Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Amp recommendations for Audeze LCD-2
New Posts  All Forums:Forum Nav:

Amp recommendations for Audeze LCD-2 - Page 489

post #7321 of 7721

^^^    Lyr with Amperex tubes.    I had the original tubes and swapped them out a couple of days ago and oh. my. lord.....

post #7322 of 7721
Quote:
Originally Posted by Poladise View Post
 

 Anyone know of any other low powered tube speaker amps available in the UK?

The best tube amp I ever heard was a Wheatfield HA-2, designed by Pete Millet. It is a SET OTL design. It's discontinued but Pete has the schematic on his web site for DIY, and they show up for sale occasionally here and on eBay.

However, I never listened to the LCD-2 on this amp.

post #7323 of 7721
Quote:
Originally Posted by MRC001 View Post
 

The best tube amp I ever heard was a Wheatfield HA-2, designed by Pete Millet. It is a SET OTL design. It's discontinued but Pete has the schematic on his web site for DIY, and they show up for sale occasionally here and on eBay.

However, I never listened to the LCD-2 on this amp.

If it is an OTL amp, I don't think it will have enough currently for the LCD's or any other planar and low impendance headphone.  

post #7324 of 7721

Not sure what the Wheatfield HA-2 puts out, but the Little Dot Mk VI+ is  an OTL which puts out 5W at 120 ohms.

post #7325 of 7721
Poladise that's a shame about the Taboo - it (the mk II version) and a CSP2+ preamp survived their journies to New Zealand 3 and 2 years ago perfectly. They were well packaged by Decware - tons of bubble wrap; paper and double-boxed. Bad luck, as I find my (neutrally tuned) Taboo superb with both LCD2 and LCD3FZ.

I had no idea the LD VI+ had that much power! I have an LD 1+ hybrid that's a surprisingly great match with Grados.

MRC001, great recent posts in this thread and your LCD2 review - outstanding :beer chug:

Edit: I can imagine vkalla's Lyr/Amperex recommendation is very good. I found Lyr with stock tubes syrupy with LCD2, but with Matsu tubes it started to show it's potential and it was easy to believe the top picks in the mammoth Lyr tube-rolling thread were good indeed.
Edited by AiDee - 4/27/14 at 3:34pm
post #7326 of 7721
Quote:
Originally Posted by Zashoomin View Post
 

If it is an OTL amp, I don't think it will have enough currently for the LCD's or any other planar and low impendance headphone.  

You're probably right. The HA-2 has an output impedance of 100 ohms and max rated power is 400 mW into 270 ohms. It was well matched to the Sennheiser HD-600 at 300 ohms but the LCD-2 at 50-60 ohms may not be a good match for it.

post #7327 of 7721
Quote:
Originally Posted by MRC001 View Post
 

You're probably right. The HA-2 has an output impedance of 100 ohms and max rated power is 400 mW into 270 ohms. It was well matched to the Sennheiser HD-600 at 300 ohms but the LCD-2 at 50-60 ohms may not be a good match for it.

Current delivery will be more since the total impedance is less with the LCD, but I think 600 is more sensitive, so it can react more to less power than the LCD.  These are specs though.  I don't like the low impedance relative to the ouput though(not sure what affect it would have on planars).  I don't think damping factor comes into play for planars since it has no resonance like like dynamic drivers.  So impedance mismatch shouldn't matter?

post #7328 of 7721
Quote:
Originally Posted by SilverEars View Post
 

Current delivery will be more since the total impedance is less with the LCD, but I think 600 is more sensitive, so it can react more to less power than the LCD.  These are specs though.  I don't like the low impedance relative to the ouput though(not sure what affect it would have on planars).  I don't think damping factor comes into play for planars since it has no resonance like like dynamic drivers.  So impedance mismatch shouldn't matter?


The LCD-2 has slightly higher voltage sensitivity than the HD-600: it plays slightly louder on the same volume setting. That doesn't mean it's more efficient though. It's lower impedance, so at the same voltage it's drawing more current, which means more power.

 

The problem with driving the LCD-2 with an HA-2 is the LCD-2's low impedance. As a general rule, you want the amp's output impedance to be much lower than the headphone's impedance. That's why tube amps designed to drive speakers usually have an output transformer. The HA-2 is designed without one, because it's relatively low powered and designed to drive headphones 200 ohms and higher, so the OT is not needed, and it only adds complexity and is just one more electrical part to color the sound.

 

Note: You'll read different opinions on this but I believe damping factor does matter even with orthos. Everything has a resonant frequency, including an ortho's driver membrane. If it flaps back and forth it generates its own voltage just like a dynamic driver does. The amp's output impedance is what the headphone is "driving", and if that impedance is low, it requires more power/current which sucks up the energy faster, damping the motion. If I had to guess why there is some debate on whether damping factor matters for orthos, I'd say an ortho's Q is probably less sharp and the amount of EMF it generates is lower, so damping is less of an issue than it is with a conventional voice coil driver.


