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KT77 vs KT88


eth2

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eth2:

 

What type of music do you listen to?

 

I don't own a VRD.   I see the following in Craig's web site:  "Valve Rollers Dream! The amps can run EL34, 6L6GC, 5881, 350B, KT66, KT88, 6550, KT90 and more (some tube choices require a 5U4GB rectifier tube)"

 

FWIW, the KT88 is not my favorite output tube.   (I listen to classical music and opera.  I own more than 2 dozen tube amps, in 5 systems.)   

 

Only you can decide which output tube you like with your music, your amp, your speakers, in your room.  With that said, if you want to hear a difference in sound quality, I suggest 6L6GC.  I can't say how 6L6GC will perform in the VRD driving KHorns, but IME 6L6GC have a "warm" sound that most people are seeking with a tube amp.   IME you don't need unobtainable (expensive) vintage 6L6GC tubes.   Try the  Russian military 6P3S-E - they are a great value in GL6GC equivalent tubes.  (Readily available on eBay.)  For aesthetics, consider the Tung-Sol 6L6G (coke bottle 6L6GC).  Whatever you decide, I suggest buying a tested, matched quad.  

 

IME, completely ignore any suggestion that "more output power is better".  In an average size room, with any reasonable volume level, you could drive your KHorns with a single-ended amp delivering 8wpc.  (Or possibly less.)  

 

Bottom line. 6L6GC will likely produce the biggest change in sound quality.   If you decide that you want sound quality between the KT88 and 6L6GC, then you might consider EL34 (KT77).

 

That's my 2 cents.  Hope this helps.

 

P.S.  Another great sounding 6L6GC:   Groove Tube Gold Series GT6L6GE Performance Rating 5.  

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The tube in the preamp will set the stage on the warmth and secondary harmonics from the power tube.  Getting the right preamp tube will go a long way in getting the sound to what you want and not so much the power tube.  It comes down to reaching saturation to a certain degree.

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19 minutes ago, jimjimbo said:

The 6L6GC black plates in my Mcintosh are magic.  Just sayin.....

 

I have vintage GE 6L6GC in my Scott 296, and vintage RCA 6L6GC in my McIntosh MC30s, and my Altec 353A.  Yes - the vintage tubes sound great if you're willing to spend the money. 

 

In my Inspire SEP amp, my favorite is the  Groove Tube Gold Series GT6L6GE Performance Rating 5.

 

In my MC240 I use Tung-Sol 6L6G (coke bottle 6L6GC).   (No tube cage.)

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12 minutes ago, derrickdj1 said:

The tube in the preamp will set the stage on the warmth and secondary harmonics from the power tube.  Getting the right preamp tube will go a long way in getting the sound to what you want and not so much the power tube.  It comes down to reaching saturation to a certain degree.

 

I agree that the driver tubes can significantly affect sound quality. 

 

IME, a great new production 12AX7 is the Genalex Gold Lion 12AX7 / ECC83 / B759 gold pin (Russia).  (NOT the Chinese variant.)  I also like the new production Tung-Sol 12AX7 (Russia), particularly if you want a "warm" sound.  (And the Tung-Sol are less expensive,)

 

A great new production 12AU7 is the Genalex Gold Lion ECC82/B749  gold pin  (Russia).

 

 

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In my listening... the 88's are better than the 77's. The 350b's are better than them both.

What ever you get, buy quality not quantity.

I've been less than impressed with the 6l6's that I have heard but I haven't heard any really pricey nos units.

What preamp are you using?

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2 hours ago, Schu said:

In my listening... the 88's are better than the 77's. The 350b's are better than them both.

What ever you get, buy quality not quantity.

I've been less than impressed with the 6l6's that I have heard but I haven't heard any really pricey nos units.

What preamp are you using?

What 350b's ?

I think mine are valve art but I'll have to check.

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12 hours ago, eth2 said:

 

Any thoughts on the sound difference between the KT77 and KT88? I have VRDs and am considering going to the KT77.

 

Sent from my SM-G935V using Tapatalk

 

 

 

No one can tell you what differences you may perceive.  You need to try it and draw your own conclusions.  Those tubes are generally run at different operating parameters so, other than assuming that some differences may be noted, it's not possible to have a clue about what those differences may be without knowing plate/screen voltages, bias, primary impedance of the opt, characteristics of the feedback network, and so on.  Why don't you ask Craig?  I would assume that he has some thoughts on this.

 

Derrick is correct in that the harmonic characteristics of the stages which precede the output stage can influence sound.  Again, it's up to the individual to experiment and draw conclusions accordingly.  However, trying different tubes of identical type (such as different brands of 12AX7) is not likely to produce changes which are audible (imho, of course).

 

 

Maynard

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2 hours ago, tube fanatic said:

 However, trying different tubes of identical type (such as different brands of 12AX7) is not likely to produce changes which are audible (imho, of course).

 

 

Maynard

It's interesting that you say this... it seems like you would have a lot of experience with different brands through the years so I'm surprised you've never heard a difference.  I have no doubt there are some audible differences.  These aren't huge differences but enough so that the overall synergy of the entire system can be slightly changed with the change of a tube brand.  Where I love the telefunken 12ax7 (smooth or ribbed) in a Scott 299 I don't like it near as much in the VRD where it makes things on the "bright" side.   Whether it is a matter of construction, materials, or measurements (or all of the above) that makes the difference is an interesting question but in the end doesn't matter as much to me as long as I can pick the tube that "sounds best" to me in a given piece of equipment.   It would be pretty cool if we knew all the variables, could measure them all, and recreate them in new products at will.  

