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SurfGuitar101 Forums » Gear »

Permalink My Surfy Bear PAM 8610 quiet amp :)

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I have used left over particle board parts from other projects. I'm aware that it isn't recommended for speaker cabinets. Smile I removed the fet-verb from one of my other Surfy Bear builds. I bought a WGS 8" speaker and an Accutronics short 3 spring tank. The PAM is an ebay item that was less than $3. I have finish work to do and right now I'm using 2 wall warts for power. I am going to get a laptop power supply that has enough power to run the amp, fet-verb and the trem when Mr. Surfy Bear has it available. The reverb color switch hasn't been connected yet. There is a blue led on the front panel that will be the on light when it's completed. Does it work? Yes. The reverb isn't as strong as it was so I have done something incorrectly. I will work on it later. I have other projects that I have to work on for a while. Smile
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Last edited: Jan 22, 2017 15:01:22

I think it looks super cool! I'd bet the sound will be very surfy. Great idea!

Once I'm good enough then I'd like to try making a similar combo.

I was hoping you'd do something like this. I bought a similar PAM board a couple of years ago thinking It might make a quiet guitar amp. I'm really interested to see how your project turns out. Nice work so far!

Awesome! My Duel Reverb Quilty Bear is being built today.

The Kahuna Kings

https://www.facebook.com/pages/The-Kahuna-Kings/459752090818447

https://thekahunakings.bandcamp.com/releases

Love the appearance of it! While not likely a problem at low volume with an 8", have an idea/pic for stiffening up particle board baffle if it turns out you need it. Stole the idea from Bill Machrone RIP at his site back when I had a slightly flubby Blues Jr.

That thing is really neat lookin'.

Wes
SoCal ex-pat with a snow shovel

DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.

How cute!
Where's the future space for the extra pots?
I hope you plan to protect those corners/edges. Disintegrating particle boards are not only an eyesore but hazardous to breathe.

Wow Wfoguy!!
Smile
Thats an interesting project, very cool.
Please report back what you think about the PAM circuit!

In no particular order, yes I don't think at low volume the particle board will be a problem. Yes all the particle board will be sealed up and finished somehow. When the tremolo is available, I plan to put it to the left of the output jack on the reverb. The pots will have to be on top. I thought I allowed enough room for all on the front but the knobs I used were larger than planned. My fault completely. This evening I did more testing. I have been trying to get it to run through both channels to the speaker. The speaker has tandem inputs so I doubled up on the wires going to the PAM. It would work for about a second and go silent. I was using a 1.2 amp supply. I went and got a 3 amp unit to try. That was the end of the board. Smile I'm glad these only cost 3 dollars. I think I received a defective board. This was using an mp3 player plugged into it bypassing the fet-verb circuit. Prior to this I plugged the fet-verb into my Vox. It sounded just as good as it ever had. And this was with the shorter 3 spring tank. That eliminated the Surfy Bear from the equation. I ordered several different PAM boards to experiment with as well as a TDA7297 board. The others haven't arrived yet. The "slow boat from China" hasn't arrived. Smile This is a short term setback. There are too many people on youtube that have used these. They haven't had the privilege of the fine Surfy bear products to make their world better. Smile I will continue to update this after more boards arrive. I'm confident this will end well. When I reach a satisfactory conclusion, I will list a materials listing, cost and suppliers. Smile

Last edited: Jan 23, 2017 18:49:24

Neat thing to follow; thanks for the comprehensive report.

Wes
SoCal ex-pat with a snow shovel

DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.

Ladies and gentlemen, we have an update! Good news and bad news. Smile The 1st pic shows the PAM8403 chip which is the smallest, the PAM8610 which failed and a TDA7297 board. You can see the TDA has the heat sink that is quite large. I connected the 8403 1st. It runs on 5 volts as usb. I had some static but no sound. That board didn't come with a volume pot so I think that is the answer. My box of misc. crap has nothing to help that. Next I was going to plug in the TDA. Because the 8610 had been fried, I robbed the 12v input from it. It says it needs a 2 amp supply. I 1st plugged in the 1.2 amp supply with only one channel. We have music! I connected the other channel and we were making popcorn noise. I plugged in the 3 amp supply and we have music. Smile I then connected the fet-verb and hooked up the jag. I wouldn't say the reverb is as strong as through a much larger amp but everything works. Smile I ordered 2 more of the 8610 amps to play with. I don't have space for the TDA as this was put together. I planning on the next 8610's to make all this work properly. If it doesn't , I'll have to mod the area where the amp will fit or build a new alum. top cover and relocate items until it all fits. The 2nd pic shows it powered up but the on board led is washed out by the light when taking the pic.
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Last edited: Jan 25, 2017 19:56:54

