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First Tube Amp

I have been listening to a 90's SS amp(200 wpc @ 8ohms) for 25 years and thought I would finally give a tube amp a try.

I ordered a $500-800 chinese push pull(40 wpc) integrated tube amp, with 4 El34 tubes, and  2 12AX7, and 2 12AU7 tubes. 

I figured this would introduce me to the so-called "tube-sound", perhaps an exaggerated version, that I have been reading about on this forum, then after a week of exposure, most likely return it for a full refund and decide if I want to go down the hole further with more prestigious versions.

To my surprise, I am floored by the quality of sound it produces. I wasn't expecting this at all. Initially, I thought it had some distortion of the high frequencies and a bloated low end but after 75 hours of break-in this essentially disappeared. The bass is thunderous, contrary to the limited reviews on the internet. The quiet passages are dead silent. I am hearing very different interpretations of CD's that I have listened to for years(classical) on my SS amp. Particularly when single instruments are played the sound is unbelievably sweet. Pizzicato is more forward. Part of this new experience I owe to the newly acquired speakers, which have opened up a sensitivity to recordings that I have not known to exist - I hear musician movements and breaths in the orchestra at 98.82dB 2.83V@1m .

I am struggling with returning this amp, in the midst of a paradigm shift: chinese junk has become on par with high end, how can it get better than this? What would other types of tube amps of better quality offer? How would other types of tubes("rolling") sound. How would a SET amp sound different(a 300b SET). A PL(also chinese made) with an array of tunes versus some of the boutique models that have half as many tubes?

Thanks for your help.




recluse
jsm71
141 posts
 

Congrats on taking the leap and seeing what all the fuss is about. It took me many decades before I had the nerve to try tubes and ultimately change my system to exploit tubes for all my electronics. I won’t be going back to solid state. It took me three tube amps and two preamps before I nailed down what I believe is best for my speakers. Hopefully you got lucky right out of the gate.

What speakers are you using, and what is the impedance rating for them? Mating speakers to any amp is very important. At 98db efficient you very likely have plenty of power to drive them. If the amp/speaker match makes for great "dance partners", you have solved a challenge some never do. It took me a couple of gear swaps, but I have it now.

You asked about tube amp types. The amp you described (push-pull, 4 EL34, 2 12AX7, 2 12AU7 tubes) is a very common and proven tube amp design. Pricing and sound quality are functions of build quality (circuit boards or hand wired), parts quality including tube choices, labor rates, fit and finish, and always the quality of the output transformers.

SET amps benefit from simpler designs with less parts in the signal path, and a more pure sound from the tubes, although with lower power output. These amps are where owners of very efficient speakers (98db qualifies) often tend to gravitate to, due the beauty of the sound. There is an entire sub-culture that lives in the high efficiency world. I don’t play here. My speakers need 40 or more watts, so I’ve been tied to push-pull designs.

The only other major category of tube amps are OTL designs, amps that eliminate the iron core output transformers, the hardest component to get right. These often offer stunning sound with amazing sound stage, but come with other realities that may bring higher cost into the picture. Not to confuse you further, but David Berning designs also fit into the OTL category in that they also avoid the iron transformers, but use completely different methods to manage the speaker impedance handshake.

All tube amp designs benefit from using better tubes. This will drive you crazy but really turns this into a hobby. Enjoy what you have for now. All the tube types in your amp give you lots of options should you take that step into the abyss.

jsm71
141 posts
 
I like Atmasphere's post better.  Less words.  LOL.
lpretiring
463 posts
 
"what speakers are you using,"

Just a guess here but 98.82db 2.83V @1m is a exact match for the rated spec of the Tekton double Impacts. They are available in 4 or 8 Ohms.

Only the OP can say for sure, but that's where my money goes.

  LP
swampwalker's avatar
swampwalker
5,138 posts
 
Welcome to the wonderful world of vacuum tube audio.  A word of caution on SETs.  In your OP, you talked about classical, which can have a very wide dynamic range.  Although your speakers are quite high efficiency, these peaks can require lots and lots of power (logarithmic relationship between volume and power).  This is important because an SET amp's distortion rises quickly with power output.  A 300b SET makes about 8 watts. Even if you do not drive the amp into clipping, you may start to hear that distortion as a kind of harshness and a loss of the SET "bloom" for which the amps are prized.  Depending on your room size, listening levels, etc., this may or may not be a problem for you.  In my 14 x 23 x 8' room, I eventually gave up on 8-12w SETS with 94-96 dB speakers, even though I listen to music that does not have the wide dynamic range of classical.  I settled on 2 amps having 30 wpc; one OTL and one push-pull.  Lastly, do not get hung up on topology or tube type.  Once you get past basics, it's implementation (and for non-OTL amps, transformer quality) that is/are key.  There are GREAT tube amps using OTL, PP, and SET circuits, with EL-34, 300b, KT-88, EL-84 etc, etc power tubes. 

And +1 to the idea of a tube pre-amp. 
recluse OP
270 posts
 
Thanks for responding.

As someone already mentioned, speakers are 8 ohm, the DI’s, and the amp is Yaquin. Speaker cables are 6’. My room size is on the small side and I don’t particularly like to play music loud.

Roxy , which 300 b do you have?

By bloom do you mean harmonics. Atmosphere, I think I found the corresponding website ;-) how would something would sound with loss of “low-level detail” which is what happens with push pull amps. I’m guessing more “bandwidth” is more frequency response or range?

Do SET,s lose their”bandwidth” or fail only when pushed to hard/loud?


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