Metropoulos Forum

Ok guys, I am looking at doing some work here on my 50watt. I need to know some things.

1.) Caps! I have all SoZo Next Gen caps. I am finding that after playing them a year they have smoothed out almost too much. The amp is not as aggressive. I have heard amps that a friend built with Mallory's that are more aggressive and alive. The SoZo are super warm and flub the bass a bit. What do you guys like for Caps? Mallory? SoZo? What works for that aggressive Brown Sound?

2.) My amp is a bit different due to the fact that when Dave Friedman modded my amp, I had an OUTPUT TRANNY blow. He had a Hammond OT laying around that he put in the amp to replace the blown OT. Well guess what; my buddy who worked on my amp found out its a JTM45 OT.. by Hammond. So we left it in there. What do you guys think about that? I am at the understanding that a JTM45 OT will work just fine. Dave Friedman put it in there; so I am assuming he knew what he was doing with it? Educate me on this! Because its been on my mind for a while! Am I worried about nothing?

3.) Preamp tubes! What does everyone like? What works? Tried some Mullards and they blew out in the first day. Lemons much! Had an original Sylvania 12AX7 that went bad... today. So I have to questionable chinese 12AX7s in there. Any thoughts?

Again, this is a 50watt Plexi. Wanting to get the most out of it.

This is what I've found,

1) For the most part, the signal cap brand/material can only make a subtle difference, with the cathode bypass spots being the most obvious (the VALUE of the cap is most significant). I'd suggest using polypropylene there for what you have said your looking for (aggressive).

2) The actual brand/type of transformers are probably MORE responsible, at the end of the day, for your amp being 'smoother' sounding than others ? That ot you said was in it would be the MAIN culprit imo. I'd get a MM ot, I've heard they have a bit more stiffer and aggressive feel as compared to others.

3) I'd say just try some current tubes that are from a reputable dealer

This is really too difficult to address. We need a baseline to work off of in order to be of any help so you should really arm this thread with clips and pics. For example, when you say too smooth, or not aggressive enough. Does this mean too much high end rolloff? Or does this mean the amp is clean and not enough distortion? Or maybe it's all to tight and compressed like a Rockman. Nothing gets specific like good ole clips pics.

jnew wrote:This is really too difficult to address. We need a baseline to work off of in order to be of any help so you should really arm this thread with clips and pics. For example, when you say too smooth, or not aggressive enough. Does this mean too much high end rolloff? Or does this mean the amp is clean and not enough distortion? Or maybe it's all to tight and compressed like a Rockman. Nothing gets specific like good ole clips pics.

LOL Been a busy weekend. I will get pics to you when I can.

My buddy is going to do some work on this for me. I think swapping the caps out and the bright cap, plus tubes will all help. I think just minor things.

My other amp; 2203, is already off to my friend. These SoZo's are really making the low mids pop out. He has found that the Mallory's make his amps more alive. He sent me some clip of his personal amps that he has tweaked and there are differences in the tone between the Sozo and Mallory. Mallory is more alive and in your face. Thats basically what I am wanting. And he uses new tubes. I have old Sylvanias. And I have to wonder if those are starting to take a dump. Might swap them for some EH. Not sure yet. One amp at a time! LOL

The mallory's are far from a mustard cap sound. Very far. I did extensive tests between real mustards and the next gen and mustards in a vintage plexi 100 watt with real deal iron. The verdict was the next gens were almost dead nuts on, they were slightly brighter though. With breaking in they would be identical.. So I would look at tubes or other things first.

RACKSYSTEMS wrote:The mallory's are far from a mustard cap sound. Very far. I did extensive tests between real mustards and the next gen and mustards in a vintage plexi 100 watt with real deal iron. The verdict was the next gens were almost dead nuts on, they were slightly brighter though. With breaking in they would be identical.. So I would look at tubes or other things first.

Ok, I will play around with the tubes first. Maybe check the bias, etc. I still have old Sylvania 6CA7s in there... that you installed. I bet the tubes are just getting old.

My question is how do we really know how a mustard cap sounds when they have been sitting around drying out for 40 years? Is there really any true gauge? Even if they are NOS, they still have been sitting around exposed to oxygen for 40 years. Even if Sozo were to replicate the Mustard Cap... are they replicating the "sitting around for 40 years" dried out mustard?

Otherwise, I am going to check the tubes and bias. I have not rebiased the amp in years. I just left the tubes where they were. Might even try some EH 6CA7s. I hear people are having luck with them. I would like to get away from unreliable OLD parts.

One other thing to look into is modifying the presence circuit. I think I put a 50k pot in my plexi instead of the stock 25k, just so I could dial in more high end bite and sizzle. It's kind of like the 50k Mid pot, just gives you some more flexibility in dialing in the sound in your head.

Try switching to chick let .68 instead of mustards,makes the amp Little more aggressive and tad brighter

bmf5150 wrote:Try switching to chick let .68 instead of mustards,makes the amp Little more aggressive and tad brighter

That will be one of the experiments that my amp guy is going to try out for me. Thanks man!

Yeah, I think we have this nailed down on what we are going to do. Should be easy to get this thing where I want it. Just small tweaks!