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In Reply to: RE: Tube rolling preamp or power amp gain tubes, which ones (or both)? posted by 2121@comcast.net on January 16, 2017 at 04:46:39
Both. I select power tubes 1st then fine tune with the small tubes. The power tubes make the biggest difference when selecting the type, then the brand.
It helps a lot if you have sonic goal in mind when selecting your tubes. If you do you might get some meaningful recommendations.
Follow Ups:
"It helps a lot if you have sonic goal in mind when selecting your tubes. If you do you might get some meaningful recommendations."
Agreed. Without a sonic objective one's just spinning their wheels when it comes to tube rolling. And in this case, the combo of tube amp & tube preamp = a lotta' tubes that could be swapped out. Wouldn't take too long to burn a sizeable hole in the old wallet if the NOS bugs hits.
I don't see that as spinning wheels. I can define a sonic objective but I'm still back where I started, which is, "Okay now that I want the sound to be such-and-such, do I get closer to that sound by rolling the gain tubes on the pre, or amp, or both?"
What does my already knowing the specific changes in sonics have to do with my "point" in asking for advice that has nothing to do with knowing the specific changes. I recommend you re-read my initial and subsequent posts, or alternatively confine your misguided complaint to those posts where it has relevance.
Maybe I'm missing something here, but if you already know the specific changes in sonics you're looking to achieve via tube rolling, what's the point in asking for advice if you're not willing to share those sonic objectives w/ those of whom you're seeking assistance?
Ahh, I did not know that, that the power tubes make the biggest difference.
And so just to confirm -- and we are talking about only the power tubes for the amp -- those get selected first (based on a desired sonic outcome). Then afterwards, one begins a process of "fine-tuning" with gain tubes.
Okay, so assume I have selected the power tubes (or that I like the sound of the stock power tubes and have decided to retain and use those), I still have a choice at that point to swap out gain tubes on either the pre-amp, power amp, or both. What is the selection process now? Does the greatest sonic change occur with changes to the preamp gain tubes? Or to the power amp gain tubes? Does it not make a difference which gets changed because the sonic difference either way is not appreciably significant? And further, once a decision is made as to on which device gain tubes should be changed (assuming there is an obvious choice), would swapping out tubes on the other device produce even more of a sonic change (so much more that most people would judge that change to be worth the investment in the additional tubes)?
I have a Dialogue Premium (non HP) and have been going through tube rolling for awhile. There are many great points here and I am still not where I want to be either sonically. What I have found so far is the stock amp sounds very very good but missing a little something for my tastes. One thing I have found is the stock tubes have a sense of timing or cohesiveness that I like however when I have rolled in other power tubes this timing goes away somewhat. The power tubes set the tone and the preamp tubes tailor the sound to your liking. The stock power tubes lack a little pop and overall soundstaging so I have been trying to achieve this by trying various power tubes. I love the EL34 sound so recommended were the GL KT77. They are really nice tubes and close to the EL34 but definitely more pop. Still wanting to try others I rolled in Mullard re-issue EL34. Nice tube but a little something was lacking. Don't get me wrong these are good tubes. I bought the amp from Upscale Audio and purchased the KT120 which I rolled in after getting used to the stock sound. Hated the 120's. Way too grainy and upper midrange glare and couldn't tune it out with Mullard CV4003 (12Au7). Sold them and purchased some Tung Sol KT150. These are nice tubes and they have a wonderful soundstage, slam, and a very nice midrange unlike the KT120. However the stock timing isn't there so my chase is still on lol. One tube that I have found that is awesome is the Cifte 12AU7. I suggest you try this tube in the front 2 slots. They make a LOT of difference. I have currently gone back to the stock EL34 and contemplating trying another power tube like a KT66 or a 6ca7. Yes tube rolling can get expensive but once your realize what tone you like then work it from there. I still haven't ruled out the KT150's altogether as they have some very nice characteristics (slam, soundstage, tone) but the stock cohesiveness isn't quite there.
samzx12, the other option you may want to try are Mills Wire wound on all the plate and cathode positions on your amp. The stock PL resistors are metal oxide, very rugged but not known for the sonic qualities.
the PL Dialogue is quiet now, but you will hear more micro detail withe MILLs in place, while at the same time removing some of that high freq. edge the metal oxide Resistors add.
best
How would I go about this and what kind of sonic qualities or differences would the Mills Wire make? Thank you!
