Metropoulos Forum

I had a short time to make these clips, so I just used the Doug Rappaport DI track again. Original Superlead #12380 and Metropoulos replica #12092. The owner recently bought NOS Mullards for the entire amp, so I tested and installed them.

I didn't edit or compress the clips in any way, here's what I recorded in Reaper:

https://dl.dropbox.com/u/64682773/12092 ... 202013.wav" onclick="window.open(this.href);return false;

https://dl.dropbox.com/u/64682773/12380 ... 202013.wav" onclick="window.open(this.href);return false;


Like in the signal cap clips thread, it's best is you put these files into a multi-track audio software and switch between them on the fly. Or better yet, have someone else switch and try to guess which is which!

Settings on both amps were:

into Volume I top input.

Vol 10

Treble 6

Middle 10

Bass 10

Presence 6

Metropoulos in variac mode, original variac'ed to approx 95V AC. Through Hot Plate at -8db. Randall iso cab with ASW KTS-70. Beyer M160 > Hamptone FET mic pre. RME multiface > Reaper.

I found them to be shockingly close, those NOS tubes really put it over the edge. The replica is stock 12 series specs with a mix of Sozo and Mallory caps.


george

It may be something here but I can't hear anything...

12092 is louder, brighter, a bit dirtier, with more edge compared to 12380. It would be interesting to see pictures of the two amps to compare circuitry which might explain the differences in tone.

Tazin wrote:12092 is louder, brighter, a bit dirtier, with more edge compared to 12380. It would be interesting to see pictures of the two amps to compare circuitry which might explain the differences in tone.

That is exactly how my 68 SL sounded when back to back with a 12 series that I did for a forum member a couple of years ago. The original had smidge more gain and maybe a bit more in the way of complex harmonics. I plan to do the same again with another 68 and a Metro 12 series before too long.

Here's another comparison, this time a video posted on youtube.

[youtube]http://www.youtube.com/watch?v=-Uh2I_z3MVE[/youtube]

The NOS mustard caps definitely narrow the gap, the replica responds just like the original and cleans up well. The full Mullard compliment in the original seems to retain a touch more definition and sparkle. 80% of the audio is from the iso cab (off camera). I think it does a better job illustrating the slight differences than I could hear as I played. There was no audible difference in the extreme high frequencies, possibly due to my old work out H's in the slant cab.

The recent clips really shine a light on the importance of the amp switcher. I've gotten far closer to the mark since I started using it.

It would be interesting to hear the amps compared using the same set of old tubes. But I think the little tweaks I made to compensate for modern tubes and parts would be counterproductive with NOS tubes. I'll try to get to that before the amp ships off to it's new home.

george

Sounds very close George, but remember the Metro amp haves nos Mustards not even broken in. I think with time the amp will sound same as the og.

Kinda wierd but in the video the chords sound louder on 12380. Also at times chords played on 12380 sound a tad less bright and a bit mid scooped depending on which strings are involved with the chord. Single string stuff doesn't seem to highlight the differences mentioned above with exception of the percussive low E palm mute stuff.

Agreed! I'm finding that different chords, playing styles, places on thr neck, single notes, muted playing etc all can sound different......or sound just the same. It's a strange phenomenon. I tend to think the old amp, with vintage tubes and parts (including original filter caps) has an interesting complexity and almost randomness. The replica sounds and feels more consistent.

I'll burn the new amp in over the weekend and listen to how it opens up. Maybe swap the old tubes in and listen too.


As encoraging as it is to feel like I'm getting close, the real trick will be to get here without using NOS parts and tubes. To build something with new parts that sounds vintage, that will be a challenge!


George

neikeel wrote:

Tazin wrote:12092 is louder, brighter, a bit dirtier, with more edge compared to 12380. It would be interesting to see pictures of the two amps to compare circuitry which might explain the differences in tone.

That is exactly how my 68 SL sounded when back to back with a 12 series that I did for a forum member a couple of years ago. The original had smidge more gain and maybe a bit more in the way of complex harmonics. I plan to do the same again with another 68 and a Metro 12 series before too long.

Very cool. I find that replicas tend to have more lows and low mids. Plugging actual part values measured on my original into the Duncan tone stack calculator confirmed where some of those frequencies were going. It also helped me tweak the replica to match the frequency response.

George

George, does 12380 have a single element Hunts 50uF/500v phase inverter filter cap or the Hunts 50uF + 50uF/450v filter cap? I have to agree with your statement that the replica (12092) sounds more consistent (less randomness based on what strings or chords are played). As for frequency dynamics, it seems like the replica (12092) stays within a locked envelope when performing its tasks whereas 12380 has a "basic working envelope" but is able to step outside of it at times.

You mentioned actual component values in regard to 12380....Have some of the values drifted considerably?

axeman wrote:Sounds very close George, but remember the Metro amp haves nos Mustards not even broken in. I think with time the amp will sound same as the og.

Very true. It was at about one hour total from first start up. So comparing a completely 45 year old amp to one that was literally just born.
It will be cool to hear it settle in.

George

Tazin wrote:George, does 12380 have a single element Hunts 50uF/500v phase inverter filter cap or the Hunts 50uF + 50uF/450v filter cap?

Dual 50uf PI cap.

George

They really are very close - did you have to tweak any values in the clone to get them the same (or is that a trade secret?)?

The tighter bottom end is presumably down to newer filter caps (or athey the same in both?).

George, any luck on narrowing down what components are causing the randomness in 12380? Also, did your 10series amp (SL/10584) also have this strange phenomenon?

Pic of #12093.


george