I Want a cheap and easy "Confidence Builder" amp kit.

[Guitarist1983]

I'm new here; joined this forum today. Could someone please direct me to the easy, "Your First Amp Kit" forum/thread?
Thanks.

[echuta13]

I'm not sure if there is one here?
Make sure you do some research on different kits before you buy though! Two amps I would suggest that are easy builds would be a 5F1 Champ, or 5F2a Princeton (I'm a fan of the 5F2a).

There are some great kits out there. I can't say I've built more than two kits, but I wouldn't hesitate to recommend buying from either of these companies:
https://www.trinityamps.com/
http://www.allenamps.com/index.html

[J M Fahey]

Have you built anything before?
If not, do not start with a Tube amp, deadly voltages involved.

One proper and safe "starter" staircase, to be climbed step by step, would be:

* Start with a Ruby

Killer sound, very useful, and most important : lots of data about the project, videos, etc:

https://robrobinette.com/How_the_Ruby_Amp_Works.htm



https://timothylaux.com/project/lm386-guitar-amplifier/



* AFTER you successfully built it or a similar project, THEN you may try to build a Fender Champ

https://www.mojotone.com/kits/TweedA...-Champ-Amp-Kit

https://www.tubeampdoctor.com/en/twe...-style-amp-kit

these are relatively expensive because they are exact clones of a famous and revered amplifier, down to the last nut and bolt, including original clone cabinet, covering, speaker, etc.

But you may very well just build the chassis, no cabinet or case (at the beginning), just the electronic part and use it with any speaker you have.

After it works properly, you can start thinking about cabinet, speaker, etc.


OR: build its modern "Open Source" version, an AX84

Excellent amplifier, built by thousands, very well documented:

https://ax84.com/archive/ax84.com/p1.html

FWIW my first tube Guitar amplifier was a Gibson GA-5, their version of Champ.

I only had the schematic (straight from Jack Darr´s book which I recommend you read, there´s a downloadable PDF copy on the Net) BUT I already had a couple years experience building other Electronics stuff, model cars and planes, repairing bicycles, etc.

That helps a lot, it´s not just "soldering" but some mechanical assembly, drilling chassis (unless you get the expensive kit with a predrilled , painted and labelled one), mounying pots, transformers, wiring, etc.

[loudthud]

As far as tube amp kits, it can't get much cheaper or easier than this: https://www.tubesandmore.com/product...itar-amplifier

[glebert]

As far as tube amp kits, it can't get much cheaper or easier than this: https://www.tubesandmore.com/product...itar-amplifier

I can beat that. Actually when you include the chassis the cost is pretty much the same.
http://www.kldguitar.com/KLDguitar-E...uitar-amp.html

That one might be out of stock, this is another one.
http://www.kldguitar.com/KLDguitar-E...uitar-amp.html

I think Dan Thompson from the Guns and Guitars Youtube channel built the Pilot 15 on one of his videos. Super easy.

[Chuck H]

Well there are things we DON'T know, but should.

Does Guitarist1983 already have some electronics experience? And...

What sort of tone would Guitarist1983 find gratifying in a first build?

If there's already some electronics experience and ability to decipher schematics then shying away from a slightly more complicated build isn't necessary. But this is a key issue because troubleshooting gremlins on anything more complicated is a nightmare for completely green DIYers and we here alike when trying to extract/interpret/decipher the critical information. So, nothing other than simple amps for greenies

That means that a higher gain amp is out of the question unless there's prior electronics experience. If Guitarist1983 would only be happy with a high gain amp, but doesn't have experience and understand schematics the project is moot.

I started out very young modifying my gear. I already understood some things when I took on an amp "modification". Then I did several amp modifications before I ever ventured into building a whole amp. And even at that point I still didn't understand every aspect of the whole circuit so troubleshooting was difficult. That said...

If Guitarist1983 has a little experience and wants a good tone that will crunch up a little and take pedals well then a basic 5e3 or one of the many 18W kits would probably be great.

But we don't know the how the limitations (?) stack up to the goal (?) yet.

[Guitarist1983]

Well there are things we DON'T know, but should.

Does Guitarist1983 already have some electronics experience? And...

What sort of tone would Guitarist1983 find gratifying in a first build?

If there's already some electronics experience and ability to decipher schematics then shying away from a slightly more complicated build isn't necessary. But this is a key issue because troubleshooting gremlins on anything more complicated is a nightmare for completely green DIYers and we here alike when trying to extract/interpret/decipher the critical information. So, nothing other than simple amps for greenies

That means that a higher gain amp is out of the question unless there's prior electronics experience. If Guitarist1983 would only be happy with a high gain amp, but doesn't have experience and understand schematics the project is moot.

I started out very young modifying my gear. I already understood some things when I took on an amp "modification". Then I did several amp modifications before I ever ventured into building a whole amp. And even at that point I still didn't understand every aspect of the whole circuit so troubleshooting was difficult. That said...

If Guitarist1983 has a little experience and wants a good tone that will crunch up a little and take pedals well then a basic 5e3 or one of the many 18W kits would probably be great.

But we don't know the how the limitations (?) stack up to the goal (?) yet.

