A couple of new amps - not 100% finished but making sound

[RetiredUnit1]

i initially grabbed a small cheap oscilloscope (DSO112A) to do exactly this on previous amp builds.

not sure if it's user error, shitty device, or otherwise, but sometimes it's really hard to tell a difference in 'noise' between the x2 ends.
i've mostly done this with radial orange drop caps - maybe they're less susceptible to this noise / shielding phenomena - where traditional axials appear be more prone to it?

Did you use a noisy device? Those spiral neon bulbs are VERY noisy, so are most 120v outlets and even switches. I have an EMR detector and was shocked to see outlets put out more noise than wifi.

I have tested orange drops before, with my handy dandy polarity reversing audio tester. Turn that amp UP so it really amplifies the sound and I think you'll notice. You have to move the bulb till it's right next to the cap to generate a "test" signal.

 

[HamishR]

Well even with my computers on, the amp open and my office fridge right next to it I'm not getting any buzzing from the amp so I'm probably ok!

I'll probably make one of those testers though.

 

[TheHammer1982]

I've been thinking about building an amp for a long time now but I can never decided on what to go with.

 

[RetiredUnit1]

I've been thinking about building an amp for a long time now but I can never decided on what to go with.

It doesn't matter because it's like pedals, once you build one you can't wait to do the next!!!

 

[TheHammer1982]

It doesn't matter because it's like pedals, once you build one you can't wait to do the next!!!

Building and storing 30 pedals is significantly cheaper/easier than building and storing 30 amps lol.

 

[music6000]

And here is a 6G3 Brown Deluxe I also built recently. I was inspired to build this after playing a Suhr Hombre in a store recently. It's a great sounding amp. I had built a 6G3 a few years ago but I swear this one sounds better. I'm not sure what I did differently.

Probably the way you drilled & screwed the missing holes in the Chassis!

 

[owlexifry]

Did you use a noisy device? Those spiral neon bulbs are VERY noisy, so are most 120v outlets and even switches. I have an EMR detector and was shocked to see outlets put out more noise than wifi.

I have tested orange drops before, with my handy dandy polarity reversing audio tester. Turn that amp UP so it really amplifies the sound and I think you'll notice. You have to move the bulb till it's right next to the cap to generate a "test" signal.

actually, you know what has made a way bigger difference than worrying about outer foil ends on film caps?

ground schemes.

a while ago i did a build of one of robrobinettes wiring layouts (40W SLO), i had very little idea what i was doing, and followed it blindly (with a few tweaks), and it all worked well.
it had a single grounding point at the input.
it was ok, but i didn't realise there were a number of undesirable ground routes that didn't really follow ideal returns to filter cap nodes etc.

eventually i got a clue about grounding, studied that grounding chapter by merlin blencowe, and with those principles in mind - did a complete revision of the ground scheme and made a shitload of changes.

holy crap, it was night and day.
not only did it become dead silent, but the response felt like the amp was running more efficiently and had this punchier response to it. definitely worthwhile.

 

[RetiredUnit1]

actually, you know what has made a way bigger difference than worrying about outer foil ends on film caps?

ground schemes.

a while ago i did a build of one of robrobinettes wiring layouts (40W SLO), i had very little idea what i was doing, and followed it blindly (with a few tweaks), and it all worked well.
it had a single grounding point at the input.
it was ok, but i didn't realise there were a number of undesirable ground routes that didn't really follow ideal returns to filter cap nodes etc.

eventually i got a clue about grounding, studied that grounding chapter by merlin blencowe, and with those principles in mind - did a complete revision of the ground scheme and made a shitload of changes.

holy crap, it was night and day.
not only did it become dead silent, but the response felt like the amp was running more efficiently and had this punchier response to it. definitely worthwhile.

I found this out the hard way on my first amp, a 5e3. BUZZZZZZZ GRIIIIIIIIINNNNDDDDD HUMMMMMM

My first and only kit came with the instructions for a star ground. But what it didn't have was the ORDER you put the different grounds on the star. I had done the power caps and output transformer on last, with the preamp on first, thereby guaranteeing a noisy build.

On the axiom that current always takes the shortest route to ground, I put the power caps down first, then the output transformer, then the preamp (which is multiple grounds including the preamp power cap). DEAD SILENT!

One nut, lift three wires, put them back down. Talk about easy fix!!!

 

[Cvoxdog]

I lucked out on a great jtm45 clone for a steal of a price and it's one of my favorite amps. It just rips.