Amp discovery!

[Kinski]

I haven't done anything new with these little amp boards but I still use the one I posted above all the time. Especially on tours and traveling. It out performs and sounds way better than my friends "Lunchbox" brand amp he bought.

[Kinski]

And just to be clear, this isn't my touring amp, haha. I use it in hotel rooms, bedrooms, etc. As a little yet powerful travel amp I can keep in my bag.

[rocket88]

i kinda went a little overboard compared to the 50watt board. i used a similar 100watt unit and built a solid state model t. runs on 110VAC that's converted to 24VDC. honestly, it sounds about as close to the real deal as you're gonna get without tubes. there's some subtle differences in the breakup, i've played the real deal, but really not enough to really make a difference. plus, since it's 100watt you definitely could use it for a gig. it's fucking loud, especially if you've got the gains up to 12 o'clock.



still got to make the cab for it.

[Kinski]

That is so damn cool. Great job!

[alltrax74]

I'm looking for a clean low wattage amp for my appartment to play with my pedalboard so I odered one yesterday

[BassVD]

Just found out about this topic, I'm wondering why  Anyway, thanks Travis for showing me the way!

I'm really triggered to build a Model T as well, so I've got a couple of quick questions for rocket88.
Did you change anything to the layout? I'm asking because a buddy of mine built the Model T pre and he said he wasn't really convinced of its sound (and he too played an original). But maybe it has to do with his setup, or something else I don't know about.
I want to use the amp at rehearsals, both with guitar and bass, so I need enough watts for some headroom. Any chance you're willing to tell which 100w board you used or where you ordered it?
What about ohms? What kind of cabs can you hook up to that board? Is there some way to implement a switch to select 4 or 8 ohms?
Did you use (extra) heatsink?

Cheers!

[rocket88]

So to answer your questions

1. Only change is I didn't use a switch to choose between channels, so the input goes to both channels simultaneously. I am running the preamp at a higher voltage which gives some more headroom and the FETs seem to behave more tube-like, so i also had to up the trimmers so I could bias it right.

2. Haven't tried my bass through it so i can't comment if it will sound good, but with my C-standard tuned les Paul it was an animal. It's 100watt a 2ohm, so using an 4 or 8ohm cab will get you less watts, but still more then enough I think if the gains are up, with the gains down it's fairly low even with the master maxed. remember it's SS not tube, so even though it's got 100watts it will be lower output then the real amp.

3. I'll have to look it up i think its a TPA3116 mono. The board is red.
edit: http://www.ebay.com/itm/DC-12V-24V-TPA3116-Mono-Channel-Power-Audio-Amplifier-Board-BTL-Out-100W-M-/172221184987?hash=item28192ebbdb:g:c10AAOSwzgBY24Di

4. No the amp does that automatically.

5. I hooked it up to both my mesa 4x10 powerhouse cab & my ampeg 2x10 micro svt cab and it worked fine. The 4x10 sounded louder naturally because there was more air moving.

6. No extra heat sinks the amp comes with one.

there's a few i've seen now that are 150watt but they have a preamp so they're not suited to build the mini amp.

[Kinski]

Hey rocket88, what voltage are you running the Sunn preamp at? And what value trimmers did you end up using?

[rocket88]

currently 24V, but looking at an effective easy way to raise it. currently i've got 50k trimmers in it to bias it right.

[Kinski]

Thanks. There is the 33v charge pump. Isn't the max voltage for a j201 about 40v or 50v?

[rocket88]

np. yea. i know about the chargepump i did make the layout. lol

i believe the j201 max voltage is 40V. the thing is too that the higher the voltage the more gain you get out of the j201, and tbh i think 24V is right on the money for this amp, as in more gain will make it sound less like the real deal. i'll try to make a clip of it when i've got some time at home next weekend hopefully so you guys can hear it. i sent travis a quick clip i took with my iphone and it doesn't do it justice, so i've actually got to break out a mic to record it.

[arkham00]

Hi, I just found out about this discussion from the tiny giant thread.

I'm quite a noob so I have some basic questions :

For IN and OUT which hole is for the sleeve and which one for the tip ? OR it doesn't make any difference ?

If I understand correctly I can still use a laptop power supply with this thing, right ? So I could directly solder the wires on the board
Otherwise I can solder a standard 2.1 dc female jack on the board and feed it with a standard 9v pedal adapter, do you know how many amp does it draw ?
Anyway It seems that it is better at higher voltages but I don't know how to try different voltages, I have a a 12v laptot supply, a 19v one and the standard 9v pedal supplies. Each has is own different jack,  should I cut the 2 laptop wires and solder a male boss jack ?

