24V guitar amp

[El Heisenberg]

Well the bridge rectifier thing was a stupid bad idea. I was getting 24v on the 12k5 heaters and only 1 more volt at B+.

hey, it might just be my imagination, but the thing sounds louder with the 12AE7s heaters on 6 volts ac. Is it cos the power section is getting more juice?

Also can't you use a lower output tap since it's two in parallel? so if it were 800 ohms, you could use 400 ohms? I already switched to my 500 ohm tap and it sounds alrite.  



Guess i'll start thinkin of how to record this

[iccaros]

I would not go lower than 500 ohms..

I need to see how your heaters are wired.. Mine are like the diagram. 24v accross both is 12 over each

[El Heisenberg]

Im using a 24v 2A CT transformer. 12.6 on each lead. I wired the heaters using the center tap and the ground. So im only using 12v heh.

[El Heisenberg]

I swear the thing is louder with a 22 ohm 5 watt resistor dropping the 12ae7 heaters down to 6v ac. I switched back to the way it qas wired originally and it sounded quieter. So i went back to 6v. Tell me im wrong. Cos it sounds dumb.

Anyway i wired my heaters in parallel i guess. I thought the diff between paralell and series were if you used the 9th pin or not. My ct and ground lead go to pins 3 an 4 of one 12k5. Then those pins go to the same pin 3 and 4 of 12k5 2 and also to pins 4 and 5. So it all measures 12.6. I didnt know this was incorrect.

[iccaros]

There are two heaters in each 12ae7 or 12U7 tube. so in series is from pin 4 to pin 5 and parallel is pin 4 and 5 hot with 9 ground.

When I speak of in series I am speaking of from one tube to the next. It is standard to wire each tube on its own or parallel with each other. But I have 4 tubes so I have two groups of types. 2 12k5 and 2 12u7. I wire the 12k5's in series with each other and the 12u7 in series with each other.

12k5
hot ---> pin 3  out pin 4 to pin 4 next tube out pin 3 to ground

12U7
hot ---> pin 4 out pin 5 to pin 5 next tube out pin 4 to ground
Since this is a SE amp wiring out of phase is suppose to help lower noise..

[El Heisenberg]

K we're talking about DC only or both AC and DC? I thought with AC it didn't matter

Thanks for puttin up with my dimness

I Thought i could just use 12v to power all the heaters. Ill have ta re wire them in parallel?


This isn't my pic its the one from the sopht amp site, but besides the extra 12k5, my heaters are wired exactly the same. My power filter section is same to except I use a 22 ohm:

[iccaros]

DC only, AC matters if it is higher than 12 volts.. You can elevate your AC heater with a DC voltage, but the heaters do not care AC or DC and will see the higher voltage. I know elevation works to keep with in spec, but I am not sure how.

In any case if you have two tubes connected in series over 24  volts you do not need the resistor.
The single preamp tube will need it.

if they are each connect to hot and ground on their own, then they each need the resistor. @ 24 volts

[El Heisenberg]

Ah im using AC power. So everythings fine. I added the line out too. Just need the jensen speaker and itll be done.

[iccaros]

Ah im using AC power. So everythings fine. I added the line out too. Just need the jensen speaker and itll be done.

I may test mine this weekend at a Gig.. See how well mic'ing it up works and how it will do..

[El Heisenberg]

http://dl.dropbox.com/u/4685682/loop%2012k5%20amp.mp3

[El Heisenberg]

sorry so crappy (recording and playing) recorded with the muti-track iphone app. I just set it on top of the amp.

chain is Jazzmaster, OCD, OCD, Fat Boost, SHecho, Mobius Trip, 12K5 amp.

[iccaros]

tone sounds good, has a doors feel..