I have at least some more answers! I used the PAM8403 board this evening. The pics I uploaded are of the unit I'm using, and the makeshift connections I used. 1st and very important: As near as I can ascertain, all pam pcbs can not have the 2 output channels connected together period. If you would be using 2 separate speakers, you can connect both channels and live is good. Smile My amp speaker has 2 connections for + and -. Hooking the 2 channels together is not possible. The pam8403 is 3 watt per channel. We don't want to forget that the whole idea of this was a quiet amp. Smile Because I don't have a volume pot, I had to experiment with the connections that I have on the rear side of the board. The vcc and gnd appear to be voltage and ground. I found a schematic of a green board that showed using the inr and inl and gnd for a pot. The inr is one channel and the inl is the other channel. I tried various connections but the only one that works is tying the inr and inl together. I used the guitars volume to control the output. The fet-verb works reasonably well. The 5 volt adapter I used is less than .5 amp. On 1 site, it was recommended to use at least a 1 amp supply. I was satisfied that this could make a quiet amp and be ok. I'm waiting on 2 different pam8610 10 watt boards to arrive but now that I have more knowledge I'm confident that this will all come to an end soon after. I've been tempted to order a cheap decibel meter and compare the output of the different boards. Does anybody have any knowledge of a meter that might work?
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Last edited: Jan 26, 2017 17:52:17

Question: Many of the 3.5mm interfaces I see on miniaturized radio gear are - structurally - not the most robust in the world. In some cases they don't stand up very well to the larger form-factor cables and the downstream weight of the wire itself, often benefitting a little using a right-angle plug. Might not be any issue with your application but I was wondering how you regard the mechanical strength of the inputs on these boards in general.
Smile

Wes
SoCal ex-pat with a snow shovel

DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.

Badger, my thought is that the 3 I have seen so far are as strong as the pcb. However, my plan is for the board to be mounted and the output from the Surfy Bear going to the amp to not be removed on a regular basis. Only the input to the fet-verb is going to be used regularly. However, none of these parts would take abuse. For something that would see everyday use in movement, I would be concerned. The 8403 is so small that it looks like a toy. You have to be careful where you put it so you can find it again. Smile

Badger wrote:

Question: Many of the 3.5mm interfaces I see on miniaturized radio gear are - structurally - not the most robust in the world. In some cases they don't stand up very well to the larger form-factor cables and the downstream weight of the wire itself, often benefitting a little using a right-angle plug. Might not be any issue with your application but I was wondering how you regard the mechanical strength of the inputs on these boards in general.
Smile

This is a problem. Generally speaking, these amps are quite good but they seem to be designed to be mounted directly behind a very thin faceplate. I usually desolder the 3,5mm connectors and replce them with pins or wires. Sometimes I just solder the wires to the connector. If it's absolutely neccessary to keep the connector I snip a plug with its wire from a set of cheap earplugs. These are small and flexible enough to fit into a small space and don't put any stress on the connector.

Last edited: Jan 27, 2017 02:32:28

Like this:

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Minor update: home made vinyl label with color laser printer
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I wasn't happy with what I had done earlier in the day so I removed it and started over. I was using Microsoft Publisher which I used for the first time today. Smile I installed the TDA7297 board to power it up. I'm going to experiment with separate power supplies before combining all the inputs to 1 power supply. I have installed a terminal strip inside the case to facilitate connecting all components with ease for all the changes. When the Surfy Trem kit is available, it will be simple to connect into the series.
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Dig hearing of all your efforts. Poor amp; all Surfy Trem'd up & no date at the front door.

Wes
SoCal ex-pat with a snow shovel

DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.

Last update for the weekend. I filled all the areas of the particle board and painted them.
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Fantastic! DEMO!!!!

The Kahuna Kings

https://www.facebook.com/pages/The-Kahuna-Kings/459752090818447

https://thekahunakings.bandcamp.com/releases

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