RM20 vs RM50 with mods

ricky · Dec 26, 2014

I have both the RM20 and RM50. What are the main differences in them besides the wattage and tubes? I have a stock RM50 and a JF modded one, both with 6L6's. Certain mods just don't sound right with the RM50s and the 6L6's. I will then put them in the RM20 and the difference is apparant. Will changing one of the RM50 6L6 tubes for the EL34s make as much of a difference as the EL84s in the RM20?
I had Rob voice the modded RM50 as a fender-ish sound and it is stunning with the modded deluxe, tweed or VybeDeluxe. I am just wondering about "marshall-ing" out my other RM50.
as an aside, I also own an RM4 and use it stereo with a Carvin TS100 using 6L6's and it doesn't seem to matter as all of the mods sound great in there.
I am really curious about this as I have always palyed Fender amps and this is new to me.
thanks
rw

Mattfig · Dec 27, 2014

ricky said:
I have both the RM20 and RM50. What are the main differences in them besides the wattage and tubes? I have a stock RM50 and a JF modded one, both with 6L6's. Certain mods just don't sound right with the RM50s and the 6L6's. I will then put them in the RM20 and the difference is apparant. Will changing one of the RM50 6L6 tubes for the EL34s make as much of a difference as the EL84s in the RM20?
I had Rob voice the modded RM50 as a fender-ish sound and it is stunning with the modded deluxe, tweed or VybeDeluxe. I am just wondering about "marshall-ing" out my other RM50.
as an aside, I also own an RM4 and use it stereo with a Carvin TS100 using 6L6's and it doesn't seem to matter as all of the mods sound great in there.
I am really curious about this as I have always palyed Fender amps and this is new to me.
thanks
rw

I think you might just dig smaller glass...That's cool....You may dig KT77s in your RM50...You could also get Yellow Jacket converters and run EL84s in your RM50...

As for the TS100, I have one too and think it sounds phenomenal with every mod! I use a mix of EL34 and 6L6 in mine and just love it...I think the TS100 could be one of the best power amp pairings with MTS...

JKD · Dec 27, 2014

KT-77 is my favorite all round big tube....and I love the YJ in my RM50 too....

I've had a couple pairs of EL84s not last long though.....maybe due to high voltage or maybe one of my YJ is not working right.

Jaded Faith · Dec 27, 2014

It's not a tube thing, it's the differences in the power supplies making up the lions share of the differences. There is far less B+ in your RM20, there is no choke, the transformers are GROSSLY under spec and they have different supply filtering. There are also differences in signal flow. Putting EL84's in an RM50 won't change any of these factors.

These topics are also most of the answer to the questions people have regarding comparing MTS amps to other "real deal" amplifiers. Tuning preamp modules can only do so much. You have to look at the entire equation. The MTS amps have a very "safe" middle-of-the-road tuning to the amps themselves.

ricky · Dec 27, 2014

So what causes the Fender style mods to sing and the marshall style mods to be "blatty" in the RM50 and not the RM4 or RM20?
The RM4 is my gold standard for any mod as they all sound great in there. I was assuming that it must be b/c of the TS100 amp but am still not sure. Will my modded RM50 be able to be voiced more for the Marshall mods?
And for Matt Figg: You are right about that Carvin TS100. Running anything into it with the 6L6s and in stereo is quite an auditory experience. I am really wanting my RM50s to be that same thing as much as possible.

Jaded Faith · Dec 29, 2014

ricky said:
So what causes the Fender style mods to sing and the marshall style mods to be "blatty" in the RM50 and not the RM4 or RM20?
The RM4 is my gold standard for any mod as they all sound great in there. I was assuming that it must be b/c of the TS100 amp but am still not sure. Will my modded RM50 be able to be voiced more for the Marshall mods?

I'm a little puzzled by the term "blatty" and not sure what that really describes. What I can do is provide a list of variables between your RM50's and the baseline RM4:

- different B+ voltages
- the RM50 power supply also needs to feed a PI and power tubes
- the RM4 has an additional buffer tube stage to push the output through your cabling and to better drive your power amp
- the design/type of PI circuit
- the design of the power amp circuit and values used in it
- the amount of negative feedback used in the power amp
- the speaker and cabinet being used with the amp (not only the speaker, but the dimensions of the enclosure and type)

This is no small list and the last two items are huge. I can't emphasize that enough.

Hopefully this list help provide some food for thought.

Mike361 · Jan 1, 2015

I can't see why you wouldn't, 34's are fairly cheap for 2 tubes. Try them or even kt66 tubes sound great in some marshals. I have el34's in my combo and 6l6's in the head both rm50's. They do sound different , both running the same cab. I will say I was surprised the 6l6 tubes sound good even with the marshall modules. But you get more midrange chunk using 34's.