Im open to it.
Draw it up. Explain to "the class" why its advantageous.
Also, why UF4007?
1N4007 vrs. UF4007 fast diode
Last edited:
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Let's build a tube preamp
- Thread starter rufus.K
- Start date
-
- Tags
- build preamp tube tube preamp
Draw it up. Explain to "the class" why its advantageous.
Also, why UF4007?
1N4007 vrs. UF4007 fast diode
Once I get home, sure! Maybe sooner if the actual class I'm actually going to is boring.
Figured you'd catch me in between two computers with LTSPICE on them…
Im assuming we will be using bridge rectifier layouts (not full wave) for all this. I will explain it in a bit (unless someone does it first) when I get back.
Im excited to learn from you all, as well as drawing new people into this who may be curious but daunted.
Im excited to learn from you all, as well as drawing new people into this who may be curious but daunted.
Also, on every tube amp schematic I have, the power switch is before the transformer. I think this is to prevent the PT from being unloaded.
Technically, it's the square root of 2, but what are a few decimal places between friends
Obviously diode rectification is going to be the way to go for simplicity and cost, but I was thinking about it the other day and I don't know that I've ever actually played a tube rectified amp, so I'm curious about it.
Maybe you could build the rectifier on a modular sub-assembly and try both so we can compare the end result.
Or build both and make it switchable, a la the Heritage B-15
Maybe you could build the rectifier on a modular sub-assembly and try both so we can compare the end result.
Or build both and make it switchable, a la the Heritage B-15
Ive only used dropping resistors so I dont know. We're gonna have way more power with this tranny than we need, I dont mind blowing it off as heat if its too much.
I know there are more elegant ways to do things. one con of dropping voltage via resistors is that it wastes power.
Doesnt full wave provide .9?
Passinwind
I know nothing.
- Dec 3, 2003
- 23,087
- 46,069
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
I'm pretty slammed right now with my own DIY work (at least 5 new PCB designs in progress at the moment), so I'll most likely be watching more than posting, but here's a good tool for working on the power supply design: PSUD2
So, 12ax7 tubes need a voltage source for their "heaters" that is different from the other voltage source that drive the plate. The plate (anode) is where the power to amplify goes in, and the voltage amplified signal comes out (if we're using it as a voltage amplifier ). This is called the B+ voltage. It's a long story, don't ask why.
The voltage on the plate is DC. The voltage on the heater can be either AC or DC. The power coming out of the transformer's secondary windings are AC. we'should still talking about how we're going to do our heaters, but we can talk about making DC from AC. it's done through a circuit called a rectifier. They can be bought pre made, but we are going to make our own because they're simple.
In essence, all you need is a few diodes. The specific diodes doesn't matter at this moment in discussion. Basically, they allow current to flow in 1 direction by clipping off one half of an AC waveform. If arranged correctly, one can harness both halves of an AC wave and double them back on themselves to make a single direct current instead of an alternating one. This arrangement is called a rectifier.
The voltage on the plate is DC. The voltage on the heater can be either AC or DC. The power coming out of the transformer's secondary windings are AC. we'should still talking about how we're going to do our heaters, but we can talk about making DC from AC. it's done through a circuit called a rectifier. They can be bought pre made, but we are going to make our own because they're simple.
In essence, all you need is a few diodes. The specific diodes doesn't matter at this moment in discussion. Basically, they allow current to flow in 1 direction by clipping off one half of an AC waveform. If arranged correctly, one can harness both halves of an AC wave and double them back on themselves to make a single direct current instead of an alternating one. This arrangement is called a rectifier.
