How important are transformers and how (if) do they shape the tone?

[waltschwarzkopf]

Hello, World!

Given my current understanding of electronics, I know that the transformer will take the mains (110V/220V) voltage and change it to power the tubes which could work around 450V and also other components that work at lower voltages like 12V. However, I've sometimes read in forums expresions like "massive" or "oversized" transformers.

This comes to mind, as I am considering buying a Peavey Valve King Rolay 8 in order to mod it and turn it into a head and play it through a 12" Vintage 30 that I have in a box project. I read somewhere that someone changed the transformer for a better sound, maybe even to get more headroom. And this is where my confusion comes from.

I thought that the tubes and circuitry shaped the sound of the amp, and that the transformer only provided the needed current.

Could someone explain this to me?

Also, since I have another donor amp (Marshall Valvestate 8040 40W). Could I take this bigger transformer and use it on the peavey if needed?

Thanks in advance!

Cheers,
Walt

[NegativeEase]

One important point -a larger transformer doesnt mean better tone or really a specific tone influence itself alone. -it's about it's relationship with the speaker impedance and handling, suspension, material (speaker voicing etc) and if how the transformers electrical output qualities are enhancing, neutral, or degrading the the most influential part of your sound -the speakers.

[GuitarStv]

I've often heard people talk about this, but never understood it myself.

[jeremy]

a tube amp has two big transformers, power and output. it might have others (reverb, choke, interstage, etc..) but power and output are the important ones in this case. your valvestate amp isnt a real tube amp so probably only has power transformer but since transistors dont require as much power as tubes, its probably not be suitable for use in even a small single ended tube amp like the peavey.

there is a lot to know. start here for how a tube amp works

https://robrobinette.com/How_Amps_Work.htm

then this explains a bit about output trannys

https://www.mercurymagnetics.com/pre...t-transformer/

the power tranny does take the 120v from the wall and convert it to the different voltages an amp needs. changing the B+ the tubes see can make a big difference in the feel and output of an amp. if a tranny is undersized it can strain under a heavy load and cause sag in the voltage, if it is oversized it should be able to keep up with any load without working hard enough to falter, thus keeping the response of the amp tighter. again, that is a very simple glossing over of the complexity of whats going on

[waltschwarzkopf]

Wow, thank you all for the links and detailed explanations! I really appreciate it.

Unless you know a lot about these things or have someone who can help you figure out what specs you need, the only real assurance you have is that a transformer will generally work with the amp it came in, and nothing more.

I guess this is the take home message, I don’t know a lot about transformers, so I guess I’ll leave the transformer alone for the time being. I’ll focus on other simpler mods that I feel confident with.


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[Toe-Knee]

The biggest factor is more on the output transformer side of things where different transformers can have wildly different frequency ranges.

[Ewizard]

Well, hold on everyone.... The sound of an amp is NOT just about the OT. the PT. does play a rather large role as well. Let's make an example. If you are simply taking the OT. out of an already made and designed amp and swapping in an OT. from a different vendor or perhaps model, it MAY have a difference in sound that is marked or noticeable. That is not to say that it will sound different, or better, or worse. It may, that is all you can be assured of. Now if you design an amp from scratch, you have ZERO basis of what that transformer you picked will sound like unless you try several to see which one suits the amp the most.

The PT. has a pretty big impact on the sound of an amp. How do you ask? It supplies the voltage to all the parts and how it is loaded down will change the voltage to each node of the amplifier's power supply. If you choose an oversized PT for the task, it will be considered stiff and will not be as easily loaded down by the components in the power supply, this will likely result in higher voltages at each node in the PS. Conversely, if you use an undersized or barely adequate PT., it will load down more causing a lower voltage at each node. That change in voltage and the resulting PS sag WILL cause the sound of the amp to be different if all else is the same.

Most people think that it is simply the resistors, capacitors, and the circuit itself that determine the sound of an amp. Take the Fender Bassman and the Marshall JTM-45 for example, they are very similar in many ways. The differences that do exist make for a rather large difference in sound though. However, it is not just the transformers and the circuit changes alone that make up that difference. The speakers are probably the single biggest contributor. The rest is more about flavor and feel.

[waltschwarzkopf]

Well, hold on everyone.... The sound of an amp is NOT just about the OT. the PT. does play a rather large role as well. Let's make an example. If you are simply taking the OT. out of an already made and designed amp and swapping in an OT. from a different vendor or perhaps model, it MAY have a difference in sound that is marked or noticeable. That is not to say that it will sound different, or better, or worse. It may, that is all you can be assured of. Now if you design an amp from scratch, you have ZERO basis of what that transformer you picked will sound like unless you try several to see which one suits the amp the most.

The PT. has a pretty big impact on the sound of an amp. How do you ask? It supplies the voltage to all the parts and how it is loaded down will change the voltage to each node of the amplifier's power supply. If you choose an oversized PT for the task, it will be considered stiff and will not be as easily loaded down by the components in the power supply, this will likely result in higher voltages at each node in the PS. Conversely, if you use an undersized or barely adequate PT., it will load down more causing a lower voltage at each node. That change in voltage and the resulting PS sag WILL cause the sound of the amp to be different if all else is the same.

Most people think that it is simply the resistors, capacitors, and the circuit itself that determine the sound of an amp. Take the Fender Bassman and the Marshall JTM-45 for example, they are very similar in many ways. The differences that do exist make for a rather large difference in sound though. However, it is not just the transformers and the circuit changes alone that make up that difference. The speakers are probably the single biggest contributor. The rest is more about flavor and feel.

That was a great explanation!


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[jeremy]

pretty sure i mentioned something about the pt in my post. totally agree it has a big impact on how an amp performs

[LLL]

Yes.

[NegativeEase]

Well, hold on everyone.... The sound of an amp is NOT just about the OT. the PT. does play a rather large role as well. Let's make an example. If you are simply taking the OT. out of an already made and designed amp and swapping in an OT. from a different vendor or perhaps model, it MAY have a difference in sound that is marked or noticeable. That is not to say that it will sound different, or better, or worse. It may, that is all you can be assured of. Now if you design an amp from scratch, you have ZERO basis of what that transformer you picked will sound like unless you try several to see which one suits the amp the most.

The PT. has a pretty big impact on the sound of an amp. How do you ask? It supplies the voltage to all the parts and how it is loaded down will change the voltage to each node of the amplifier's power supply. If you choose an oversized PT for the task, it will be considered stiff and will not be as easily loaded down by the components in the power supply, this will likely result in higher voltages at each node in the PS. Conversely, if you use an undersized or barely adequate PT., it will load down more causing a lower voltage at each node. That change in voltage and the resulting PS sag WILL cause the sound of the amp to be different if all else is the same.

Most people think that it is simply the resistors, capacitors, and the circuit itself that determine the sound of an amp. Take the Fender Bassman and the Marshall JTM-45 for example, they are very similar in many ways. The differences that do exist make for a rather large difference in sound though. However, it is not just the transformers and the circuit changes alone that make up that difference. The speakers are probably the single biggest contributor. The rest is more about flavor and feel.

My response was to the OT change out, great points on PT...