[Bill]

I have a T5 preamp and have had limited use with the headphone jack. I'm not really a headphone guy, but I have a few questions. When I used a pair of Grado SR60's (30 ohms) the SPL seemed reasonable. I had to turn the volume control up more than an old Musical Fidelity X-Can which seemed really sensitive. With the X-Can the sound was loud quickly and soon distorted. With the T5 the sound was smooth and never got unrealistically loud. However, I'm thinking Sennheisers with 300 ohm sensitivity might be too much for the T5 output, but maybe AKG's with sensitivities closer to the Grados might work. Does anyone have any experience with these issues.

Thanks guys (and maybe girls), Bill

[rlee8394]

The higher the impedance, the easier the load. You should have no trouble with the Sennheisers.

[BradJudy]

The higher the impedance, the easier the load. You should have no trouble with the Sennheisers.

This often isn't true with headphones because the limitation of the headphone driving circuits is often the voltage they can swing rather than the current they can output (which is usually the restriction on a speaker amp).  Headphones intended for mass market consumer use are almost always ~32 ohms so they can be driven by iPods, Walkmans, etc. 

Having owned SR-225's and HD-600s at the same time, I can definitely say that the low impedance Grado is easier for a typical device to drive than the Sennheisers. 

[Bill]

I think I was getting sensitivity and impedance ratings mixed up. It seems sensitivity of the headphone is a bigger issue than its impedance in determining the power required to drive it. If two headphones have identical sensitivity ratings then the one with lower impedance would be easier to drive. This is simplistic I realize and it depends on the amp, but in this case I am only concerned with the headphone section of the AVA T5. What are its limitations with commonly used headphones, in particular AKG's.

Thanks again, Bill

[charmerci]

I have the SR-220's. When I use it with my Omega III, they don't get very loud but clean sound doesn't sound as loud as ear-wrenching distortion that we normally expect from "loud." My suspicion is that it's a combination of the two.

[turkey]

I've used headphones with the built-in headphone amps in the OmegaStar and Insight preamps. I have also used a box I made up years ago to allow headphones to be driven by a power amp. (I based it on plans in Audio Basics.)

I've used the Grado SR-80, Sony MDR-EX71SL (recommended by Linkwitz), Yamaha HP-1, and also the AKG K240.

The built-in headphone circuits sound at least as good as using the power amp, and are less noisy too.

I think I would also say that built-in headphone amps sound better than a number of other dedicated headphone amps I've listened to.

If I were living in a small apartment, I think I could be quite happy with an AVA DAC, preamp, and a good set of headphones.

[avahifi]

Insight preamplifiers have much nicer headphone drive capabilities than our older solid state units.  These improvement will be made to any older AVA solid state preamp (Super Fet, Omega, OmegaStar, etc) in for upgrade here at no extra cost.  Dyna Pat-5 based units headphone output are driven from the connected power amplifier so no change is made with them.

Regards,

Frank Van Alstine

[Listens2tubes]

I use Senn HD600's with my first gen T8 and love it. I would like to take this setup to a headphone meet but pulling the preamp out of the system is a pain. As per comparison my Grado 125's seem to need only slight volume adjustment with the T8.

[Bill]

Thanks for the input guys, but I'm specifically wondering about the T5. Are there some headphones out there that this unit won't drive to realistic SPL's ?

Bill

[turkey]

Thanks for the input guys, but I'm specifically wondering about the T5. Are there some headphones out there that this unit won't drive to realistic SPL's ?

Bill

It will work just fine with the Grados, so why worry about it?

Or you could go with the Shure E2c or SCL2 earphones if you want an in-the-ear phone.

You can see what Linkwitz had to say about the E2c here: http://www.linkwitzlab.com/reference_earphones.htm

[Bill]

The reason I'm worried about it is because I am thinking of selling the unit and the person that might be interested wants to know if it will drive AKG's, Senns and so on. I used to have Grados but that was some time ago.

[avahifi]

The T5 headphone driver is an AD845 IC configured for either a gain of 5 or unity gain, depending upon when it was built (most current is unity gain).  This will drive our 30 ohm Grado SR225 headphones very well.

The headphone circuit can be upgraded to our latest configuration, with a unity gain current amplifier instead of a op-amp.  This will provide more current drive and better musical results.  The pin outs for the devices are very different so we have to see the units for any changes desired.  I don't have a flat price for this, just time and materials. Its probably not necessary with the stock T5 circuits as the stock headphone amps are probably nearly as clean as the audio circuits in any event.

Regards,

Frank Van Alstine