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What Rectifier Tube Does Your Tube Use?


Wolfbane
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How much of a difference do different types make?  (I'm presuming they do make a difference)

 

In my rather revealing Yamamoto A08-S I found a noticeable difference between the EML-80 tube and a NOS 80 globe tube.

 

This is the only amp I did hear an improvement when changing the rectifier tube. Usually I upgrade the small pre-amp and signal tubes first and the power tubes second.

 

Wb

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How much of a difference do different types make?  (I'm presuming they do make a difference)

 

 

Well if you are concerned with the audible difference the biggest will be caused by the internal plate resistance (rp). In a class AB amp there can be large current differences between quiescent state and full signal state, this change in current causes a change in voltage across the rp and the result is audible in the form of compression, or "sag".  The less this resistance the stiffer the supply is. Changing a rectifier out with more or less rp will give you more or less sag. 

 

In a class A amp like the Yamamoto A08-S the current draw is relatively the same from quiescent state to full signal state so there is little change in voltage across the rp. BUT when you change from one type rectifier to another with more or less rp you will get more or less quiescent voltage, this can result in more or less power available since a lower plate voltage means less of a voltage swing.

 

There are a lot of other things to consider from an engineering standpoint when choosing a rectifier but I won't get into that unless anyone really wants.

 

 

-Cindy

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Let's see if we can drop this down (about 4,000 levels) to my level!

 

I have two identical amps.

 

For the sake of comparison, let's presume they are able to use different rectifiers.

 

Amp 'A' has rectifier "W" in it.....and amp 'B' has rectifier "J" in it.

 

Would there be (could there be) obvious differences in the sound or is most of the difference electronic and you'd need a scope to detect it?

 

What if you swap a SS rectifier for a tube?

 

If changing a rectifier does color the sound.....how does that relate to swapping the output tubes?

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Amp 'A' has rectifier "W" in it.....and amp 'B' has rectifier "J" in it. Would there be (could there be) obvious differences in the sound or is most of the difference electronic and you'd need a scope to detect it?

 

 

Are amps 'A' and 'B' the same? If yes running different rectifiers could yield audible differences depending on the topology of said amplifiers. If the amps are not the same it's like comparing apples to oranges. 

 

What if you swap a SS rectifier for a tube?

 

Depending on the topology of the amp you could hear a difference.

 

 

If changing a rectifier does color the sound.....how does that relate to swapping the output tubes?

 

Power tubes in a common cathode configuration with the output taken from the plate takes a small change in voltage at it's grid and creates a change in current at the plate, this change in current across the plate load (Rp) creates a larger voltage swing. All tubes manufactured slightly differ, even in the same production facility, these small differences can be audible due to the amplification nature of the device. A rectifier has zero amplification of signal, it's only job is to pass current in one direction and that's it. It does this by physics, the electrons boiled off the cathode can only flow in one direction, to the positively charged plate.

 

 

-Cindy

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Kindly sent to me as a gift by no other than "xxJPMxx". Pretty swell falla IMO :emotion-21:

 

I know others on here had "issues" with him, but I never had any issues and always welcomed his "side" to things, if even to get people thinking. I can honestly say I only had good interactions with him and welcomed his input, if even to stir the pot a little. I know the amp he worked on upgrading for me sounded much better than before I sent it to him. This was right around the same time Matt was looking to get an amp and we were discussing things.

 

I also paid next to nothing for the rewiring of the circuit, switching from ultralinear to triode mode, upgrading resistors and caps, and even upgrading my rectifier tube.

 

I don't know of any other builders on here who would have charged like he did. I also know none of the other builders on here even replied when I asked if anyone wanted to take on the task of the upgrade. 

Edited by Jim
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Howdy,

 

I like the following (in no particular order); UX-4 Socket: Type 80, and 83 Mercury Vapor... UX-5 Socket: Type 84....Octal Socket: 5y3g, 274b, 5R4GY, 5U4g and 5U4GB... Noval Socket: 6CA4/EZ81 and lastly Small 7-Pin Socket: 6X4. All of these have their uses, and are typically selected based on the current/voltage drop requirements of the circuit in question. Additionally, heater-voltage tap availability (on the selected power transformer and/or the need to add additional transformers) also plays into the selection process. Ultimately, the selection is based on achieving the necessary performance of the power supply as a whole. Just my thoughts....

 

TS Matt.

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Kindly sent to me as a gift by no other than "xxJPMxx". Pretty swell falla IMO :emotion-21:

 

I know others on here had "issues" with him, but I never had any issues and always welcomed his "side" to things, if even to get people thinking. I can honestly say I only had good interactions with him and welcomed his input, if even to stir the pot a little. I know the amp he worked on upgrading for me sounded much better than before I sent it to him. This was right around the same time Matt was looking to get an amp and we were discussing things.

 

I also paid next to nothing for the rewiring of the circuit, switching from ultralinear to triode mode, upgrading resistors and caps, and even upgrading my rectifier tube.

 

I don't know of any other builders on here who would have charged like he did. I also know none of the other builders on here even replied when I asked if anyone wanted to take on the task of the upgrade. 

 

 

 

I read your little adventure and I think its great that you got a helping hand...but realize your amp was not working right when it went to the tech... a bad rectifier tube alone can just flat out run the sound of an amplifier. 

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