[TomekZ]

I recently purchased, second hand, an Ultra 4a SE with the PS1t.

I love this preamp very much, both for it's looks, but especially for its sound. During the past couple of months I've had a AVA Transcendence 6 and an Audible Ilusions 3 preamp. The Maple tree Ultra 4a surpasses both. Compared to the Audible Illusions 3, it has more clarity and openness; the detail seems spacially more correct, that is the ambience of a concert hall seems right; the Audible Illusions, though, has more control when there is an orchestral crescendo. Compared to the AVA Transcendence 6, there is simply more richness to the sound.

I've tried some Hitachi 12sn7gt tubes and some RCA 12sx7tubes. The RCA tubes are sweeter and sound a few rows further back in a halll by comparison. This matches better with the rest of my system which consists of Jordan jx92s drivers in a transmission line and a Gainclone amp.

I wonder how the sound would change if the 6sn7gt tubes were used in the line stage? I ask this as a general question, and more specifically in regard to the new stock Electro Harmonix 6sn7gt?

~Tom

[DavidS]

Tom

Not much discussion happening regarding Mapletree products.  Don't think I can help re tube rolling with the MAD preamp - I was hoping to see some discussion regarding your question for my own interest.

I too have a second hand MAD preamp - mine is a Line 2A SE that I acquired this summer.  Have been very impressed with how it has smoothed out my sound while giving me more detail than previous integrated amp set up.

Mine has Rogers 12SN7GTA tubes in preamp with I think a Sylvania 6X5GT on the power supply.  Have no idea even what else to try and what I could expect from different tubes.  Tubes seem as complex as French red wines...not sure how much I want to go there.

Only negative for me with preamp is how small and light it is.  Gets bounced around by stiff power cord I use (a Venhaus cord) and even slight tugs on interconnects.  Would love to be able to do some comparisons to other preamps I read about on this site and elsewhere and understand how good it is in my system.

David Speed

[DavidS]

Just a quick report to say I finally got the courage up to try some different tubes in my Mapletree.  Not sure what I have been waiting for - dramatic improvement in both dynamics and detail - one of those changes that you can't stop grinning about.

So what I did is swapped my rogers sn7's for some Hitachi 1960's black plate  sn7's .  Might still have to try some 12xs7's as suggested by Tom to compare as well.

Think I now have the courage up to try replacing the rectifier tube.  Currently have stock sylvania 6x5 which I understand can be replaced by something like a Bendix or Tungsol 5852 to good results.  Will try and acquire one of these and see what happens.  

David

[Hollow Fate]

I purchased an Ultra 4A SE with PS 1t power supply directly from Lloyd a few months ago and tried various tube pairs to improve the already super sound.  The biggest disappointment was a pair of NOS JAN Sylvania 6SN7WGTA’s that weren’t cheap that I’ll be Ebaying off to a new home.  I did hit pay dirt however with a pair of vintage 1954 NOS JAN RCA 12SX7’s I got from a fellow in Holland who had them priced like 12SN7’s.  Shazam.  All the propaganda about these tubes (at least in this particular circuit) is true.  Wider soundstage, better delineation of instruments, richer and deeper bass, vocals that “talk” to you.  I drive a solid state NAD power amp from the Ultra 4A and still the quality of Lloyd’s design and the 12SX7’s come through.  All my 6SN7’s are now redundant.  I should add at this point that my speakers are KEF Q5's and they are of super quality to my ears.  Another pair of 12SX7’s I picked up from the Dutchman were vintage 1955 Rogers (made in Canada) JAN 12SX7’s.  On some night’s listening I give the Rogers the edge on the RCA’s, but it’s a very tight race.  The fellow in question has no more of these tubes left.  I bought all ten.  Ebay prices tend to the Nuts side of things on these tubes but there is a tube seller in the States who has a swag of GE 12SX7’s ex-Canadian military (although they are not listed as JAN tubes) for US$12 each, listed as used-like new.  Cheapest price for 12SX7’s I’ve seen.  I’ve no idea how they sound though. If interested send a post for more info.

I have used interchangeably  6X5, 6X5G, 6X5GT, and a Bendix 5839 rectifier tube.  The Bendix is a 25-volt unit.  I had Lloyd build in a separate filament transformer and switch into the PS1t power supply for me.  Mainly I wanted a piece of tube history (Bendix – Red Bank Division) glowing in my pre.  The bottom line for me however is that sonic improvement does not lie in different rectifier tubes.  Try elsewhere.  Oh well, ‘twas worth a try.  (The Bendix remains in place just the same.)

If you use the 4A for vinyl listening swapping out the 12SC7’s and subbing Russian 6N2P-EV’s can give a big improvement.  My particular 6N2P-EV’s are out of the “Voskhok” tube works in Kaluga, Russia and are probably vintage early 1970’s.  They are identified by a neat-o logo of a missile “zooming” horizontally.  If you go looking for Russian tubes try for those with the “–EV” extension after the tube number.  This means the tube is long-life and “rugged built”.  Also, any Russian tube with the “OTK” designation stamped on it means it was individually hand tested to military standards and passed with flying Soviet colours.  The improvement with these tubes inserted into the 4A is like night and day.  The 6N2P-EV’s are 9 pin miniature tubes similar electronically to the 12AX7’s and easily got off Ebay.  I had a hunch about this tube after reading up on them and built an adapter to try them out and the results are a stunning improvement to any LP you play.  Because the stock 12SC7 is really a 12SL7 with cathodes common you need to connect the two cathodes of the 6N2P-EV to mimic the 12SC7.  Best to have the good Dr. Lloyd set this one up as the possibility of smoke is only a single solder mistake away.  

Well that’s it for my opinions.  Best of luck and good listening.

Hollow Fate
(Donald Glynn)