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I own more than two dozen tube amps, installed in 5 different systems.   All amps have been restored, and are in good working order.  Tube rolling IME affects sound quality.  

 

Most amps only support specific tubes.   While IME there isn’t a huge difference in the sound quality of different manufacture’s tubes of the same type (e.g., 12AX7), I can usually tell the difference.   Here’s the new production 12AX7s that I tested a few years ago: 

 

Tubes_12AX7_new_1_2015_zpsgh6pndi6.jpg

 

(I also own many different vintage 12AX7s.)

 

Only one of my tube amps supports different types of tubes:  my Inspire SEP amp.   Changing the output tube to a different supported type results in a significant change in sound quality.  (Certain rectifier tubes must be used with certain output tubes.)  Similarly, different input tubes are supported. 

 

Here’s the output tubes that I’ve tried in my Inspire amp:

 

  • Zenith 6V6G (vintage)
  • Sylvania 6L6GA (vintage)
  • Sylvania 7408 (vintage, 6V6 variant)
  • Mullard EL34
  • Bugle Boy EL34 (vintage)
  • Russian 6P3S-E (Russian military surplus 1980s 6L6GC equivalent)
  • Groove Tube Gold Series GT6L6GE (6L6GC)
  • McIntosh branded GE 6L6GC (vintage)
  • GE 6L6GC (vintage)
  • Tung-Sol 7581A (6L6GC variant)
  • Tung-Sol 6L6G (6L6GC in a big bottle)
  • Gold Lion KT88
  • Tung-Sol KT150
  • Gold Lion KT66
  • Sylvania 5881

 

Here’s a pic of some of the output tubes I’ve tried (with various supported rectifier tubes) in my Inspire SEP amp:

 

Output_tubes_zpskftgwjth.jpg

 

Rectifiers that I’ve tried:  5Y3, 5U4, 5U4GB, 5V4, 5V4GA, 5AR4 (multiple manufacturers of each)

 

Front-end (9 pin miniature socket) tubes that I’ve tried:    6CG7, 6N1P-EB, 6DJ8, 6N2P-EV, E88CC

 

My results are irrelevant to anyone else.  First, my tube-rolling is based on an Inspire SEP amp, whereas the OP is using a VRD amp.   My speakers are Klipsch RF-7 II; the OP is using Klipschorns.   We are likely listening to different types of music, at different levels, in rooms with different acoustics.   And we probably have different preferences for which inevitable imperfections in sound quality we are willing to accept.   Because of the number of variables, tube rolling is subjective.   And a lot of fun … until it drives you crazy … :)

 

My suggestion to the OP is that he will probably hear a significant difference in sound quality with 6L6GC compared with KT88, and he can decide if he likes what he hears.  OTOH, he might find that he likes KT77s.

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what Robert said.  While different tubes have different characteristics, its difficult to predict how different tubes will sound in different products. Heck you cant predict 100% how different samples of the same tube from the same manufactuerer will sound, let alone different manufacturers. I will say this however, I have heard more amp designs over the years, that got more things right than wrong, with KT88/6550s, EL34s, and 6L6 varients. But the thing is you never know until you try.

 

 

 

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10 hours ago, robert_kc said:

 

 

Tubes_12AX7_new_1_2015_zpsgh6pndi6.jpg

 

 

 

Output_tubes_zpskftgwjth.jpg

 

Rectifiers that I’ve tried:  5Y3, 5U4, 5U4GB, 5V4, 5V4GA, 5AR4 (multiple manufacturers of each)

 

Front-end (9 pin miniature socket) tubes that I’ve tried:    6CG7, 6N1P-EB, 6DJ8, 6N2P-EV, E88CC

 

My results are irrelevant to anyone else.  First, my tube-rolling is based on an Inspire SEP amp, whereas the OP is using a VRD amp.   My speakers are Klipsch RF-7 II; the OP is using Klipschorns.   We are likely listening to different types of music, at different levels, in rooms with different acoustics.   And we probably have different preferences for which inevitable imperfections in sound quality we are willing to accept.   Because of the number of variables, tube rolling is subjective.   And a lot of fun … until it drives you crazy … :)

 

My suggestion to the OP is that he will probably hear a significant difference in sound quality with 6L6GC compared with KT88, and he can decide if he likes what he hears.  OTOH, he might find that he likes KT77s.

 

Don't hear a difference... try some better tubes. I dont think there is much of a difference in those brand above.

:P

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  • 3 weeks later...

I have had 3 pairs of VRDs.  They all do the same thing IMHO.  I have found changing the driver tubes has a much more noticeable effect than changing brands of output tubes.  I say "brands".  I always stuck with KT-88s............so I don't know what happens if you go to different power tubes.  But it was always the driver tubes that made the most difference.

 

Like others have said, you are simply going to have to spend the money and learn what you prefer yourself.

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  • 4 years later...

In my experience all signal/power tubes can make a 'difference'. After trying the crop of present makes in power and signal, I am now switching between Gold Lion KT88 and their KT77, and for signal tubes, NOS Brimar and Mullard. This is for the Rogue 88 Magnum. My pre (Audio Mirror T-61) uses the 6n1p and is presently running a NOS RCA rectifier. I am in the middle of tweaking a set of Devore 0/96 clones, and the KT88 are big and vociferous, but the KT77 are just perfect in terms of warmth, voicing and dare I say...fidelity (when using tube gear)...

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Initially I thought I really liked the KT 77 but they seemed to lean toward too much bass in my system.  One red plated after 10 months...so I put my spare KT88 Gold Lion in, they have many hours but still sound great.   

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