Is it possible to add a volume pot ? Maybe in the out section ? Can you explain how ? I'm not sure how to wire the lugs of the pot. And which pot ? how many K ? Lin or log ?

Thanks

[rocket88]

Hey man,

I'll address you're questions 1 at a time in order

1. You use the + of the in only to the tip of the input jack. The output you need to use both + and -, positive to the tip & negative to the ground. One caveat, you need to use closed jacks that are isolate from the chassis, you do NOT treat the ground lug as actual ground.

2. The max power the board can handle is 24VAC, so if the laptop power supply is at or below 24VAC you can use it. The higher the voltage the more wattage of the amp. So at 24VAC you'll get 50watt anti think 2ohm cabinate, higher ohm cabinate less wattage.

3. As far as wiring the DC jack, you need to wire it depending on if the power supply is positive center or negative center. If it's positive center then just wire it up as normal, if it's negative center then flip the wires.

4. I believe the amp can draw as much as 3Amps, but don't quote me on that. You can use higher amperage, and the circuit will draw only what it needs

5. I wouldn't hardware the laptop power supply, cause it will make things more of a pain to move it around. Just use a barrel jack that will fit the power supply out.

6. The volume pot will be the volume of the preamp in front of it or pedal in front of it. You could always wire a pot between the input and the in of the board. Input jack to volume 3, volume 1 to ground, volume 2 to + in on the board. If you want it at the output + output to volume 3, volume 2 to output jack. Not sure of size, but i would say linear. Probably anything between 100k to 1M.

[alltrax74]

WRT 6, I would go with 100k log pot at the output

[Travis]

On the input of the boards that I got there was one pad which was connected to ground (which I found by checking continuity with my DMM), and the other pad is the input. You can use the ground pad at the input to ground the shield of the input wire if you use shielded wire

If you are using the boards that Kinski used, the power supply is 12-24V DC. Many power supplies are unregulated and may put out more than 24V, so it will be important to measure that the voltage does not exceed 24V before you connect power to the board. The description of the board does not specify the current draw, but I have tried it with an 18V charge pump and it draws too much current to work with a charge pump. I will give mine at least a few amps of good regulated power to be on the safe side

[arkham00]

Wow, thank you for all the answers everything is clear.

I've got some other  questions, do I need to put it in a metal enclosure right ? It needs shielding like a pedal I suppose.
At first I was thinking to just screw it on the inside of my cabinet and drill a hole for the input jack, but I think this is not possible ... Or maybe if I glue some foil paper on the wood it will be enough ? like for guitars

I have a mono closed jack socket that i never used, I don't know how to wire since it has 4 lugs
like this http://store.synthrotek.com/assets/images/img_0587.jpg

which lugs do I solder, and which is which ? :)

For the output part is a jack required or can I just solder 2 wires attached to the small connectors which go directly to the speaker? I don't know the name here's a picture :)

http://blog.zzounds.com/wp-content/uploads/2015/12/Speaker-Terminal-Connection.jpg

For the laptop PS I checked the jacks and I think I'm very lucky since they are both the same size of a boss jack, and both are center positive, so no modification needed, I'll solder a pedal dc jack on the board and I will be fine.

Thanks again

[johnw]

I started using these boards about a year ago .I think they sound better with pedals than my other amps including tube amps, because the boards do not colour the sound at all.I wanted 2 inputs and more volumn so I got 2 tonemenders going into a mixer then into a splitter then into the two boards .They draw 48 watts each. However by the time I bought 19mm ply and dovetailed the head and the speaker cab it is not a cheap option. They run my 4x12 but in my speaker cab I have gone for a 10inch and a 12 inch to give me more punch, plus the 4x12s are to bulky my speaker cab is divided in two each side can either be open or closed back. The head had to be 400mm wide to allow for the spring reverb. I am using a laptop supply at 16 volts which I found better than 24 volts. Sorry to go on john.

[alltrax74]

I received the board today and plugged it.
Well, it won't be of any use for my taste.
Output is quite low, comparable to my 0,5w ruby, maybe just a bit louder.
But the major issue is that is sounds dark, too dark. I plugged my pedalboard into it and had to max all the treble pots to have something ok.
Definitaly not my stuff, the ruby sounds 10 times better.
For 5$ it was worth trying anyway

[Travis]

It sounds like you might have an issue. What are you powering the amp with?

[Kinski]

Yeah, that doesn’t sound right at all. Something is definitely wrong.