[miziq]

anyone have this combination and how it works

 

[jude]

When I was shopping around at one of the local hi-fi stores a little while ago, I brought my portable rig with me, but forgot the RCA-RCA-to-mini interconnect required by my portable headphone amp. Of course, the hi-fi store didn't have any such interconnect, so I had to find a way to drive the HD-600's I had with me. They had a Grado RA-1, and, based on things I've read before, I was afraid that it wouldn't sufficiently power the HD-600's. Wrong -- it powered them very nicely. I was prepared to have a sacrifice in detail and bass, and both came aplenty. I guess the concern might be how running the HD-600's might affect battery life, but I can't address whether or not it does.

Long story short: I thought the RA-1's sounded good with the HD-600's.

 

[hongda]

me and a friend tried it at his house through a NAD amp and CD-player, RA-1 and NAD CD-player. We had SR-325 and HD-600. The HD-600 with the RA-1 helped to tighten the bass and had a more dynamic sound. We both only had the RA-1 turned to halfway to get enjoyable level of music with Perfect Circle, Mazzy Star and some classical stuff.

 

[KR...]

I have this combo and it really sounds great! I have tried the RA-1 amp with the Sennheiser HD-580, HD-600 and even the MX-500 and they all sound amazing.

I only turn the volume control to about 9 if the dial was a clock. Therefore that's about 1/4 of the way to get the HD-600 and the HD-580 to play as loud as any could want them.

I have my amp hooked up directly to my DVD player.

 

[Beagle]

I have the RA-1 and use my HD600 with it. Sounds clean, open, spacious, detailed and natural. The RA-1 sounds terrific with the HD600 and my Grados.

 

[Tides]

I have Hd600 and Ra-1( proud owner of my new Ra-1, 6 days old)

I only spend like hmm 1 hour at most with the Ra-1 so I cant say much about it. From the little listening session I had with it, It *seems* to drive the hd600 pretty good. have not had the time to do a comparison.( actually dont care for a comparison here... as I did not buy Ra-1 to drive hd600)

I still use my xcanv2 mostly. That Ra-1 is reserved for the *elusive* hp1.

Tides

 

[miziq]

does 300ohms eat lot of battery power hom much aprox last , and do u have rechargable batteries...

thanx

 

[jude]

Quote:

Originally posted by miziq does 300ohms eat lot of battery power hom much aprox last , and do u have rechargable batteries...

That's actually a good question, and one I've been meaning to ask. Can any sage DIY'ers answer this one? All things being equal, generally speaking, would 300-ohm phones like the HD-600's deplete batteries faster than 32-ohm phones like Grados playing at equal volume? I know it's hard to answer because of other variables regarding headphone sensitivity, etc., but generally speaking, what's the story here? Don't the lower-resistance phones draw more current? Anyway, I've always wondered about this.

 

[Eagle_Driver]

I actually did a non-scientific battery-life test with a Panasonic SL-CT580 portable CDP I had owned with a pair of Sennheiser HD 590 full-size headphones (120 ohms impedance, 102dB @ 1Vrms sensitivity) and a pair of recently discontinued el-cheapo Sony E821 earbuds (16 ohms impedance, 116dB @ 0.5Vrms sensitivity) - and I tried to equalize the overall loudness levels (i.e. I had to turn up the volume control with the Senns just to be equally as loud as the el-cheapo Sonys)... SURPRISE!!

The setup with the bigger and higher-impedance Senns actually ran one-half hour longer than the one with the el-cheapo Sony earbuds!

(Though both setups ran longer than the claimed battery life rating.)

 

[thomas]

the impedence of the headphone has no effect on the battery life.

what matters is the Sensitivity rating (measured in dB@1mW). the higher the sensitivity, the lower the power draw for a given volume.

The power drawn is found by Voltage X Current (well, there are other factors in Ac audio, but they mean very little here)
Lower impedence headphones draw more current, but you'll end up playing them at a lower voltage (ie volume control turned lower). Meanwhile high impedence phones draw very low current, but they need more voltage (turn up the volume control). If you measured voltage and current for both high impedence and low impedence headphones, and multiplied these two together, you should end up with the same power if they have the same sensitivity and were playing at the same volume.

A potential problem with the RA1 is that it was designed for low impedence headphones, meaning that it can put out lots of current but not very high voltages. Even at full blast, it is probably putting out less voltage than an amp designed for Senns. As a result, there could be a problem reaching high listening levels if you used Senns with the RA1. But other reviewers have stated that they can get enough volume, so i guess this is not a problem (of course different people listen at VERY different volume levels, so this may not apply to you)

 

[thomas]

eagle driver- i guess the ratings for the headphones are kinda misleading, because the sensitivities are not rated based on power. (the standard)

The Sony's are rated at 0.5V. Power draw (simplified, not totally accurate, but accurate enough for this) is V^2 (Volts squared) / Z (impedence) x 1000 = 15.6mW.

So its sensitivity in traditional units is 116dB@16mW

The Senns are rated at 1V. Power draw is V^2/Z x 1000 = 8.3mW

So its sensitivity is 102dB@8.3mW.

so its comparing apples and oranges, they only REAL way to find the sensitivity is to use the proper units. (dB@1mW)

There is a general rule that the volume will increase by approx 3dB with a doubling of power, so you could say that the senns have a sensitivity of 105dB@16mW, but this is a generalization and does not necessarily apply and it probably is VERY inaccurate. And slight changes in earpad/earbud positioning DOES have a HUGE effect on the volume, so its really hard to measure volume output on listening alone...

And then keep in mind that in a CDP, the power used by the headphones is a TINY percentage of the overall powr used. A set of AA supplies 9watt/hours of power, only a few thousands of a watt are going through your headphones...

 

[KR...]

Here are the specs for the Grado RA-1 headphone amp :

1. Uses 2 - 9 volt batteries for up to 40 hrs of listening pleasure.
   
   Housed in a solid mahogany cabinet.
   
   Easily drives two Grado headphones
   
   measures 5(w) x 5½(d) x 1½(h)
   
   weights 12 oz.
   
   single line in
   
   single headphone output (drives two headphones with Y adaptor, not supplied)
   
   I.C. Daul Op/Amp - high current output, wide bandwidth, low current drain
   
   power output: 250 mw
   
   sensitivity: 600 mv
   
   signal to noise ratio: 85 dB.
   
   distortion(THD): less than .1%
   
   separation: greater then 50 dB
   
   frequency response: .1db, 20 to 20 khz