6V6 line preamp

[stajo]

It can surely have helped. Isolating vibrations can be counted but its very hard so I usually do trial/error. With bad luck you can enhance microphony if you happen to pick the self frequency regarding to weight and isolation material.

 

[Salas]

Mesh construction breaks resonance. That is why they made such plates on best DHT power valves versions. Just tap on a window mesh frame. Mute thump-thump.

 

[vgeorge]

Ok, here are the latest findings.
Shaking or taping the box, doesn' t change a thing.
I replaced the choke in one channel with 2X11k resistors in parallel the square wave is perfect.
I am listening what the experts have to say now!
Should I remove the chokes?

 

[Salas]

Its the choke then, what else. Chokes have habits it proves. Stajo, go knock at Lundahl's door next time you are about, and tell them "I got a friend with a wiggle, have you got a remedy?".

 

[Salas]

Listen to both R Load and Choke load. The <1kHz sq wave wiggle may prove an insignificant thing when the loading does many other very important things.

 

[vgeorge]

Its the choke then, what else. Chokes have habits it proves. Stajo, go knock at Lundhal's door next time you are about, and tell them "I got a friend with a wiggle, have you got a remedy?".

This is nothing compared to LL1660 measured response....

 

[vgeorge]

Listen to both R Load and Choke load. The <1kHz sq wave wiggle may prove an insignificant thing when the loading does many other very important things.

Will do some tests and see then. Easy to try.

 

[stajo]

Its the choke then, what else. Chokes have habits it proves. Stajo, go knock at Lundahl's door next time you are about, and tell them "I got a friend with a wiggle, have you got a remedy?".

I can do the underpants grip on him next time, Im about to rip him off some 50 mA 1668s sooner or later. Hey, try some pF-nF caps mr Poros, you might find the resonance.

 

[vgeorge]

Ok, will try that too.

 

[stajo]

Found the bestards. Heres what you should use.

 

[Salas]

Now I will ask big favor. We as audience die to see 1kHz square through the 6V6 pre WITHOUT a wiggle in a photo! For the revenge of it!

 

[iko]

Found the bestards. Heres what you should use.

Nice stash! I was looking for one these big ones last year to build a tube AM radio... gave up. Hehe!

 

[iko]

Now I will ask big favor. We as audience die to see 1kHz square through the 6V6 pre WITHOUT a wiggle in a photo! For the revenge of it!

+1

 

[stajo]

Nice stash!

Ive got this crazy friend, from my birth neigbourhood, living in an old country grocery store. His hobby is to build and repair old tube pinball machines. He also has 16 000 tube radios. Most of them from 30s and 40s.

 

[vgeorge]

Ok, here you are.
BW more that 300kHz with resistor load.

 

[vgeorge]

Ooups, wrong picture for the 500Hz, was from yesterday.
If you can edit pls delete. Never mind, fixed it.

 

[Salas]

Left photo Right photo the..wiigglle...bliah

P.S. Good you deleted the sinister thingy that still crops up even in photo scums it stages.

 

[Salas]

300kHZ!!!!!!!!!! How high goes your #26?

 

[iko]

I think my 26 will hide in shame!

 

[vgeorge]

Iko, try a square with a #26 with transformer out.....not good!
Anyway, did a draft listen to it, and I think I go with resistor load. Less prone to microphony and sound is almost the same. There was an impression of more resolution with the choke, but I think it was more from the feedback of the tube and choke. With the choke, you could speak next to the tube and hear yourself through the speakers.
Also more space in the box to arrange things better!