Which tubes should I get?

How about using KT77 in place for EL34?

 

Well, all I know is that my amp can take EL34´s, and changing a switch, it can take KT88´s or KT120´s. If I can use any other type of tube like KT77´s I have no idea...

I´m new to tubes, and I´m learning as fast as I can from what you all are kindly suggesting to me, and I learn from other threads from this forum as well. I mean, as far as I could learn by not getting my own experience, that could be the way to go if I had the resources and if I lived in US or Europe for example.
Some of the options I´ve been given are harder to try than others... I think getting 4 EL34´s Tung Sol could be an option I could do, also getting 2 12AU7´s (could be NOS, since they are only 2 and if I could be sure I won´t get scammed, could also be Tung Sol´s) could be another option... Replacing EL34´s with some of the KT´s my amp can take is another option, but It could be more expensive and most people as far as I understood think I should stick to EL34´s,

You say we can put KT77´s on the table as well?

 

I think EL34 can use the KT-77. It may need a re-bias for fixed bias amps. The EL34 is a pentode whereas the KT-77 is a tetrode. Being a tetrode the KT77 sounds more like a KT88. Genelex makes a new KT-77 that have a large following.

 

Well, I bought this amp cause it's begginers's friendly, I would like to stick to what I can easily do by just swapping stuff... I wouldn't want to fix bias... That would be more complicated, I think there might be a lot of easier ways to improve bass, trade a little of mid highs with mid lows and keeping the realism I get in voices. As I said I wouldn't mind losing some highs.

I'd probably order 4 EL 34's and 2 12AU7's Tung Sol branded... Seems the easiest and cheaper way to get that according to what I've been suggested here. A few minutes ago, in a record shop, someone suggested me I should get KT120's instead of EL 34's, but I'm almost sure I will lost the mids if I go that way, from what I've been reading here.

 

I think that's a good way to go. If you think of the listening permutations that this offers, it's a nice selection.

1. 4 stock 12AU7 driver tubes + 2 TS 12AU7 gain tubes + Stock EL34s

2. 4 stock 12AU7 driver tubes + 2 TS 12AU7 gain tubes + TS EL34s

3. 4 stock 12AU7 driver tubes + 2 stock 12AU7 gain tubes + TS EL34s

4. 2 stock 12AU7 driver tubes + 2 TS 12AU7 driver tubes + 2 stock 12AU7 gain tubes + TS EL34s

5. 2 stock 12AU7 driver tubes + 2 TS 12AU7 driver tubes + 2 stock 12AU7 gain tubes + Stock EL34s

And so on.

A tip you may already have received: Don't replace everything at once. It's difficult to identify the source for change if you replace power and gain, or gain and driver, or any two or more combinations at the same time.

Good fun!

 

You can use any tube that is in the EL34 or KT88 family.

KT77's will give you a similar midrange (speaking of modern manufacture tubes) as EL34's but with more bass, but not as much bass as you will get from KT88's, comparing apples to apples.

Your PrimaLuna Dialogue Premium has Adaptive Autobias. You just remove your EL34's (with the power off) and replace them with KT77's or KT88's turn your amp back on and you are all set to go.

Change tubes any time that you like, with your PrimaLuna Dialogue Premium, you never have to bias any tube. This is done for you automatically by the amp.

 

Yes, now I understand what you say, this is also what allied333 was trying to explain, but I didn´t understand him in the moment, I´m like doing a crash course in tubes, mostly without trying them out.

So far, I think I have 3 valid possible choices, for power tubes as far as I´ve been collecting by suggestions in this thread and some others from this forum, and some people that are tube users that I have personally asked:

1)Stay with EL34´s, by buying the tung sol´s which everyone says will give me more bass without losing mids.

2)Go to Kt77´s, I think it will be more or less the same than option 1, maybe a little more punch, since they are in the middle of kt88´s and el34´s. This is fine, as long as it doesn´t give me more highs that I don´t really need or want. I believe kt88´s do that, so that´s why I don´t consider them (must say I never really listened to any kt88´s as far as I know, so this is just from what I´ve read.

