Speaker amps for headphones - Page 18

Folks:

I need to buy a multimeter to check my AC voltage, and because I should have one for various and sundry other things I need to do but didn't because I didn't have a meter and didn't care enough about the various broken things around here to go get one.  Do I need true RMS and a better quality meter to check accurately for the Cyclops bias calibration, or can I get away with a cheap one that doesn't have it, but does have an SPL sensor (I don't have one of those either... I know, shocking)?

Let me know ASAP so I can get something here in the next few days and start checking my voltage prior to delivery of the Cyclops.

Thanks,

Gary

Chris:

Actually, Klaus wants me to measure the AC voltage in the wall socket where the amp will be plugged in.  As I said earlier, he doesn't want me plugging into any power strips or power conditioners or anything else.  He will then tweak the amp to match the normal average voltage of that particular house AC electrical socket.

Does that change your answer about true RMS?

As to the SPL meter, I figured if I could get one included in the multimeter that would be one less tool to buy and sit in a drawer for months or years.  My first (and maybe only) use will be in making sure all of the different amps are putting out the same SPL for comparison.  I don't actually care what that number is, as long as it is the same for all of the systems.  I figure even a cheap one built into a multimeter can do that reasonably well. 

Make sense (sort of at least?)

Thanks,

Gary

Quote:

Originally Posted by Gary in MD 

Chris:

 

Actually, Klaus wants me to measure the AC voltage in the wall socket where the amp will be plugged in.  As I said earlier, he doesn't want me plugging into any power strips or power conditioners or anything else.  He will then tweak the amp to match the normal average voltage of that particular house AC electrical socket.

 

Does that change your answer about true RMS?

 

As to the SPL meter, I figured if I could get one included in the multimeter that would be one less tool to buy and sit in a drawer for months or years.  My first (and maybe only) use will be in making sure all of the different amps are putting out the same SPL for comparison.  I don't actually care what that number is, as long as it is the same for all of the systems.  I figure even a cheap one built into a multimeter can do that reasonably well. 

 

Make sense (sort of at least?)

 

Thanks,

 

Gary

Gary... Got an iPhone or other Smart phone?  I have 2 apps that measure SPL.  Not very accurate (mic isn't calibrated to the meter very well) but it is repeatable.

 If you are just measuring 60 Hz AC, a standard DMM should do just fine.  No need for true RMS.

If you don't have a smart phone, I have a Radio Shack SPL meter (brand new) I could send you for the duration of your testing.  Shoot me a PM.

Klaus can be over the top some times..  He's a very good sales person as well

Yeah, he is a good salesman, but he didn't say which kind to get, he just asked me to do the test.  The reality is that it isn't that hard to buy a cheap multimeter and check voltage, and I can think of other projects where I could use a multimeter, but didn't have one, so didn't do the projects.  I just needed to know if there was any reason to buy the ~$78 True RMS meter for this particular job instead of the ~$25-$35 non-TRMS ones.  If not, then I'll go with a cheap one, because my other projects aren't real demanding of precision (as in, finding if there is current to an outlet or switch without just sticking a fork in there...zzzzt... )

Okay folks, the speaker taps are here (thanks Ron!) and I have done my first comparison:  My old Sony STR-DE945 HT receiver vs. my old Adcom GFP-555 pre-amp, both fed analog out of my old Carver tube CD changer.  Receiver signal out via taps to stock Audeze balanced cable with 4-pin XLR.  Pre-amp signal out via headphone jack to standard Audeze single-ended cable.  We'll call it "The Old Leftovers Comparo".  Except that there is no comparison.  The Sony sounds like crap.  Not Schiit, though I really don't know what that sounds like, yet.  But I do know the Sony sounds like crap.

All of the realism, timbre, lushness, accuracy that the LCD-3s have to offer... gone with the Sony HT receiver.  Low end sounds like mud, high end sounds harsh and thin.  But the mids aren't totally awful.  Just not nearly as good as what I'm hearing from the Adcom.  Note that I only made it through 2 Sonia Dada songs before I gave up on the Sony, and I'll probably try a few more things, but there's no sense wasting my time on that option.  The Sony can go back to its dusty corner again... The Adcom has now vanquished the Sony and the Burson HA-160 (last summer).  Now I'm starting to wonder how good this old pre-amp really is.

I won't find out for a while:  the new contenders won't be here for another 10 days or so, since I really won't have time to do a fair comparison until then.  But it only took a few minutes to set the Sony up, and I figured I'd try it. 

Stay tuned for more exciting action...

Gary

Looking forward to more comparisons, Gary!! Keep 'em coming!!! 

Thanks for the update, Gary.  My Mini-X arrived today... :)  I had my resistor box inline with the speaker taps to do peak and RMS voltage measurements.  Discovered that listening straight off the speaker taps was much preferred to listening with a 10 ohm Caddock Metal Film in parallel.  I personally didn't expect the resistor to affect the sound stage so dramatically.  I guess metal film was the wrong way to go!

Thanks for your efforts, Gary.. looking forward to hearing about what you find.. especially with that TBI Millenia amp.