DIY 5 Watt SE Guitar amp kit

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I built a really nice sounding SE EL84 amp a few weeks ago into a combo cabinet. The kit was just $215 from MODkitsdiy.com, I got it from Amplifiedparts.com. This does not include the speaker.

It comes with a 10 x 6 x 2 grey painted chassis so I put it in a Hammond 1444-18 (13.5 x 5 x 2) style chassis so I could mount it in my existing cabinet.

Here's my build and review link with video clip.
Kit Review: MOD 102 DIY Guitar Amplifier Kit | GuitarKitBuilder.com


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I put a Plexiglass back panel on to make the insides viewable and safe.
This amp makes a great teaching aid because being point to point, it relates easily to the schematic.

102T.jpg
 
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At the risk of being sexist, I'm presuming you're a woman, I can't imagine a man cutting a heart in the back of a guitar amplifier :D

All well and good, we need more women in Electronics (and in music).

The heart is in memory of my Wife who died of cancer after 31 years of marriage. All of my cabinets now have the heart.

Thanks for asking.
 
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It sounds very good, how did you record it? Also, the schematic is WEIRD.
Uncommon plate and screen voltages and the heater wiring...first time I see that scheme. Hmmm....only 5.5 volts on the cathode. Not much clean headroom. Strange. I was expecting to see the typical Champ schematic....but nope. Well, it seems the el84 sounds better with lower voltages than typical on the plate and screen. Interesting.

The third method is called "DC elevation" and the MOD 102 uses a variation on it by connecting one side of the heater winding to the cathode of the V2 power tube, which is biased to about 5.5 Volts DC. This floats the 6.3 volt AC heater voltage on all three tube filaments (two in the dual 12AX7 and one in the EL84) on top of the 5.5 volts DC. This approach minimizes the hum induced from the heater to the cathode because the induced current becomes close to a constant value when the voltage is above a threshold. In other words, although there is still leakage current, it is constant and therefore the noise voltage appearing at the cathode becomes DC, which is inaudible
 
It sounds very good, how did you record it? Also, the schematic is WEIRD.
Uncommon plate and screen voltages and the heater wiring...first time I see that scheme. Hmmm....only 5.5 volts on the cathode. Not much clean headroom. Strange. I was expecting to see the typical Champ schematic....but nope. Well, it seems the el84 sounds better with lower voltages than typical on the plate and screen. Interesting.

It was just an inexpensive video recorder outdoors.

A lot of people have pointed out the "odd" or "quirky" things in several of their schematics. But this amp kicks butt even though many don't think I am geting much over 3w instead of MODs advertized 5w.

It has a Black Face T&B circuit and an EL 84 output it is no Champ. I have scratch built several Champs and Princetons and none ever sounded as good as this amp does. This amp gets a great natural overdrive tone when pushed.


Thanks for asking.
 
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Joined 2004
many don't think I am geting much over 3w instead of MODs advertized 5w.

Count me in with those that say so.

it is no Champ

No, it's not. It's a Champ with mods and a different output tube. :) IMO, it still has a similar kind of tone.

This amp gets a great natural overdrive tone when pushed.

So does the Champ. You say this one sounds better. Maybe.... it really sounds very good. Can't say if it's because of the speaker, the OPT, or the slightly different schematic. A sum of those probably.
 
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