Metropoulos Forum

Aloha from Hawaii,

I am about to embark on building the JTM45 kit. I’ve done many amp mods before that turned out great, but never an amp from scratch. There so much great information on this site, and my hope in writing this is to see if I can get some help distilling it down to the best approach to get a very good amp that may not be perfect, but could be upgraded if I decide to. I can only imagine that the JTM45 kit will easily rival something I can buy off the shelf from Marshall, and I hope the advice that I get here will make that a reality.

Here are some initial questions that I have:
1) transformers: the ones through metro or MMs? The MMs are almost double the price, but I can’t imagine that you see double the performance. Is there a compelling reason to take a look at the MMs if I’m not looking to eek out the last 1% increase in performance/sound?

2) upgrading caps and resistors from what’s in the kit. Worth it or not? Again, 1% increase in performance to me is not worth it, but you guys are the experts.

3) Master Volume. I installed a MV on my fender hotrod deluxe and it was a fantastic addition. I typically play with the clean channel at 3 o’clock and use an overdrive to push it into breakup, and the master at noon, so I’m not afraid to play loud, but it’s also nice to dial it down to keep my wife from smacking me. My intent with the 45 is play it loud, certainly not bedroom volumes, but it would be nice to tame it when needed (which is a small part of the time). So, worth it or not?

4) effects loop. I don’t use one now, but I don’t need to with my Fender or Orange, and I don’t use a lot - just a liitle delay, reverb, and univibe here and there. Maybe Marshall designs perform better with the time based effects in the loop. I guess it’s probably just a personal preference, but I’m asking anyway.

5) tubes: any particular combinations that people have had good experiences with? What does George use in his commercial amps? Are tubes the tubes on the 45 kit page good?

6) are there any other obvious mods to consider? If the kit will get me to great Marshall JTM45 tone without doing anything else, that’s good enough for me. I’m more of a purist than someone who needs lost of options.

Thanks in advance for your time and advice. I really appreciate it.

Mike from Hawaii

Welcome to the forum! You didn't mention what kit you were looking at but if I may make a suggestion...be sure to check out...http://valvestorm.com/JTM45%20Kit... When Metroamp stop selling kits years back, Valvestorm kinda took over the products. You can purchase the barebones kit which has great components, or you can opt to pick and choose your own parts from their inventory. You will also find that the Metroamp instructions which are linked at the very top of the page in purple, will work perfectly with the turret board and chassis they sell. The transformers are up to you. The Metro transformers are very nice as are http://marstran.com/ which are both manufactured by Heyboer to their own individual specs. The Classictone line...http://www.classictone.net/Marshall-Sty ... rmers.html are also excellent alternatives but in the end the choice is up to you. I have used them all and they are all top notch.

I like to implement a ppimv in these amps to knock off just a touch of volume. If you try to use too much, they start to effect the sound negatively imo. If you are looking to install an effects loop, the Metro loop works very well and installs easily.

Thanks Danman,

Yes, I’m going to build the valvestorm kit. I started out looking at all the 18watters and reminded myself that I would like at least a little headroom, so I decided the JTM was the best fit for what I play. I think what you are saying is that the basic kit is great, any one the transformer sets are great, and the ppimv is a welcome mod.

Thanks for the advice,
Mike

Many folks decide to install the Metro loop in these amps but many classic records were recorded back in the day with all effects going into the front end. The loop can be installed later if you decide that you do need it. Please post some pics when you start the build.