Forgive me TubeLab ... I have sinned

[rkevans]

It has been 6 months since my last confession.

In that time, I have committed numerous transgressions involving a Simple SE circuit board.

1. I have not built a proper chassis for the amplifier.

In February, I upgraded the enclosure from a surplus Ikea wooden shelf to a smaller 'custom' kludge. It was constructed in 40 minutes with a stack of slightly warped 18mm plywood, a table saw and a nailgun. The wood is unfinished and the entire thing is ugly.

My only concession to elegance is the usage of the 'approved' discount-store cd-rack, flipped upside down and attached to the chassis as a metal tube cage.

2. I have sacrificed numerous slow-blow fuses while performing unintentional quality-control tests with rectifier tubes.

I'm using an IEC-style 'RFI-filtered' power receptacle, and it requires 2 of the amusingly obscure 5x20 fuses -- and both of them fail when I do something stupid like try using a JJ 5AR4.

When the fuses fail, I end up visiting Radio Shack and actually have a request that the employees can handle. They are able to find the drawer with fuses and if I speak slowly and clearly, they can identify a 2A slow-blow package. It is not nearly as much fun as making a request for obscure items such as "a 10k resistor" or the seemingly mythical "op-amp" which stumps them 2 out of 3 times.

3. I often use the amplifier with a variety of truly craptastic speakers.

It has driven $9 car-audio coaxials during initial testing. As I type this, it is playing through 20-year-old Infinity 'studio monitors' purchased from a base exchange on a since-closed AFB in California. Infinity 'enthusiasts' universally treat this model as a curse word and I cannot disagree -- they do everything poorly.

For two magical weeks, it was connected to a pair of lovingly handcrafted Half Chang speakers with Fostex -206E full-range drivers (look in the 'full range forums' for details). Then I decided to actually stain/finish the HC pair and... uh... they're still in the workshop, unconnected to anything.

4. I have used the amplifier to torment various UOS (used old stock) tubes.

It's currently abusing a mismatched pair (KenRad and National Union) of metal-case 6L6 output tubes (way too much voltage, a couple watts of 'extra' plate dissipation) with a 5Z4 rectifier (rated for 350 VDC and 125 mA, running way beyond that). They're probably screaming in pain, but with the metal cases, it's hard to tell.

5. I have ignored most of the optional configurations available.

The amp has spent less than 5 minutes in pure triode mode, then I tried ultra-linear and never looked back. It has never used cathode feedback. I've removed the solid-state diodes from the board and may never install replacements.

6. I have forced it to play non-audiophile music.

This morning, I used the poor amp to play an entire country CD. I do not even own "Jazz at the Pawnshop".

Sometimes I get a little drunk and threaten to buy a polka album. When I sober up, I ask forgiveness and offer to play that Cowboy Junkies disc that it likes so much.

-=-=-=-=-=-=-

Rick

[n_maher]

This thread is pure win.

[tubelab.com]

They're probably screaming in pain, but with the metal cases, it's hard to tell.

When the silver (or white) paint starts to turn brown you are getting close to the edge, when the black paint peels off, you have crossed the line. Back in high school I won a bet with the teacher that I couldn't make the metal envelope glow red. After blowing up several NIB RCA 6L6's (our class had hundreds of them) I discovered the technique.

I used the poor amp to play an entire country CD.

OK, if you promise not to tell anyone, I will admit to feeding mine some John Anderson. Only once though.

[Curly Woods]

Originally posted by tubelab.com


OK, if you promise not to tell anyone, I will admit to feeding mine some John Anderson. Only once though.

A little "Just a Swingin" :-)

[Geek]

Originally posted by n_maher
This thread is pure win.

Amen

[chrish]

I know the temptation! My "cure" is to build the chassis first

[Ty_Bower]

Originally posted by rkevans
1. I have not built a proper chassis for the amplifier.

Pine framing lumber, baby. The only way to go.

[Brit01]

Pine framing lumber, baby. The only way to go.

Sounds like a good plan to me.

I've built an Aikido, headphone WCF, and a couple of CF buffers without any chassis yet.

I'm always to eager to start the next design without making a house for the first project.

[whitelabrat]

I've played some Lawrence Welk on mine. Not proud of that, but I did it.

[ethermion]

Originally posted by rkevans
It has been 6 months since my last confession.

<snip>
Sometimes I get a little drunk and threaten to buy a polka album.

Rick

So, what's wrong with polka? It's just Polish Bluegrass.

Get yourself a Frankie Yankovic CD. Get drunk and play Too Fat Polka over and over. Or try my favorite Just Because.

In triode mode with your full range drivers, you will hear the mechanical clatter of the accordion keys as if he were there in the room with you. Spooky.