3)This third option is really interesting to me to try, since someone I know runs them, and invited me tomorrow to listen to them: get some Tung Sol´s kt120.
The guy said more or less something like this: "If you´re pleased with el34´s mids, but you want more bass and you won´t mind trading some highs but not the top end, it´s worth to try these tubes that will give you the punch you are wanting, and they are not as aggressive as kt88´s. Probably some of the magic will be lost, but, if you go this way, then you can do the fine tuning with only getting 2 12au7´s.
Since this person owns the same amp I do, I think it will be interesting to go to his home tomorrow and see how this works out. Speakers are totally different, anyway, it´s still useful to go and give a try. I will bring my el34´s to do the comparisons.

If I´m not pleased with kt120´s, then it would be either 1 or 2. I think I will be ordering whatever I decide next monday and once I run them for 1 or 2 weeks, I will see what I´d like for the preamp. If I´m pleased with kt120´s, I´d order them and same for 12au7´s in the next step.

 

I would go with 4 of these

Winged "C" (SED) EL34 Audio Tubes - www.thetubestore.com

and something like this in the center 2 spots:

Mullard M8136 / 12AU7 Wrinkle Glass Made in Great Britain

 

KT88's are NOT bright. I despise bright tubes. I have A7's and believe me, the very last thing that I want to do with them is to feed them with "bright" sounding tubes.

With the KT-120's you WILL give up the midrange that you will get with the EL34', KT77's and the KT88's.

They will have more bass and more top end then the KT88's or any of the other tubes.

Keep in mind, that even though you can put larger tubes like KT90's KT-120's or KT-150's in your PL, you are not going to get the benefit that these tubes can provide, because your amp is designed to run at far lower plate voltages then these tubes are designed to operate properly.

Also, bare in mind that transformer's are optimized for a particular type of Voltage and tube.

It may be better for you to stay away from tubes that are designed to operated in more powerful amplifier's than the KT88's.

Your PL should be able to operate with KT88's just fine.

If you want the most bass, and not more high end, then KT88's might by your best alternative.

KT-120 tubes are more linear and less tube like sounding than the other three smaller tubes that I have mentioned.

I have a Cronos Magnum (I), and it has KT-120's. They are not my favorite tube.

They are not my favorite tube not because there is anything wrong with them (and they are in an amp that is designed to power them at 100-Watts), but because of the type of music that I mostly listen to, the SLP's that I listen and the high efficiency speaker's that I use.

If I listened to large orchestral arrangements at higher SPL's or Rock concert's at these same levels, then the KT-120's would be an ideal tube for me.

As my preferences are with acoustic instruments, jazz, vocals and the like, I don't gravitate toward the KT120's.

Just my personal preferences.

With Monitor Audio speakers, I would want to increase the bass output, while staying clear of tubes or SS that might tend to accentuate the HF.

 

First 2 days with my new PRIMALUNA PROLOGUE and I'm loving it..So far the bass is tight and fast and very detailed in the upper end...Ive noticed that if a record or cd is recorded bad then that's what I hear(shy on the bass)but if its good then the right amount of bass is there ..So I need a couple weeks for my decision..Hope you are getting the help you need...you might also want to email UPSCALE AUDIO and ask them what's best, they are the US distributer.

 

You have said something here that is very important and well worth repeating.

I think that people often want to upgrade their gear because something does not sound as good as would like for it to sound.

A better reality, is that when you have program material, be it a record, CD or whatever, and you have a repeatable number of these sources that do sound good and what you expect to be there, be it bass or something else, that IS telling you that your system is balanced and that it can produce great music.

When it fail to produce what you expect, it is because of the source and not your system.

That does not even mean that the source is necessarily bad, it just might not be right for your system.

Years back, many stereo systems were just single speaker systems, There was not brightness or such a thing as bass definitions.

This is just the kink of equipment that the general public had back then.

Mass produced records sounded fine on what they were being played on.

They very well might not sound good on a current quality resolving system that might bring out that recording's shortcomings.