Edited by MRC001 - 4/27/14 at 4:53pm
post #7329 of 7721

Well, 600 is more sensitive, 97dB/mW for HD600 and 94 for LCD-2.  LCD-2 draws slightly more power, but HD600 provides more dB/mW.

post #7330 of 7721
Quote:
Originally Posted by SilverEars View Post
 

Well, 600 is more sensitive, 97dB/mW for HD600 and 94 for LCD-2.  LCD-2 draws slightly more power, but HD600 provides more dB/mW.

Sensitivity and efficiency are completely different things. Sensitivity is about voltage, efficiency is about power. To simplify, wensitivity tells you how loud it will be for a given position of the volume knob. Efficiency tells you how much power it's going to draw at that volume knob position.

 

According to Inner Fidelity, the LCD-2 is more sensitive, but less efficient.

 

The LCD-2 is more sensitive: the same voltage plays slightly louder.

LCD-2: 0.225 Vrms for 90 dB

HD-600: 0.230 Vrms for 90 dB

The LCD-2 is 0.2 dB more sensitive

 

The LCD-2 is less efficient: the same power plays quieter.

LCD-2: 0.87 mW for 90 dB

HD-600: 0.17 mW for 90 dB

The LCD-2 is 7.1 dB less efficient

 

Having compared the LCD-2 and HD-600 side by side, I can tell you the LCD-2 plays a bit louder at the same volume knob position. The specs suggest they're only 0.2 dB different which would not be noticable. But subjectively, the difference sounded much bigger than that; it was quite noticeable. I had to turn it up for the HD-600 and down for the LCD-2, to match the levels.


Edited by MRC001 - 4/27/14 at 6:42pm
post #7331 of 7721

Ok, I've gotten efficiency and sensitivity mixed up.  When it comes to volume level and loudness, it's sensitivity.  The volume level is voltage without load. I'm assuming.

post #7332 of 7721
Quote:
Originally Posted by MRC001 View Post


The LCD-2 has slightly higher voltage sensitivity than the HD-600: it plays slightly louder on the same volume setting. That doesn't mean it's more efficient though. It's lower impedance, so at the same voltage it's drawing more current, which means more power.

The problem with driving the LCD-2 with an HA-2 is the LCD-2's low impedance. As a general rule, you want the amp's output impedance to be much lower than the headphone's impedance. That's why tube amps designed to drive speakers usually have an output transformer. The HA-2 is designed without one, because it's relatively low powered and designed to drive headphones 200 ohms and higher, so the OT is not needed, and it only adds complexity and is just one more electrical part to color the sound.

Note: You'll read different opinions on this but I believe damping factor does matter even with orthos. Everything has a resonant frequency, including an ortho's driver membrane. If it flaps back and forth it generates its own voltage just like a dynamic driver does. The amp's output impedance is what the headphone is "driving", and if that impedance is low, it requires more power/current which sucks up the energy faster, damping the motion. If I had to guess why there is some debate on whether damping factor matters for orthos, I'd say an ortho's Q is probably less sharp and the amount of EMF it generates is lower, so damping is less of an issue than it is with a conventional voice coil driver.
I've read this type of explanation countless times. I understand the science behind it but no one has ever explained how it affects the sound. and it's pretty much impossible to do any A/B test because you'd need an amp that allows you to set the output impedance, which I've never seen.

Can anyone shed some light?
Edited by bassboysam - 4/27/14 at 7:22pm
post #7333 of 7721
Quote:
Originally Posted by bassboysam View Post


I've read this type of explanation countless times. I understand the science behind it but no one has ever explained how it affects the sound. and it's pretty much impossible to do any A/B test because you'd need an amp that allows you to set the output impedance, which I've never seen.

Can anyone shed some light?

Hey, I don't disagree with you.  We're just talking about specs that's all.  Specs are useful to have a basic idea of the gear.  

 

I can't do a proper A/B tests myself, but I do try to compare gear as I try to move up when I get a new DAC or Amp.  I swap out DACs with the same Amp, and do the same with Amps, and use my ears to find out which sounds the best.  After all, it's how the setup is heard that you will be enjoying.

post #7334 of 7721
Quote:
Originally Posted by bassboysam View Post


... no one has ever explained how it [damping factor] affects the sound. and it's pretty much impossible to do any A/B test because you'd need an amp that allows you to set the output impedance, which I've never seen.

I mostly agree and mentioned it only as a secondary concern. I believe the primary reason you want the amp's output impedance to be less than the headphone's impedance, is because otherwise its likely to be current limited and clip before reaching reasonable power outputs.

post #7335 of 7721

Also, is it safe to assume that headphones have varying efficiency at different frequencies? Would this explain why planars seem to sound more full with more power? I.e. that a more powerful amp can handle less efficiency at lower frequencies?

 

All just hypothesizing on my part to try and understand better so don't flame me if this isn't the case. ;)

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Amp recommendations for Audeze LCD-2