DIY Low wattage tube amp?

[tw0409]

Been thinking about building a tube amp for practice session. I currently have a 25 watt 6L6 powered amp, which is too loud when I need to crank up to get some good tone.

I am looking at the MOD 102 DIY tube amp kit. a 5 watter and it fits the bill nicely. My only problem is that it only has treble, bass and volume control.

Is it possible to install a master volume to the circuit?

Thanks guys!

[pdf64]

Yes but there would be little benefit, as there's insufficient pre amp gain to get much overdrive.
5 watts through a proper guitar speaker is still freakin loud in a domestic situation.
See http://amptone.com/#lowwattamps to get an understanding of the issues.
Pete.

[5992]

This one is half a watt:

http://www.gerhartamps.com/gilmorejr/gilmorejr.htm

http://www.gerhartamps.com/gilmorejr...rejr_order.htm

[tw0409]

I was just checking out the Gilmore Jr. Looks real nice I would say, but it's way over my budget.

Are there other DIY kits less than 5 watt and $300?

[HawkeyeKane]

Not under $300, but a solid 2 watt amp is the Mojo Bedroom amp.

http://www.mojotone.com/amp-parts/am...om-Amp-MBA-Kit

[mchap11]

Originally Posted by tw0409

I was just checking out the Gilmore Jr. Looks real nice I would say, but it's way over my budget.

Are there other DIY kits less than 5 watt and $300?

I lucked into a 1/2 watt Gilmore Jr. kit a guy won in a raffle and got it for very little money. I'd never really soldered before--built it anyway and got the two-watt accessory tube-thing. It's become my favorite recording amp (home stuff). I've paired it with an old Bell & Howell 12" (16 ohm) in a crappy pine cab I built and I guess they'll wind up burying it with me when the time comes.

The folks at Guytronixs talked me through every idiotic issue I had (being a newbie amp builder) and answered all of my questions. They were always extremely polite, prompt with a reply, and they knew I got this second hand. You don't even need to know how to read a schematic--the wiring diagram makes it crystal clear. I cannot recommend a company more. Save up! Buy one!!

[WaltC]

Rich at Guytronix is a truly nice guy and the Gilmore Jr. is great sounding little amp and can drive anything from a 1x8 cab to a 4x12 cab.

Disclaimer:
I re-worked John King's Gilmore Jr. manual to produce the Ardmore assembly manual for Rich and Gary.

[tw0409]

Nice to know that guys!

Before I settle on Gilmore Jr, I want to ask...Is there an amp or a schematic like this:

-EL84 power amp
-Has master volume
-Less than 5 watts

Thanks!

[oldhousescott]

Here's a thread from the Hoffman amp forum containing several low-watt schematics. I built the Little Wing (changing the preamp to a JCM800 style) and it sounds great.

[tw0409]

Originally Posted by oldhousescott

Here's a thread from the Hoffman amp forum containing several low-watt schematics. I built the Little Wing (changing the preamp to a JCM800 style) and it sounds great.

Looks interesting. How does the over driven sound of little wing compare with EL84 amp?

Also, how do you change the preamp to a JCM800 style? do you have the schematics?

[oldhousescott]

8 watts is still plenty loud and has plenty of overdrive, but it doesn't have the punch of a higher wattage amp.

Regarding the preamp, I separated the paralleled first tube into cascading sections. I used 2.7k/10uF on the cathode of the first stage followed by the volume control. I used 5.6k/.68uF on the second stage cathode into a 470k/470k voltage divider with a 470pF across the upper 470k feeding into the third stage. I used 100k plate resistors for both stages. Coupling caps were 22nF IIRC.

[pdf64]

-EL84 power amp
-Has master volume
-Less than 5 watts

It's unusual for a power tube to be used in an amp designed to have a power output much below the tube's potential.
Things would have to be changed so much that they wouldn't be regular guitar amp designs anymore, eg the B+ voltages may need to be less than 250V, high OT primary impedance.
So EL84 don't tend to be used in amps much under 4 watts.

Why do you think you need a master volume?
The ethos of these low power amps is that power amp overdrive can be achieved at more reasonable sound pressure levels.
It's beneficial to have plenty of gain on tap, in order to achieve a good level of overdrive / sustain, but that's a different design goal than a master volume is usually specified for.
Pete.

[torquil]

Originally Posted by pdf64

The ethos of these low power amps is that power amp overdrive can be achieved at more reasonable sound pressure levels.

5W is easily enough for hearing damage, so I don't find the volume of a cranked 5W amp to be reasonable.

[pdf64]

Yes, absolutely, apologies.
In my defence I put 'more reasonable', and the focus of the thread had shifted towards very low power amps, ie the Gilmore Jnr at 1/2 watt.
And in post #2 I did indicate that 5 watts (cranked) was excessive for domestic use.
But agreed, hearing loss needs to kept at a high profile as being a major issue for rock etc musicians, as youngsters are so often incredulous that it will ever be a problem for them.
See http://en.wikipedia.org/wiki/Exposure_action_value for further info.

If you're lookin spending a few hundred $, then consider getting a Fluxtone speaker http://www.fluxtone-speakers.com/ for your existing amp.
It's been a massive benefit for me, in being able to achieve a great, consistent tone even down to very low sound pressure levels.
Pete.

[tw0409]

Thanks for the info guys!

I found this and it seems perfect for me! Tell me what you think.

http://www.ampmaker.com/store/SE-5a-...amplifier.html