[qguy]

Hi i have an opportunity to purchase an RM-9 and would like to know if anyone has a softcopy of the manual and Review in Stereophile - thanks

Any comments from users of RM-9 ?

The one that is for sale has EI L34 tubes installed, i have read that the RM-9 can work with a variety of tubes (6550, KT88, KT90 etc) , is this true for all versions ?

Thanks

[Ericus Rex]

Hello,

I've been a guest reader for some time now and just registered to reply to your post.

I own the RM-9 (original, not MK II) and it's the finest amp I've ever had in my system.  Rich and spacious describe its sound best.  I have only heard it with EL34 tubes but yes, it can run 6550, KT88, KT77 and possibly 6L6 (not positive about the last one - some can without mods, some can't).  Most EL34 amps can run the other 3 types.  I have had the following amps in my system.  Most are gone, a couple listed I still own just so you know what the RM-9 has gone up against:  Counterpoint SA-100, Audire Crescendo and Tenendo, Quicksilver Silver 60  and GLA  and 8417 monos, Pass Aleph 0s.....there are more but my mind has gone blank....oh well, you get the picture.  The RM-9 is the most expensive of all of these, perhaps something much more expensive might be better.  Or you could look at it as being the best amp at this price level (my choice!).  Most of my other components I can see exchanging in the future for something else but right now I  can't see ever getting rid of this amp (or my Counterpoint SA-5.1....or my....or my....).

As for biasing, you must use matched quads, there are no individual tube adjustments (the MK II does allow ind. biasing of tubes).  You basically push a button, look at the red led and turn the screw with a precision screwdriver until the left and right leds match intensity.  I biased mine when I got it three years ago and haven't touched it since.  It's that stable...though maybe tonight I'll check up on it....been a while I see....

Hope this helps!

[Scottdazzle]

I have an original RM-9, too.  It's as wonderful as Ericus Rex says it is.  Roger Modjeski provides copies of the manual, schematic, reviews, and other documents to owners upon request. He charges $25 which I thought was excessive until it arrived.  He personally prints or copies the documents and binds them for you. You can contact him at his Audio Circle forum.

[GHM]

I owned a MK2 version of this unit...sounded phenomenal ! I would love to own another. Sold the other one off several years back. Some of the fellows selling these used, have fallen and bumped their heads! Asking prices are much too high in some cases.  Maybe one day I'll get another..it will be here as long as I am.

Good luck to you

[Roger A. Modjeski]

Hi,

I have several RM-9 and 9 MK II available factory re-conditioned with custom mods available. They range in price from $2000-$3,900 depending on condition. The collector's edition manual is available at http://www.tubeaudiostore.com/manuals.html.

The manual is not necessary for one with a bit of tube knowledge as everything on the amp, including adjustments, is on the amp itself. I did this because manuals and their amps are soon parted.

The rear LED is for bias, the front LED and push-button are for driver balance. They are independent adjustments.

We offer matched output quads and selected for balance driver tubes at very reasonable prices. I have just finished helping a RM-9 owner deal with two sets of supposedly matched tubes he got from other sources. They were not well matched and, even worse, several had excessive grid leakage which caused fuses to blow repeatedly.

As far as I can tell, RAM LABS is the only tube vendor matching at constant current rather than applied grid voltage.

[Scottdazzle]

Roger,

As far as I can tell I have an early production RM-9 that has never been modified. It works perfectly and I am quite happy with it, but I would be interested in improving its performance if there are any mods that you recommend for early models.  Are there any?

Scott

[Roger A. Modjeski]

As many of you know, I make changes only when there is something that will provide a significant improvement in performance. The RM-9 MK II incorporates a major change in the power supply with the addition of a choke and final filter for each channel. Channel interaction and 120 Hz modulation are both reduced to vanishing small levels. The other change was to help users identify bad tubes in the unit itself without the need for a tube tester. That involved the installation of 8 fuses, one per tube. I also added one LED per fuse to indicate a fuse out. Otherwise one would be endlessly checking the fuses. I make great effort in my designs to make them user friendly. The MK II also has solid copper binding posts that are scaled to handle today's heavy cables.

The upgrades start at $750 for the power supply mod to $1200 for everything. All mods include our $400 "go over" where we replace anything that needs replacing to bring the amp up to spec.

[Samh]

Hi Roger,

I am the happy owner of an RM-9 Mk ll.  Are there any suggested mods?  I currently have EL-34s installed.  How would the sound change if I changed to KT-88s?

Thank you,
Mas

[IkeH]

I have RM-9 (original) since the late 80's.  Over the years, I've tried different types and brands of tubes.  As I upgraded various parts of the system (i.e. cables, speakers, digital front end, analogue front end..), I eventually came back to using EL-34s.   From the current production EL-34s, I felt SEDs and JJs work well.  However, I have not tried the new Mullard branded Russian tubes yet.   

As to KT-88 (I've only tried JJs and Chinese ones) , in general, in my experience, it would tend to sound more punchy and bit bright (depending on your speakers it may give you added bass and sense of air)  Personally, this was not my cup of tea.

6550s (I've only tried GEs),  was my favorite until I changed my speakers.  Very natural soudning mids and highs but can be a bit boomy.  With small monitor type speakers, it may give desired boost in low frequency therefore can be a good match.  If you have a full range speakers it may give you too much bass.