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What are you building?

sonar

sonar

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Jan 10, 2003
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maxwedge said:
+2!


Looks much better!:salude
The only thing I see is that line voltage twisted with the filament wires. Untwist it and just run it on the chassis next to the transformer up to the power switch.
Click to expand...

Line voltage done.

So I'm getting some intermittent static that kicks in and out on low bass notes. I originally thought it was the filter caps, but that doesn't seem to be the case. When I put some pressure on the circuit board (with a chopstick) it mostly goes away. I really don't want to get into shock mounting the board or pull out the glue gun so I'm going to try and reflow some of the wiring around the PI, which I think might be the trouble area. My theory is the vibrations are effecting a cold solder(s)?
 
M

maxwedge

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Apr 6, 2010
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With me and strange noises like that I always go after tubes 1st and then poke the chop stick on the tube sockets checking for possible loose pins. I suppose it could be a cold solder joint if you're not sure that you soldered hot enough.
 
sonar

sonar

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Hey Scott,

I am getting a little tube rattle off I think the rectifier (the power section in this amp has been a pain in the...) but the socket connections on the power tubes seem to pass the chopstick test. I did reflow/redo the solder on V1, which cured about 90% of the problem until I put the back panel back on the amp. I'm suspicious of the two 100K resistors and their jumper wire, but getting under the circuit board is a project.

My window for cranking this amp up to where the static kicks in is limited. It could be sometime next week before I get the chance to crank it up.

Oh and by the way the amp sounds glorious with a P90 - very Live at Leeds. Lowering the cap values and the G12H30 also makes the Bright Channel very humbucker friendly at the expense of some of the original circuit's character. I'll take the tradeoff.

I
 
M

maxwedge

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Are you sure it's not the back panel it's self. It's very common for tweed style cabinets to buzz ect and is one of the big reasons Fender and all the others went to the 60's style. The trick is to get the chassis adjusted just right to put pressure on the back panel to reduce noises. Some manufactures used screws in to the chassis, like my old Ampeg.
 
sonar

sonar

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The amp's static was there with the panel off. I think adding the panel (and the additional vibrations caused by it) also effects the noise. That said, I need to rethink how I'm going to add pressure between the back panel and the chassis.
 
sonar

sonar

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And where are all the builders?

A year later and both the Princeton Reverb and 5E3 are seeing use, with the PR being my main band amp.

People are not kidding about the tight quarters and sensitivity to noise in the 5E3 Chassis. One wonky little solder (on a resistor) was the cause of all my static headaches. Fortunately the amp has become hum-free and seriously kicks some butt in the land of overdrive. Lesson one on that build - The erasure end of a Ticonderoga #2 is an invaluable diagnostic tool.

I'm thinking the PR probably needs a fresh set of power tubes. The JJ's have performed quite well over the past 2 years, but they were pretty mismatched from the start (so much for purchasing a matched set) and have become noisy with the bass loosing definition over the last couple months. I'm kind of hesitant on burning up a set of NOS in a clone, so thinking maybe new again? The RI Tung Sol's have been whisper quiet in the 5E3, but I've read some have issues with the TS's and higher voltages with the BF amps. Any recommendations?
 
B

B Ingram

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Jan 3, 2016
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sonar said:
New build - 6G15.
Click to expand...

Nice!

Maybe a bit too late, but I greatly prefer the 6-spring tank with medium decay for this circuit; 9AB2C__ (spaces left for locking pan & mounting direction). I find it allows a very natural and full sounding reverb where the dwell can be turned up without getting unusably-cavernous (but then again I don't play surf music and despite my love for Fender reverb amps, I always seem to have way more reverb than I need).
 
B

B Ingram

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Jan 3, 2016
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My latest build: 2 channel 1/3 watt amp, currently in the assess/tweak stage.

The channels are a 6AK5 pentode channel with volume & gain controls, and a 2x 6BC4 triode channel with Treble/Middle/Bass tone stack and gain/bass-adjusting mini switches. There is an output stage power control which allows reduction of output power of the 6AU6 (really just for late night apartment use).

Knobs and faceplate won't be added until I'm done evaluating/tweaking, as there's no guarantee every control/switch will make the cut for the final version.

Chassis%20Front%20Resize.jpg


Chassis%20Inside%202%20Resize.jpg



"What the hell are 6AK5, 6BC4, 6AU6? Why would you use that garbage in an amp?"

All 3 are small-signal tubes which have been used in wide-band, specialized audio or radio circuits, but aren't commonly used in hi-fi (though the 6AK5 is starting to be bid up by Little Dot owners). Despite what you see for these on some tube vendor sites, they are easy to find for less than $2/ea, and all are old production. And I happen to already have a bunch of them on hand (enough to be several-lifetimes' use for me), so I figured I might as well build something with them.

The parallel turret strips flank either side of the tube sockets, in a build style inspired by old Tektronix tube scopes. Heater wiring actually runs socket-to-socket over/across the sockets and underneath the parts mounted on the turrets. For some, this looks like it should induce hum, but the heaters are always 90-degrees to signal-carrying parts & wiring, and in practice is very quiet.
 
B

B Ingram

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Last edited:
Tridyed

Tridyed

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Jan 10, 2016
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More of a re-build thing here. My old Vai Legacy 1 has been making a bit of crackling lately so I am going through the whole amp and re-capping the power section and I am going to replace all the tone stack with orange drop caps. I am also going to put in switchcraft input and output jacks and I have a new set of tubes to add at the end as well. This amp is just a great sounding head and I can't wait to get it done and start playing it again.
 
sonar

sonar

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Had a 4 month break due to life interfering.

Anyway, got back to it last night. Finished populating the board and mounted everything.

Tonight I'll start wiring.
 
Dreadnaught

Dreadnaught

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Feb 26, 2004
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Not really a build, but I bought a tattoo jvm 215 50 watt last year that I was underwhelmed by. This year I retubed with genalex el34 and matched 12ax7 (new) and tossed in a Celestion Gold for the G12b. I left off the back cabinet. The difference is night and day!
 
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