In that case, that recording is not right for your system. Nothing more to it that that.

 

Stevie Ray Vaughan sounds awesome!!!

 

Okay everyone here has much more experience than I do with tubes. I got really lucky. When my C2500 was pretty new I wanted to start tube rolling I got Gold Lions the Russian tubes, I at least learn that those were better than the cheaper Chinese tubes. The difference was noticeable but small. Then I start posting up asking members here what they liked and one poster said he helped is brother with his c2500 and they tested many 12ax7 tubes vintage and otherwise. They liked RCA black plates. I went online and found a dealer how posted on ebay 4 matched 1958 RCA black plate they were not NOS but tested good used. It also was somewhat of an improvement or so I thought. Later on a year or two shortly after I got my Rogue ST100. I contacted him again wanting to try some other tubes. After figuring out that I really had no idea what I liked he sent me a box of tubes to try both 12AX7 and 12AU7, on his dime I squared up with him later.

I spent about a week listening, recording and listening again. It was really cool here's what I figured out. Nobody can tell me what on my system I will like. The truth is they all sounded good or at least none of the ones he picked out sounded bad but they were different. So I ended up with Mullard GE 12AX7s for the MC phono stage, Telefunken smooth plate 12AX7s for the line in and Amperex both 12AX7 and 12AU7 for the ST100. Nobody can tell you what flavor of ice cream you like, this is no different.

 

I always talk to Jim McShane. Great, great guy. He has pointed me in good direction many times. Although currently I am running solid state

 

Way too soon to get serious about tube rolling.
Just sit back, relax and enjoy what you have for (quite) a while.

 

I use Jim for new tubes.

Good point get to know how it sounds now so you will know what sound better to YOU.

 

I have the PL Prolugue Five. I run it either with NOS RFT EL34s, or cryoed Gold Lion KT88s from Upscale. The RFTs do indeed have the midrange magic as well as well as suprisingly deep and yet controlled bass. The KT88s are more linear, but still a really good sounding modern tube. The only issue with NOS is quality control. One of my RFTs went bad after a week or so of use (loose pin) and I had to source another single.

John K.

 

That is like that? Even if I switch the amp to the kt88-kt120 position? It´s like 0 for el34´s and 1 for the other two...

 

are you using the 8 ohm taps or 4 ohm taps,,you can switch and see maybe other sounds different ,my manual recommends to try it and see what sounds best...just a thought

 

My speakers are 8 so I plugged them to the 8 ohm taps... But it´s true, manual encourages people to try both for 4 or 8 ohm speakers, haven´t done that so far... In spite of what manual says, I don´t think why I should plug my 8 ohm speakers to a 4 ohm...

 

A lot of good suggestions, here's mine for you. Go online and buy a matched set of JJ el34 tubes (not the el34L) and try them. Probably the least expensive good new production el34 tube. I have a quad running in my dynaco st70 and they really sound excellent. I've used the new Mullard el34, the JJ KT77, EH6CA7 and the JJ el34's are the best sounding new version. I also have many NOS el34's and the JJ's hold there own sound wise. Cheap and easy to get too. Good luck.

 

Thanks for your advice... For how long have you been running them? Lots of people says they fail a lot, I even read that they can be dangerous and you could damage your amp... That´s why so far I didn´t even consider that brand...

 

Have had them in for about a month. Just make sure to buy them from a reputable supplier. I also have used JJ KT77's for about 6 months with no problems at all. Gave them to a friend that needed some new tubes. They're less than $20 each so not a large outlay of money. Not sure how much they'd be in Argentina though...

 

Here if I go to a shop, a tube that costs $20 online in an US seller, for example, could easily cost me $50-70. I´ve seen those jj el34´s for $100 a pair for example. And you can´t really find much variety. That´s why whatever I decide, I´m planning to order online, that, with shipping costs and taxes once they reach Argentina may cost me $40 at the most.

 

Viva Tubes in the U.S. has great customer service if they can ship to you. Have fun, let us know how everything turns out.