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Prima Luna Integrated - EL34, KT88, KT150, Brimar AU - My experience

Thought I would help out some who are considering rolling some tubes ......
Prima Luna Dialog Premium HP Integrated Stereo

Stock EL34 - Chinese I think
JJ/Slovakia KT88 - from ARS
Tung Sol KT150  - yep, these are it, and worth it, do it.. purchased matched from Upscale

First, I have to tell you, I LOVE this amp.  Prior to this, I had a pair of monster VTL Deluxe 300 monoblock tube giants.  In short, the VTLs were less veiled... but the PLs are so musical, believe it or not, better bass! yes, true. and way more fun to own given the tube rolling flexibility.  (I only use the amp in ultralinear, higher power mode).  Oh, and the auto biasing feature - no more burnt fingers or back twists!  BTW, VTLs were a pain and flaky - still loved them and owned them for about 15 years.

The PL comes stock with (Chinese I believe) eight EL34 power tubes.  Out of the box, the amp is stellar.  Why did I try rolling tubes?  Well I have a big stock of power tubes left over from my VTLs.... KT88s ... so after a few months of using the amp as stock... I tried the KT88s.  These KT88s are labeled JJ/Slovakia and BTW, Upscale said to me they won't carry these KT88s from JJ because "their quality control is awful".  Anywho, I put them in anyway. 

EL34 = beautiful.... just a wonderfully musical tube - nothing wrong here - PL did a good job choosing this tube
KT88 = more dynamics, a bit more power, better fuller bass, but something was a bit wrong on the top end.... had an odd edge up there.  Overall I am not sure which I liked more.... the EL34s are perfect but I liked the more dynamics and bass of the KT88.. but their top end ... hmmmm..... I would switch them and therefore hear their strength and say "these are better"... then I would switch and say the same thing.  Issue was there were trade offs.
KT150 =  This is the tube you want.  Compared to the EL34... a bit more dynamics, less veiled, much more power, deeper bass.  Sounds very linear top to bottom.   The only negative of the KT150s over the EL34s... I think the EL34s were a tiny bit more musical... but the KT150s are very musical themselves.  Overall, the KT150s are staying put.  Done.
More to the story.... before I purchased the KT150s I traded emails with Upscale... we discussed the JJ KT88s... they suggested swapping out the front two 12AU7 gain tubes with Brimar CV4003 NOS (made in the '60s).  So I did... and I hated them!  OMG.... they did something to the top that made my ears bleed.  I really let them break in but I had to pull them out as I just couldn't take it.  Now this was with my JJ KT88s.  Upscale responded to me and said I was the only one to complain and describe them as bright.  So... I put the amp back to stock.... listened for a few weeks... then I put the Brimars in with the EL34s ... well OK, much better.. but I still am not sold on the Brimars.  I did learn that my KT88s really do have something bad going on at the top end given these Brimars screamed their issue.  So.... let's buy some KT150s from Upscale.

Note: Upscale said that many like their KT88s over the stock EL34s due to the dynamics and bass improvements so apparently, these JJs have a sonic characteristic that is different than other KT88s.  Maybe.  If all KT88s sound the same, then I can't recommend them.  If they don't all sound the same, then I can say strongly, don't bother with the JJ/Slovakia brand.

I have not tried the Brimars with the KT150s.... right now I have no desire to do so the amp sounds so good.  I probably will try them some day... maybe in a few months.
Anywho... I hope this helps some folks. 

PeaceBruce in Philly

bruce_philly
bruce_philly OP
28 posts
 
Oh, a few more items... just cause I can.....
I was so sold on tubes, I purchased the tubed Sonic Frontiers DAC and tubes really smoothed out the digititus of the day. Today, I own a PS Audio DirectStream DAC Junior that I am totally amazed with (no tubes but not digititus).
There are risks associated with tube amps.... this is my experience.... speakers that have difficult loads don’t mate well to tube amps. The PL gets good marks by reviewers for their ability to push difficult loads, but I am cautious about this due to my personal experiences.

I purchased a pair of Martin Logan Quest Zs.... awful with my big VTL monoblocks..... sounded "glassy" (odd, I thought problems would manifest in the bass, but not so) .. the MLs were known to have a difficult load ... I was traveling back then and would stop into ML dealers wherever I was .... always sounded great... always were displayed with transistor amps. The moment I hooked up my MLs, I knew something was just plain wrong. I kept the MLs for maybe 60 days.... shortest time for a component in my life.... I moved back to Magnepan with the MG 20 and they were good with the VTLs. However, these big Magnepans sounded way better in the bass when a friend brought over a CJ transistor amp... so.... tubes can have trouble in the bass.
So.... my rules of thumb for tube power amps: 1) don;t use them with speakers with difficult loads, 2) don;t use them with low efficiency speakers, 3), get a tube amp with higher power over a lower power unit.
There are always exceptions... for example if you don;t listen to rock, you don’t need a higher-power tube amp. If you do, get one with some juice.
Oh, biasing... the PL amps autobias... a godsend... I had to bias, with a multimeter 16 tubes on those VTLs and I grew to hate it. Just hate it. You have to bend over, get your plastic screwdriver into a slot (never would go) and dick with it. I would burn my fingers and you can;t put the amps into a rack, I had to get my head in there. While any amp you buy will most likely be a bit different, don’t assume it is not a big deal... it becomes a pain.
I could go on.... but if you follow my rules of thumb, you will be very happy with tube equipment.
PeaceBruce in Philly
astelmaszek
78 posts
 
I've yet to find a tube that sounds better than NOS amperex/valvo DD getter el34 in a primaluna amp. Bass as good as a kt150 with that lovely el34 midrange bloom. As far as nos go, you can still find a quad under 400 unlike kt88s where genalex now commands 1500+ for a quad.
leotis
151 posts
 
I think the hard edge is in part due to ultralinear mode. Try triode and it will take the edge off. I have that amp and initially ran it ultralinear because I thought my Revels needed power. Tried the Brimar and thought they were a little bright also. Then swapped in the Mullard CV4003 and not bright at all. When I added the extra power of the KT150 I found I prefer triode mode. (I think KT150 in triode is 54 watts/channel.) So I put the Brimar back in for the gain tubes (the 2 in the middle) and the Mullard in the other 4 positions. Now it has more detail but is still super smooth. I have tried all Brimar and all Mullard but I like the hybrid combo the best.
johnread57's avatar
johnread57
45 posts
 
And yet...Trafomatic or Cary, Ayon, and Whammerdyn are other brands that I think compete with PrimaLuna. 
bruce_philly OP
28 posts
 
Leotis, I will try triode mode. 

Oddly, I never thought about it... I experimented with it on the EL34s and my JJ KT88s..... I didn't care for it... I think it is because the sound was a bit enemic.... I like a more dynamic sound.  Now with more power of the KT150s, yea, I will give it a try.... will start out a listening session in normal ultralinear mode to build a memory, and give it a try.
Are all Mullard CV4003 tubes the same?
As another selling point for PrimaLuna, notice in this and other threads the fun you can have rolling tubes.  I never heard of an amp that could take such a variety of power tube types.   Pretty cool and fun.  You can really tune the sound to match your taste or better match your speakers.

PeaceBruce in Philly
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