[Schoenberg]

I have a set of KEF speakers driven by Rotel power amp. I also have headphones sennheiser HD650 and akg K501. With speakers, I will listen to headphones much less often. But I cannot give up Senn or AKG completely.

I need a preamp to connect to my power amp. Probably I prefer a tube preamp.

Or shall I get a tube headphone amp instead of a tube preamp. Can I find one tube amp/preamp to do both job decently at the same time at a low price?

HD650 and K501 really need much much power to drive. If I go for a tube preamp, I am not sure if it can drive headphones to the level I need. Many amp drive headphones between 28 and 300 ohm. I actually need an amp capable of driving more than 300 ohm, say, 600 ohm.

For a preamp, power might not be the most important. I am not sure if I understand correct since I live little experience with any preamp.

I welcome all recommendations less than $500. both used and new. made in china, usa, japan and all other countries. ALL ARE WELCOME.

Shall I give up the dream to find an amp/preamp to do both jobs decently? shall I just buy separate items for different usage?

 

[Uncle Erik]

First, impedance is not what you think it is. It does not tell you how hard headphones are to drive. Sensitivity (measured in Decibels, or dB) tells youmhow hard something is to drive. Impedance only matters in the context of the output impedance of your amp. The relationship between the output impedance and headphone impedance tells you how power transfers from the amp to the headphones.

As for a preamp or headphone amp, yes, there a number of units that do both. I also think there are several threads in the Amp Forum listing models.

I'd think twice about any inexpensive tube amp. Most of them cut a lot of corners in design and construction to push price as low as possible. I'll get some knocks for saying that and a lot of people who love their amps will jump in, but I think you get a higher level of quality and safety with solid state at a low price. I won't own a piece of gear with cheap power transformers. It's not worth the sonic compromise and risk.

Also, the K-501 is (IIRC) 62 Ohms, so your typical cheap OTL amp won't cut it. You'd need an amp with transformer-coupled outputs to drive it properly. Output transformers aren't cheap, you often have to pay $100-$150 per transformer for good ones (you need two) and then everything else in the amp.

My advice would be to find a used solid state preamp from Audiogon that has a headphone jack. There are lots of them and you'll get better performance and value for your money. Don't think you're compromising if you don't have tubes - solid state can sound wonderful.

 

[Schoenberg]

Thanks, uncle Eric.
Can I just get a Solid state preamp and use adapter/cable for headphones?(ie. RCA out connecting to headphone plug)
do headphone jack need a separate circuit?

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif First, impedance is not what you think it is. It does not tell you how hard headphones are to drive. Sensitivity (measured in Decibels, or dB) tells youmhow hard something is to drive. Impedance only matters in the context of the output impedance of your amp. The relationship between the output impedance and headphone impedance tells you how power transfers from the amp to the headphones. As for a preamp or headphone amp, yes, there a number of units that do both. I also think there are several threads in the Amp Forum listing models. I'd think twice about any inexpensive tube amp. Most of them cut a lot of corners in design and construction to push price as low as possible. I'll get some knocks for saying that and a lot of people who love their amps will jump in, but I think you get a higher level of quality and safety with solid state at a low price. I won't own a piece of gear with cheap power transformers. It's not worth the sonic compromise and risk. Also, the K-501 is (IIRC) 62 Ohms, so your typical cheap OTL amp won't cut it. You'd need an amp with transformer-coupled outputs to drive it properly. Output transformers aren't cheap, you often have to pay $100-$150 per transformer for good ones (you need two) and then everything else in the amp. My advice would be to find a used solid state preamp from Audiogon that has a headphone jack. There are lots of them and you'll get better performance and value for your money. Don't think you're compromising if you don't have tubes - solid state can sound wonderful.