Seeking advice on tube amps

03-13-09: Jmcgrogan2
...he sounds like he is in the push-pull tube land. There really are very few
speakers that some tube amp cannot drive.

I disagree.

Driving speakers is more than an issue of plenty of power. It's also an issue of
balanced frequency response.

Ralph Karsten explains it better in his Atma-Sphere white papers, as does
Robert Harley in "The Complete Guide to High End Audio".

In your example of an 8 ohm nominal speaker dipping to 4 ohms, a tube amp
will produce less volume (decibels) into 4 ohms than it will into 8 ohms. The
difference to the untrained ear may be subtle, but the result will be a slight
tipped up sound that many describe as brightness. The reason the speakers
sound bright is that the bass response is not balanced due to the amp
producing less decibels in the bass frequencies relative to the high
frequencies. The highs are louder, thus the speaker sounds "bright". This
is why a solid state amplifier that doubles power as impedance is halved will
produce "better" bass on the same speakers. Since the SS doubles
power into 4 ohms, the decibel level of the bass frequencies typically found in
the lower impedances will be balanced with the decibel level of the higher
frequencies found in the 8 ohm region (and higher of course).

Yes, 60-75 wpc would probably be enough to produce very, very loud
volume on the 89dB speakers (depending on room size), but it will not
produce balanced frequency response on a speaker with a nominal
impedance of 8 ohms, and a minimum impedance of 4 ohms.

Balanced frequency response requires a speaker with a flatter impedance
curve, which is why Ralph Karsten recommends minimum impedance of 6
ohms on an 8 ohm nominal speaker.

Please refer to chapter 6 "Power and Integrated Amplifiers" in
Harley's book (Third Edition) for more information.

There's no reason to be afraid of tubes, nor is there any reason to be afraid to
shop for tube friendly speakers. There are many widely available options,
including some that are available with home trail periods. I have previously
mentioned several brands.

"I suggest finding some tube friendly speakers first (90+ dB sensitivity, 8 ohm
nominal impedance with dips no lower than 6 ohms)."

The fast track to happiness Tmesselt. Good luck.

I have owned a pair of B&W DM5 speakers for about 25 years. I powered these with a Yamaha CR 1020 receiver amp. I loved those speakers. While not producing tons of bass, for the music I listen to (jazz, classical) they produced to me, a very balanced smooth sound. The Yamy amp died some time back and was not economic to repair. I bought a cheap Pioneer one and the demise in sound quality was huge - the bass in particular had no definition. I then bought a NAD 3020A amp which improved things but still not to the level of the Yamy. Recently, the DM 5's also died. I have replaced them with a pair of B&W CDM1SE's. These are very different to the DM5's. Extraordinary definition - particularly in the mids and highs - I am hearing things in favourite recordings that I never knew were there. The stereo imaging is also very good. They are however to me, not as balanced as the DM5's and overall not as pleasant to listen to. The bottom end seems "veiled" in some way - almost hidden behind a layer of highs and mids. I realise that these speakers are probably not geared for lots of bass - I'm not looking for that but I would love a bit more overall balance and tonality. I am wondering if they really need a better/different amp to perform at their best. As you can probably gather, I am not on a huge budget. I listen to a lot of music but generally prefer to put money into my music collection than the hardware. I think I have pretty good ears though and have been a semi pro musician for many years. I am considering a Chinese tube amp like a Yaqin 10LMC which for $500 would perhaps be a bigger step up than what I could achieve with a solid state amp in the same price range? I have basic electronic knowledge so could probably handle the extra work required with maintaining a tube amp. I would welcome any thoughts/opinions/advice.