Good questions. First, my apologies as I learn the ins and outs of this forum. As to my background:
33 years in embedded software engineering--controlling hardware systems such as VCOs, power supplies, control panels, antennas, gain optimizer systems, receivers, etc. Trained in soldering, with limited experience--primarily populating circuit boards, also guitar electronics mods, built a dozen guitar pedals from kits and then modded. Experience with spectrum analyzers, o-scopes, digital-circuit/timing analyzers. I can read schematics, though I have to look up parts regularly to understand their full capabilities and limitations (e.g., specific op amps, diodes, etc.).
I have never modified or repaired a guitar amp, but I have experience draining charged capacitors without sparks and pops (using a 10w, 100ohm resistor and verifying with a multi-meter).

I like clean-to-medium breakup amps: Fender amps on 7 sound great. Vox circuits sound great, too. I'm not a high-gain guy. I own a Fender Princeton, Morgan AC20Dlx, and Silvertone Twin Twelve. I get dirt from pedals--Timmy, Klone, TS808, etc.

As a first step into the world of amp building, I would be open to modifying/servicing my Silvertone, but it is ugly, ugly on the inside--like a bowl of tangled spaghetti. The Princeton is the PCB Reissue model, which doesn't look very serviceable for a newbie, and the Morgan is too expensive to mess with as a first project. Anyway, thanks for reading this far, and all recommendations are very much appreciated.

[Chuck H]

Alrighty I don't think you'll have much trouble building any circuit that meets your tone criteria. So, is there anything you'd like to have tonally that you don't have now? More watts? Less, so you can crank it a little without scaring the dog ? Maybe you've considered adding something more Marshall-y to your collection?

I think any kit for for a vintage style design would be in your wheelhouse. And they're all very similar in their circuits at face value. A couple of gain stages for a preamp, a phase inverter, a pair of power tubes and a power supply with a basic TMB tone stack somewhere in the preamp. I think choosing a kit with a layout that looks more understandable and serviceable (than a plate of spaghetti) is a good idea because it would allow for easier troubleshooting or modification if you want to fine tune the sound.

I don't really know much about available kits since I sort of skipped that step in my process. But my points above are:

1) I don't think you're limited to a super simple plug part A into part B kit. So...

2) Consider what you REALLY WANT, describe it here and I'm sure the members will come up with some good suggestions.

[tedmich]

Juan, as usual, has given you excellent suggestions!

Once you've "cut your teeth" on these simpler projects you may want to find an unfinished Mesa DR clone kit from the (now defunct?) Russian enterprise Ampclones.com!

How many of these remain unfinished? A good question, how many were sold?

[Guitarist1983]

Update: I went super easy and built the MOD 102 Amp Kit. It works, instructions were clear, assembly was easy, a few tight spots for soldering, but easy. But I now have questions concerning its theory of operations for anyone willing to teach.
I do not understand why the EL84's cathode is connected to the 6VAC tap of the PT in parallel with a resistor to ground and a cap to ground. Explanations appreciated.

[Helmholtz]

That's a trick called heater elevation. The constant DCV at the EL84's cathode is used as a bias voltage for the heater supply.
The effect is reduced heater hum pickup by the cathodes especially of the preamp tubes.
There's no DC current involved as the heater winding is floating.

[pdf64]

The schematic shows a single pole switch in the neutral side and the mains fuse in the live side, of the mains supply to the PT primary.
What the heck! Is that acceptable in the USA?

[Guitarist1983]

The schematic shows a single pole switch in the neutral side and the mains fuse in the live side, of the mains supply to the PT primary.
What the heck! Is that acceptable in the USA?

I think for modern Fender amps, fuse on live side is common, but power switches usually open both hot and neutral.

[Guitarist1983]

EL84 Biasing question:
I measured Voltage between EL84's pins 7 & 3 (plate & cathode) at 245.7 VDC. The OT primary at 226 ohms, and Voltage across OT primary at 5.64 VDC. So, using a calculator Plate current is 5.64/226 = 25 mA and Plate dissipation is 245.7 VDC * 25 mA = 6.14 watts. If I'm correct, the EL84 is idling at ~50% maximum, right? If so, can I fiddle with the Cathode resistor to increase the plate dissipation?

Beginner question: Why are single tube (6V6 or EL84) amps (e.g., Fender Champ) typically rated at 5 watts output if the tube can safely operate at double that wattage?

[Helmholtz]

EL84 Biasing question:
I measured Voltage between EL84's pins 7 & 3 (plate & cathode) at 245.7 VDC. The OT primary at 226 ohms, and Voltage across OT primary at 5.64 VDC. So, using a calculator Plate current is 5.64/226 = 25 mA and Plate dissipation is 245.7 VDC * 25 mA = 6.14 watts. If I'm correct, the EL84 is idling at ~50% maximum, right? If so, can I fiddle with the Cathode resistor to increase the plate dissipation?

Beginner question: Why are single tube (6V6 or EL84) amps (e.g., Fender Champ) typically rated at 5 watts output if the tube can safely operate at double that wattage?

1) The EL84 datasheet recommends a 135R cathode resistor for class A operation resulting in a plate current of 48mA.

2) Seems you're mixing up plate dissipation and output power:
Plate dissipation is the power that heats up the plate. Output power is delivered to the load. The sum of both is the power delivered by the power supply
A SE class A stage with an EL84 can be biased for 100% corresponding to 12W plate dissipation at idle. With signal the consumed 12W are shared between the tube and the load.
At full power the efficiency of a class A stage is 50%, meaning that 6W are delivered to the load and the other 6W heat up the plate.