[Seamaster]

I am new to power amps.

1. Can anyone explain the difference in sound signature between 300B 2A3 KT88 EL34 tubes? I linsten to 50% rock, 25% pop, 25% classic or whatever sound good.

2. How about other tube options (sound signature)?

3. Why some people say don't use SS power amp with tube preamp?

Thank you for anyhelp.

 

[Seamaster]

any help?

 

[pabbi1]

I am the worst to comment, but will within my experiences with tubes.

Generally speaking, there is too much variation within each tube type to even start a conversation about between tube types.

For instance, el34 - there are such wild variations from the cheapest Mullard reissues / JJ, amongst the Russian variants (SED, etc) to the 'old' Mullards, and then amongst even the old Mullards, say xf4 < xf3 < xf2. There are also some pseudo pin compatible variants, like kt77 that just give a different presentation.

I am not qualified to talk and specifics about the tubes (plate voltage, etc), nor what can cause the differences (getters, flashing, pins, glass, etc), but can say it utterly dependent on the circuit / parts / iron as much as the tube variations.

A big topic, where, undoubtedly, there are better forums for this specific discussion.

For the record, the best tube I have ever heard is the 307a - and no clue what makes it 'better' than anything else - except it was brought to life by someone who REALLY likes that tube.

 

[Uncle Erik]

I don't know how helpful this will be, but there's more to a power amp than the tubes. I have a push-pull EL34 based amp and a SET 2A3 amp. They sound very, very different, but circuit topology has a lot more to do with that than the tube types. Or put it this way, you can get radically different sound from the same tubes used in different types of circuits. Or even just tweaking the circuits will make a change - the 2A3 amp has regulated DC power on the tubes. If you changed that to unregulated AC (as some advocate) it would sound different.

Moreover, the power supply changes the sound, too. You can rectify the AC with tubes or diodes. Each has its own sound.

If that isn't enough, each amp will react slightly differently based on the speakers it is connected to. Crossovers each have unique characteristics from brand to brand and individual drivers have very individual impedance curves and other quirks. An amp will sound different with each speaker it is connected to.

Confused yet?

First, do not look at this decision as a right/wrong choice. There are many amps that are reliable, sound good and will make you happy. The odds of finding one that meets those goals is good.

The best way to set about finding an amp is to find threads or a user group discussion of your speakers. Find out what the other owners use - there are people who have put a lot of research into the correct amp. Use their knowledge and advice.

Some people say you shouldn't mix tubes and solid state in a signal chain, but there's no good reason you can't. I've heard it done well, and am planning to do it myself when I get the final (?) speaker rig together. The Orion+ needs a multichannel solid state amp to power drivers individually from the active crossover. I can live with that, but I'm a tubehead, so I plan to run an Electra-Print Ultrapath preamp into it.

Sorry if this came across as sort of vague, but there are multiple factors beyond output tubes that have a heavy influence on sound. I think you'd be better of Googling your speakers with the word "amp," making a list of the models you get repeated hits for, then searching for that model along with your speakers' model for comparisons. You should be able to generate a list of contenders, then search more to learn more about each amp. Not exactly cut and dry, but you'll learn a lot along the way and, hopefully, other people will take a lot of the wotk out of it for you.

 

[TimmyMac]

2A3 and 300B are triodes and are mostly used in SET amps. They apparently have super sweet midrange, weak bass, and low power output, but people laud them as the 'purest' approach to reproducing music.

EL34 and KT88 are pentodes and usually used in push-pull amps. Power output can be higher but you get more odd-order harmonics. Not necessarily worse, but different and not as sweet and warm sounding.

 

[Seamaster]

Thanks pabbi1 and Erik 1st.

I had chance to get Melody I2A3 or Melody I880 from audiogon. One use 2A3 the other use KT88. I was not sure which to get so I emailed Melody. The tech told me sould buy KT88 base on my music reference: "Base on your favorite music listening, I would suggest that you go with I880. I880 is more dynamic, and more extended in low frequencies. High may not be as sweet as I2A3, but you don't need to be too sweet for hard rock and pops." One also told me 300B's are only good for low level listening, excel in mid and high. I understand each tube will sould different base on design. But should they have some general character by type right?

Now I have Supra Extreme XLR as headamp and preamp. But mine comes Plitron transformers to give more dynamic and detail. Speaker, I am learning toward singal driver design.

Thanks for input!

 

[Seamaster]

What is the big deal about singal end anyway? I have seen balanced 2A3 and 300B too. from what I understand RCA is one of the worse type connection. I have seen 5000USD amp is not even balanced. don't get it.

 

[Seamaster]

Anyone?

 

[pabbi1]

Sorry, this is really difficult to respond to. There are differences between the topologies *Balanced vs Single Ended), but it _all_ depends on the amp circuit (OTL, transformer coupled, push-pull, etc) (sorry for overlaps and generalizations), the components used (everything in the signal path, from connectors forward), before we get to the differences in the tubes.

Then to throw price into the mix just makes this topic too expansive for a quaint discussion.

Without a real starting point, it is hard to start scatter shooting, and, without collateral damage.

 

[Bostonears]

Quote:

Originally Posted by Seamaster /img/forum/go_quote.gif What is the big deal about singal end anyway? I have seen balanced 2A3 and 300B too. from what I understand RCA is one of the worse type connection. I have seen 5000USD amp is not even balanced. don't get it.

Even though they use similar terminology, the difference between single-ended triode vs. push-pull tubes is not the same as the difference between single-ended (RCA) vs. balanced (XLR) connections.

Here's a simplified explanation (although not strictly accurate, but it will give you the right idea):

In the case of connections, balanced cables carry the electric signal as a difference between sets of wires, where single-ended cables carry the entire signal over just one set of wires. Balanced cables are less prone to picking up noise, but their advantage over RCA cables only makes a difference for long cable runs or in environments prone to electrical noise. In typical home audio systems, the difference between single-ended and balanced connections is inaudible.

For tubes, push-pull amplification uses two tubes per channel, one tube for each half of the electrical signal wave. Single-ended tube (SET) amplification use just one tube per channel, and the one tube handles the entire signal wave. Push-pull offers more power, but their distortion is more audible, particularly at lower volume levels. SET tube amps are usually considered to have "purer" and more pleasing sound, and their distortion decreases at lower volume levels. Reproduction of midrange sounds, especially the human voice, is uncannily real from some SET tube amps.

 

[Uncle Erik]

Quote:

Originally Posted by Seamaster /img/forum/go_quote.gif What is the big deal about singal end anyway? I have seen balanced 2A3 and 300B too. from what I understand RCA is one of the worse type connection. I have seen 5000USD amp is not even balanced. don't get it.

First, do yourself a favor and read up on amps before you spend money on one. If you need book or website recommendations, please ask.

Not to ignite the controversy, but be aware that there is one qbout running balanced lines. I don't think it's worth the time or expense. Some do. I'm not going to go into it here, but be aware that there is an argument that balanced doesn't do much good. You may or may not agree, but until you sort out the differences for yourself, do not assume balanced is worth the premium and, especially, do not buy anything. Figure out what you're buying first.

Also, you can make a textbook argument that RCA jacks are inferior. In practice, they work fine. Again, you can slug out the minutiae, but there is a strong argument for using RCA jacks.

Finally, do not confuse price with quality or value. That's the wrong way to look at it. A 300B amp might have a huge amount of transformers and various iron inside. That stuff is expensive. There's no "insider" discount, either. The guys who build those amps pay a whole lot of money for the components.