audio Research. But it got me wondering about whether or not I could use a PPPCB board in place of the preamp section of the circuit. I really like how the Vertex Steel String Clean Drive sounds, and have a Six String Stinger board in the pipeline. Would it work to run the SSS board into pin 2 of the LM386 and then just have the rest of the Noisy Cricket circuit after that? Are there any other boards available here that might be suited for that kind of application?


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## temol (Aug 3, 2021)

Q1 is an input buffer, not a preamp. So you'll be fine leaving the circuit without any changes.


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## Grubb (Aug 3, 2021)

temol said:


> Q1 is an input buffer, not a preamp. So you'll be fine leaving the circuit without any changes.


Thanks for that. Would much change if I dropped the tone control out of the Cricket and only used the tone-shaping within the SSS?


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## Diynot (Aug 5, 2021)

Having done the whole cigar box guitar thing (before it was cool), I have built my fair share of 386 amps (run off groove little gem/little smokey). My experience is that even when run on 12v these little 1/2 watters have next to no clean headroom. Putting something like a boost pedal in front will leave you either sacrificing the tone shaping of the sss because you have to have the volume low, or having nothing but overdrive on the amp (it is a nice od sound though). If you still want to try your idea, try one of the bridged lm386 amps like the little gem mkII which pumps a full watt that way you can get some nice cleans too.


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## temol (Aug 5, 2021)

I'd keep the tone control. This way you can always use Noisy Cricket as a stand alone unit. But.. I'd rather look for aliexpres/ebay dirt cheap d-class amplifier modules. There's plenty of low wattage units.


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## Grubb (Aug 11, 2021)

temol said:


> I'd keep the tone control. This way you can always use Noisy Cricket as a stand alone unit. But.. I'd rather look for aliexpres/ebay dirt cheap d-class amplifier modules. There's plenty of low wattage units.


You have talked me out of the noisy cricket idea. I think class d will ultimately get me where I want to go. Now I've just got to work out which unit and how to integrate it. 🤔


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## temol (Aug 11, 2021)

You have several models to choose from. But first, you have to answer couple of questions. Do you need a battery powered amp? Do you have 9V supply only? Can you supply the module with higher voltage (12-24V)? Are you mainly interested in bedroom/night levels? 

I'd rule out the battery because of the cost and performance thing... 
9V supply - a bit low but might work. There are DC/DC step-up converter modules, so you can boost the voltage from 9 to 24V. But don't expect miracles because those cheap DC/DC step-up modules are often noisy.
1W aplifier can be pretty loud but it's easier to find 10-30W (or even 60W) d-class amp modules. They usually require 24V and 4ohm speaker in order to provide full power. With 12V and 8ohm speaker you can get around 10W (according to specs).

Take a look at this forum thread


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## Grubb (Aug 11, 2021)

I have a 1 SPOT CS12 so voltage is no issue, I can do 9, 12 or 18v easily enough. Bedroom levels are the expected application. I'm possibly the rare guitarist that doesn't enjoy loud! 

Thanks for the advice and the links.


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## temol (Aug 11, 2021)

If I can suggest two additional elements to the setup. Not mandatory but helpful when using d-class amp module. 

1. To avoid (sometimes) loud thump/pop when turning on the amplifier module it's good to have some kind of soft-start device between amplifier output and speaker. It's there to keep the speaker disconnected for a brief moment, at the beginning of the start-up.  The device usualy consists of several components and a relay. 

2.The  d-class amplifier has a flat frequency response unlike the tube amp. In order to give it some life I'd suggest using something like Amptweaker Depth Finder or it's diy alternative from freestomboxes forum member Bajaman called Presence and Resonance. In general, such device gives  a low frequency hump, and gradual high frequency rise, both with adjustable level. 
Here's a demo of the Depth Finder


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## fig (Aug 11, 2021)

temol said:


> If I can suggest two additional elements to the setup. Not mandatory but helpful when using d-class amp module.


Sorry to interrupt the outstanding counsel. @temol , would you happen to have the Depth Finder in a sim file? I think I'll try to put one of these together for someone (I have the schematic). Thank you.


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## temol (Aug 11, 2021)

fig said:


> would you happen to have the Depth Finder in a sim file? I think I'll try to put one of these together for someone (I have the schematic). Thank you.


Unfortunately I don't have a sim file. I do not even have a schematic of the DF


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## fig (Aug 11, 2021)

resonance_presence_build_doc.pdf
					

Shared with Dropbox




					www.dropbox.com


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## fig (Aug 11, 2021)

Well, that's not the actual Amptweaker version is it...


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## temol (Aug 11, 2021)

It's a similar circuit, not a DF. It's possible I have a ltspice sim file for this one. I'll PM you.


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## fig (Aug 11, 2021)

Apologies again for the interruption folks.


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