[hopat]

Hello Everyone,

I finally had a chance to try a RAM amp (the RM 9 MKII with 6550WE output tubes) with my Vandersteen 3A Sig. speakers and the combination blew me away.  The problem is that the dealer said retubing the amp would cost about $800.  The amp looks like it will need tubes soon, and I can't afford the base price of the amp ($2200) along with an $800 retube in the near future.  There seem to be two solutions to this problem and I hoped you might help me choose the best one.  The first is to purchase a similarly priced RM-200 MKI since I could afford to buy RAM tube replacements for this amp.  The second would be to buy the RM 9 MKII, and if the tubes go in the next year, I could replace them with non-RAM certified output tubes.  I assume that both of these solutions would fail to get me the sound I am hearing now, but I imagine they would be close approximations to it.  Can anyone describe the sonic differences between the RM 9 MKII and the RM 200 MKI?  Would using non-RAM 6550WE's risk harming the amplifier?  Which options would you guys recommend?  Thanks for the advice!

[Ericus Rex]

Hello and Welcome to AC!

I own the RM-9 Mk I.  I've never owned the RM-200 but have heard it a few times in shops.  Keep in mind my impressions were never with the same speakers/electronics/rooms/CDs so these generalizations may be way off.

The RM-9 has more of that classic tube sound;  full bass, rich mids, sweet highs but not super punchy in the bass.

The RM-200 is much more of a 'fast' amp with strong punchy bass, still has good midrange but seems to be a bit more extended in the highs than the 9.

They both sound great!  But if your tastes lean more toward SS designs or your speakers need a commanding amp for bass response then the 200 is for you (retubing is much cheaper too!).  If you want a more lush, classic tube sound and your speakers could use a fuller (vs. tighter) bass then get the RM-9.  I'm NOT saying the RM-200 sounds like SS!!!!  It does have that SS kind of speed and command though.

As for tubes, Roger's are definitely best but you can go with other sources if money's tight.  The EL34s are much cheaper than 6550s too.  In addition, with the RM-9, you can run the amp without harm using only half of the power tubes.  Roger talks about this in a thread here on AC.  As for 6550, few people seem to use that tube in audio these days.  Seems to be better suited to guitar amps.  I'd stick with EL34, KT66 or KT88 for audio.

[Gvt1911]

I have owned all of the above mentioned amps and I must say that the RM9 mkII is by far the best amp! I used Svetlana EL34 winged C tubes and never had a problem. I also used vintage T-S 6550's which gave more of an impact. Ended up leaving the Svet's in there. At todays prices, it would be about 300.00 for the 8 Winged C's and I would go with NOS 6922's on the front driver tubes and maybe Tesla 6922's on the back tubes. Should be about $500.00 for a complete retube. Well worth it. On a real MKII there is no "gain" switch by the 6DJ8's and each output tube is fused. Great amp, sorry it is gone. Just do yourself a favor and check the solder joints on the 9 pin driver tube sockets. Sometimes they do develope hairline cracks and just need to be touched with an iron and some solder.
Just my 2 cents!

[Ericus Rex]

BTW, I've been watching the sales of used MR products on the various sites for the past few years and it seems that $2,200 for a 9 Mk II is above the current going rate.  They usually sell for $1,800-1,900.  Add to that the fact that this one may need a new tube set and $2,200 is way overpriced in today's market.  $2,200 for a 200 is a good deal.

[rbwalt]

if it was up to me i would go with some NOS Siemens EL34's and i nice matched pair of V1 tubes. V2 are not critical in the RM9's but you can't switch them. get the tubes from roger. i had a set  of well matched 34's from roger and they lasted 11 yrs!!! by the way the EL34's Siemens is roger's favorite for that amp and mine to. i have NOS Siemens 34's in my RM9SE and they are great!! the choice is up to you but ask roger for his input( you won't go wrong or get a bum answer).

rob.

[rbwalt]

the reason the RM200 came into being was that people were trying to drive speakers with the Rm9's that had a low impedance( Thiel's Maggies, etc.). that ate tubes up. so roger came up with 200 which can drive these with ease. the 200's put out more power as the impedance drops. My SE does the same.  i would say they are close sonically.

[rbwalt]

here is the skinny on 6550's.

more powerful and extended bass
slightly closed in, smallish mids
slightly fuzzy highs

EL34's are better overall except for the bass.

rob.

[hopat]

Thanks for all of the quick and very informative posts.  I saw that Rob mentioned the RM200 was designed because the RM9 kept burning thru tubes with low impedance.  My speakers are 6 ohms nominal with a 4 ohm minimum (87 dB sensitivity).  How much might this impact the predicted life of my tubes in an RM9 setup?  I really appreciate all the help.  Whatever I buy will be my first tube amp, and at this price it will have to last me for the better part of a decade.  So I really appreciate the advice.

[Ericus Rex]

Should be no problem with your speakers.  The RM-9 has a 4 ohm tap as well as 8 ohm.  i think what can be problematic is when speaker impedance drops below 4 ohms at the lower end of frequency range.  That's when tubes can get stressed.

[rbwalt]

i would call roger and ask him about tube life of the 2 amps you are thinking of getting. if you have never chatted with roger then you will be in for a treat!! so you know roger's stuff very seldom breaks. what ever amp you decide on send it to roger for him to give it a good going over! i have had 2 tube amps in my life and both have been music reference.

check out my system so you can see what my amp is driving. it is under rbwalt in the systems section.

let us know how you are making out. glad to help.

rob.

[hopat]

Thanks for the advice guys.  I decided to go with the RM-9 MKII in the end.  I'm very pleased with the sound.  As long as the tubes hold out for a bit I should be good.

Thanks again.

[rbwalt]

hopat you made a good choice. the mk2 will last you many yrs. as far as tubes go if you need any you might try the chineese el34's that roger sells. they are good for the money. what ever you do get matched tubes and get them from roger. i will not buy tubes from anyone else. i think i might have mentioned here earlier that i had some NOS El34's Siemens in my mk2 and i got them from roger and they lasted 11 yrs! i have the same tube in my RM9SE now. i hope this has helped you out.

rob.

[pubul57]

For my taste, within 5 minutes of comparing the RM9 Special Edition to the RM200 it was no contest, and the owner of the RM200 knew it - for our taste the RM9 was simply the superior amp, of course the Special Edition listed for $10,000, but I think the real difference was our immediate preference for EL34 compared to KT88.