It's ugly, it's noisy....it's my DIY hybrid amp

[DankStar]

So this took me way too long, but at least the dumb thing works.





I got a Fender Frontman 15G for free only to find that it didn't work. I tried to troubleshoot it and got frustrated so I took out all the guts and decided to make my own amp.

The preamp is a Valvelitzer (low voltage tube booster): http://www.instructables.com/id/The-ValveLiTzer-Low-voltage-Tube-Booster/ I ended up at his version "V0.4" but with capacitor C3 at 47 uf instead of 100 uf. Seemed more midrangy/growly to me.

This part of the amp is awesome. I bought numerous 12FQ8 tubes off ebay and plan on making a stand-alone box at some point. It really does add a tubey-ness to the signal, and with an overdrive, goes into Marshall territory. I recommend this circuit to anyone wanting to make something with a tube but doesn't want to risk messing with high voltage.

The power amp is a very small dual LM386 board I got off ebay that puts out 1.5 watts. It doesn't sound too bad but it seems to be the source of a lot of my noise/grounding problems.

For a bit, I had both the preamp and the power amp powered by a 9V One Spot (sort of internally daisy-chained), but I had a lot of grounding noise issues that I couldn't get around. Part of this was in using plastic jacks that were not being ground to the chassis, but it seemed a larger problem was that the two circuits didn't like sharing the same ground.

After I separated them out (also upping the voltage to the power amp to 12V), now I hear a weird (low) noise through the power amp side, which I think is from a cheapo 12V walwart. Trying to see if I can live with that noise.

I still need to get some knobs and make some sticker labels still.

Features:
Front panel: preamp in, preamp volume, preamp gain, preamp bias (acts like a tone), power amp volume, preamp on/off

Rear: preamp out, power amp in, speaker out (disengages the internal speaker), power amp on/off, 9v jack for preamp, 12v jack for power amp.

Here's a clip:
I start clean with the stock speaker, then kick in the super OD, then switch over to a Carvin 2 x 12" cab.

https://youtu.be/5a2butiGggM

 

[justFred]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

That is the way to do man!!!Congrats on going outside the box...Amp Trek the next generation....

 

[MetalManiac]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Awful!








































Not the amp..your toes! The amp is cool! Great Job, it's a real winner.

 

[DankStar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Thanks dudes. Yeah, can’t live with the noise of the power amp side. Gonna figure something out & report back. May have to use a different circuit for that side, like a runoffgroove Ruby.

 

[Ayrton]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

I like it! The sound before the OD is my favorite

 

[Van Noord]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Nice! It's cool when a guy knows what he's doing and can play around with complicated sh¡t like that just for the hell of it.

 

[TwilightOdyssey]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Sounded fine to me!

 

[DankStar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

I like it! The sound before the OD is my favorite

It does sound pretty cool on its own, although rather low volume. If I can find a nice 12v adapter on par with a OneSpot I could squeeze a another dB or two out of it.

Nice! It's cool when a guy knows what he's doing and can play around with complicated sh¡t like that just for the hell of it.

I can't claim to understand every portion of it, but I have some fun trying! Some of it is kinda paint-by-numbers.

Sounded fine to me!

Thanks - the noise was one of those in-the-room deals where it drives you crazy if you're next to it.

------

FWIW - I ended up solving what was bothering me. I separated out the 9V jacks with separate grounds and now use a daisy cable with the One Spot to power both circuits.

 

[justFred]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Hey hombre, you inspired me to build a kluge amp: 12AX7 preamp like yours but I put a KT66 output tube in it so it does about 15W according to the calculation.


Sounds okay, even better than the Windows phone voice recorder used can capture...guess narrow frequence leaves it sounding mid heavy and flat:
starts with Texas Special neck at volume 5; moves to Pearly Gates bridge @10; then up to 12 for infinite sustain.
https://drive.google.com/file/d/1yNOYuAjycNf6h-4vmLTnjQ614X3zuf1X/view?usp=sharing

 

[DankStar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Hey hombre, you inspired me to build a kluge amp: 12AX7 preamp like yours but I put a KT66 output tube in it so it does about 15W according to the calculation.

holy smokes that's killer!

 

[Jeffblue]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Now that's what I'm talking about! People are inspiring other people. Cool projects. Don't ever give up and keep trying new things. I have no background and I am self taught and still learning. I repaired my 1968 Fender Vibro Champ when the output tube was red plating, changed out the cathode resistor, unfinished projects are converting a Carvin Bel Air amp from EL84s to 6V6s and a Mojotone Studio One amp kit that I need to troubleshoot.

 

[justFred]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Thanks dudes. Yeah, can’t live with the noise of the power amp side. Gonna figure something out & report back. May have to use a different circuit for that side, like a runoffgroove Ruby.

Any updates on the amp....am very curious how this project evolves...

 

[SAguitar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

"I love the smell of hot solder in the morning, it smells like victory."

You guys rock!

 

[DankStar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Any updates on the amp....am very curious how this project evolves...

I've been using the amp with a super OD into a mxr 6-band eq to dial in a rock/metal tone I like a lot. I'm going to keep the internal circuits as they are, and I ordered another 12V adapter (this time with a negative center to match the existing DC jack wiring) to run a few tests with.

 

[treyhaislip]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

Now that is a cool project. Great job!

 

[Phantasmagoria]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

That's awesome! Sounds pretty sweet to me too :bigthumb:

 

[DankStar]

Re: It's ugly, it's noisy....it's my DIY hybrid amp

slightly less ugly now. I'd still like to re-configure the power section but haven't had time.

used some silver marshall knobs - instead of a Jubilee it's a Hillbillee.

Actually I call it the “Lo-Hy” (low-watt hybrid amp)