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Hi All!
I need some recommendations for some NOS tubes for my dad's new Prima Luna Prologue 7 monoblocks. They originally came with 4x Ruby KT-88 and Groove tubes 2x 12ax7 and 2x 12au7 per monoblock. Oviously we weren't impressed by the sound created with these new production tubes... they were overly bright, almost harsh, with little to no soundstage. Very disappointing! I would really appreciate any recommendations you guys could give. I want to get my dad some new tubes for christmas, but I don't know too much about NOS tubes.
Thanks!John
Follow Ups:
Hi Chuck, I’d be interested in what you’ve found to be best with the PL3 & 5. I have NOS Mullards (including rectifiers) in my 3. And currently I’m experimenting with 6l6GCs in the 7s. The change from KT88 to 6l6GC in the PL7 definitely has pluses and minuses. There’s no doubt the KT88 has more weight and resolution, the 6l6GC is warmer and I do like them, but they are not “better”. I may try the Shuguang GEKT88s as they seem to get a lot of favourable comment.One thing though FWIW in my experience new tubes in the PL seem to take longer than you might think to bed in and start sounding good. At first, and for many hours, they can indeed sound bright and harsh. You just have to be patient.
be sure that the tubes are the critical issue. I don't have the 7's. I have a 5 and I can assure you that this unit without the Primaluna 3 pre-amp ahead of it sound threadbare, i.e. bright and little bass.Just so you can do your own addition read the review of the 3 & 5 on 6 moons, then read the review of the 3 and 7 on Absolute Sounds and do the math.
Now if you have the Primaluna 3 ahead of the 7's I'll be happy to pass on to you the tubes I've used in my 3 and 5 to get a well balanced, linear sound. FWIW.
My dad used to have an old dynaco tube amp with mullard EL34s that had glorious sound... it brought tears to my eyes. When my dad purchased the PL7 monoblocks he was so disappointed. The sound out right of the box was cold, harsh, too bright and lacking in bass response. We are running the same custom designed preamp in front of the PL7s as we were running in front of the dynaco. (it was designed by a family friend who has been in the tube amp scene forever. I'm not quite sure what is in the mystery preamp box...)My dad was so upset that he spent a bunch of money and got a product that doesn't measure up to his standards. I'm just trying to fix that without breaking the bank. Is buying the PL preamp the answer? We don't want to drop more money and still be disappointed by the sound. We thought tube rolling might be a MORE affordable solution to our problem.
Should we just let the stock tubes sit in the PL7's for a while and let them get comfortable? How many run hours do you think it will take before the stock tubes warm up and start sounding decent? Did your PLs sound good right out of the box?
Thanks again guys! There really is a wealth of information on this board. I've had never been here until I posted, but I'm glad I found the Sound Asylum!
I have a 5 and have never liked the KT88's that came with it. I love EL 34's in it. Currently SVET EL34's. So much more warm and musical. I noticed the difference right away without a lot of hours on the amp. Since then I've got nos Mazda chrome ax7's and nos Radiotechnique au7's which really increased the resolution and sound stage. I'm driving Maggie 12's. I recommend trying some nice EL34's first to get that warm musical sound he is used to.
A thumb nail - 6moons review sez the PL3 is a good pre-amp in a universal sense but the PL5 driven by other pre-amps lacks bass which will diect you attention to the mids and highs. The PL3 and PL5 were quite a good combo and the missing bass appeared.The Absolute Sounds review of the PL3 and PL7's commented on the PL3's sound falling a bit short with other amps, that is the top end was not as resolving as possible, but when connected to the 7's there was no shortage of upper range detail, and that the combo was excellent. PL3 has fuller bottom end + PL7 has brighter top end = balanced combo.
I have run the PL3 with other amps. On two amps I get a result similar as TAS reviewers, that it the highs were rolled off, the sound stage was more closed in. Using a PL5, as well as
another tube amp made by Cary, it was a fine combo.I've not had personal experience with the 7's. Obviously it takes time for any amp to burn in, both the amp as well as the tubes. It is also critical which tubes you select but that will depend on the other components you are using as well as the speakers and the sound you most enjoy (I ultimately chose SED 6550's for my PL 5 and I use EH12AX7 and EI12AU7 which combine to give a very neutral linear sound lacking the upper bass bloom typical of the KT88's and a slightly soft upper mid's and highs. These do not have a euphonic mid range so many might not like them. I do.
IMHO your dad has 2 options 1)Buy a PL3 - then with some fiddling with tube changes you will be able to fine tune the sound to get what you want, or 2) sell the PL7's. If the 7's are like the 5's you will never get, IMHO, the final sound that you want just by making tube changes or going thru lengthy break-in.
I would think, in view of you dad's experience (disappointment) he'd be better off just to sell the PL7's. He probably wouldn't lose much and could get equally good, or better, more universal amps in the same price range.
Hope that helps you a bit.
NT
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