Curious phenomenon

[12AX7]

I built a amp that i eventually gave to a friend and built myself a new one. All the same components except his layout was a lot different. I sat down and perfected the layout when i built the second one and it's very different. And the amps sounded quite different. Very similar as far as style of sound, but his sounded much stronger and punchy for lack of a better description. Maybe a good was to put it is more alive and full. Tho mine sounded more refined and controllable from clean to dirty, and he liked that. Anyways, he asked how i could get his to sound like mine and i told him the layout was the only big difference so a new board should do it. And so i did. End result was it still had the same aliveness and all it had over mine before, but now also has the more refined tone. so it sounds a lot better than mine. I want to understand how this could be, but i can't see what could cause this. The trannys and choke are the same too. Same chassis, layout, components, tubes, everything. So the only thing i can figure is trannys. But i have tried different OT and PT in my amp and that made little difference. Has anyone else experienced something like this, and if so did you ever figure it out? The only difference which i can think of is mine has one of those filtered mains socket, but that can't be it, as it did have an unfiltered socket before and i noticed no change when adding the filtered one. I just wonder if theres something i'm not thinking of....any thoughts?

Oh, and voltages are very close everywhere.

[Heinz]

Is it possible that the first amp has less negative feedback than the second one (e.g. by a wiring error, a bad solder joint, a different feedback resistor value, etc.)?

When you say "punchy" and "refined", "no feedback" vs "feedback" comes to my mind immediately.

[tdvt]

Different speakers?

Or just more broken-in? (if they're the same exact thing)

and/or cabinet...

[12AX7]

They both have variable NFB via a 33k resistor in series with a 100k pot. Speaker i tested it with is my amp's speaker. So can't be those. 

[LooseChange]

What's the age difference between them? Is yours new?
Parts burn in time will effect the tone. Most notably... More fat... Fuller sound.

[Dave]

Have you tried transferring the tubes over from the good one to the not-so-good one to see if it is the tubes that are making one sound different than the other?

Dave

[punkykatt]

Did you actually swap the tubes from one amp to the other? Perhaps one or more tubes could be weak?

[punkykatt]

I see Dave beat me to it.

[stingray_65]

It could be nothing at all.

most tube amps sound differnt. There are the exceptional and unique ones. even built by the same mass manufacuturer on the same day with the same tubes, any two should sound different. Lead dress, layout, bias, parts tolerance,tubes, knob settings any could account for the percieved difference, more than likley the sum of all that plus some more mojo thrown in.

You said yourself it has the same voicing, just a different responce.

This is where an amp builders skills REALLY shine, tailoring the amp to get a specific "tone".

IF the amp is within tolerance, AND you know the end "tone" or "feel" or whatever you want, The guys here can help you narrow down what changes you may want to make. It was suggested to look into the NFB circuit. You already have a pot there, have you just set it according to what you did on the last amp? or have you fiddled with it yet?

LOL any how what do I know   I'm dumber than most and brave enough to prove it on a regular basis  

I did notice one thing, you didn't  mention that you didn't like it, that sound OK to me!

Has your friend played it? what's his opinion? I know I grade my projects on a much tougher curve than I do others, I'm a little more sensitive to nuances, more critical to minor things. a second trusted opinion may change your hearing a bit.

Ray