Sam
determine what resistance values are needed, order them and solder them in place.
the MILLs improve focus and low level detail without adding any brightness.
Thank you for the information. Just another curve ball thrown in this crazy hobby lol ;)
Lets assume for a moment that you like the overall sound of your amp/pre amp in your present system except that you find the upper mid range a bit bright. In that event I would put a different pair of 12AU7's in the center sockets of the amp - I would make sure that the tubes had a reputation for a soft or slightly mellow upper mid range. If that made any difference at all towards your goal than I would get another pair an put them in the center sockets of the pre-amp and see if that improved the sound more.
Lets say you like your present systems sound but you might like a bit warmer bass (a change I don't usually experience much with small tube changes) you might try a Tungsol 6550 power tube (a tube I use in my Primaluna for just that reason and FWIW I use a new stock Mullard 12AX7 as it softens the highs slightly something that is useful as my system is based on CD's, not vinyl. If I wanted a more linear sound than the Tungsol I'd try a GL KT88. If I wanted a tube with less bass but a very clear linear mid/high end I would try Sovtek KT88's. But FWIW all of these recomendations are based on my use of them in Primaluna products.
The permutations of tube combinations and consequential results are, seamingly endless, so do not expect definitive advice beyond the mechanical.
Other posters mentioned the importance of matching your amp/pre-amp to your source. Unfortunately your source can have some (negative) impact on your ultimate sound. But sources change from year to year, or day to day if you have multiple sources. Finding an ideal amp/pre-amp for both, i.e. vinyl and digital (or multiple) sources can be a real challenge if you have very high end expectations of the sound of both.
Hope that helps a bit.
I would agree with Chuck Y. Have both the HP and non HP versions of this amp. Would have to say I hear a bigger change with power tubes, but again depends on which tubes power tubes. I like a warmer sound so pulled the stock PL power tubes and inserted Mullard KT88 re-issue tubes.
The input or front end tubes will make a difference, but mainly its the first two 12AU7s that will have the largest effect. The other 12au7s is minimal by comparison.
As some of the other posters noted, the cost of tube experimenting can become large very fast. If you have friends that will let you try out a set of power or input tubes that is one option.
and as mentioned previously, coupling caps can make as big or bigger difference in the sound. PL uses metalized SCR caps in both the HP and non HP amps. they are ok, but not great. If you like the sound of the SCRs, a quick swap to the white film and foil SCRs will give you greater detail than the stock caps.
best
As someone taught in my youth as a buyer for a chain of slightly upscale audio salons back in the day, that one always approached any upgrades from the Source downwards, as these tend to have the most adverse impact on the sonic integrity of everything which receives the proper signaling further downstream.
In other words....., your preamp tubes should be addressed after the power tubes ( NOS or Current Production ) as the voicing here then effects how one goes ( or should ) about fine tuning according to " your taste | ears " said gain ( preamp | signal ) tubes in ones Power amp bring about a sense of synergy and tonality above all else.
And do note, that it's not always a good thing to use any one brand of tubes more then once in ones system, as it then brings with it all of its strength and weaknesses that should be altered counterbalance wise by using different brands to create a collective whole......., and one that's easier to come by once said person understand how each factories voiced their tubes to begin with......., and while I'm a proponent of NOS preamp tubes, I can see where power tubes made between say 1960 to now can in fact bring beautiful sonics to the table......, it's again all about which type of voicing the end user is pursuing that matters.
Just keep in mind......., Source first, followed by ones Preamp | Integrated | Power Amp ending at the Speakers and lest not forgive the vital role of the cabling loom itself........., as it makes or breaks the vital sense of cohesiveness needed to draw the listener into what's going on with the musical notes them self, as opposed to merely listening to the components.
Is your goal also in line with the actual amp and general setup you have?
I'll give you an example. A few years ago I bought a Conrad Johnson tubed preamp with the simple minded idea that it had that classic tubey preamp sound. Well it DIDN'T!. And no matter how much tube rolling I did that never happened.
I later began to understand the sonics of the CJ preamp and now I would not change it for the world. BTW that also happened with the amp I also bought. Fate has a funny way of bringing you places you never imagined you would get to.
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