[Loquah]

The HE-400 is a planar magnetic. Output impedance of the amp is irrelevant.

 
As I understand it, the planars have no problems with frequency response fluctuations caused by poor impedance matching, but from what I've read the lack of electronic damping in planars means they rely on damping via the amplifier to prevent "flapping". Is this correct?

 

[palmfish]

1. The impedance of planar magnetic drivers is flat so it presents the amp with a constant load across the entire freq band, therefore there are no changes in frequency response due to varying loads.
2. The driver is not a suspended push/pull mass that suffers from rebound and thus requires no dampening.

 

[brunk]

   
As I understand it, the planars have no problems with frequency response fluctuations caused by poor impedance matching, but from what I've read the lack of electronic damping in planars means they rely on damping via the amplifier to prevent "flapping". Is this correct?

 
Yes, that's what i understand, that current coming out of an amp plays a big role in starting and stopping the planar, reducing over/under shoot.

1. The impedance of planar magnetic drivers is flat so it presents the amp with a constant load across the entire freq band, therefore there are no changes in frequency response due to varying loads.
2. The driver is not a suspended push/pull mass that suffers from rebound and thus requires no dampening.

Ok, i understand this as well, since there is relatively zero impedance fluctuation from the planar, it doesn't need the extra "guidance" so to speak.
 
Thanks to both of you. Some of this i had either forgotten or had a vague understanding in regards to the planars.

 

[Mahdi8]

I've tried mad dog 3.22 which is an ortho with the crack speedball. Really nice MIDs, high and imaging. Albeit slightly cold. The main issue is the bass it's really loose and blubbery

 

[Mahdi8]

BTW any closed headphone user with the crack here? I use dt770 600ohm. The upgrade path for closed headphone and crack seems to be limited

 

[Loquah]

1. The impedance of planar magnetic drivers is flat so it presents the amp with a constant load across the entire freq band, therefore there are no changes in frequency response due to varying loads.
2. The driver is not a suspended push/pull mass that suffers from rebound and thus requires no dampening.

 
Agree with 1. Not sure about 2.
 
From what I've read, there is no mechanical damping of the driver (like the suspension which causes the push/pull/rebound effect) and therefore can get "loose" if not sufficiently damped electronically (by the amp circuitry). I haven't played with planars yet in order to test this for myself.
 
Does anyone here have a planar they can try with the Crack and compare to a different, low OI amp as a comparison?

 

[palmfish]

As I understand it, the planars have no problems with frequency response fluctuations caused by poor impedance matching, but from what I've read the lack of electronic damping in planars means they rely on damping via the amplifier to prevent "flapping". Is this correct?

The term "poor impedance matching" doesnt really describe how or why the freq response changes. To visualize what is happening with the headphone-amplifier relationship, you must understand what is causing the impedance swings in some headphones (resonant frequencies) and how those swings change the way the amplifier drives them.

Electrical damping is a vague term. Damping or dampening is a mechanical force; the act of controlling extraneous driver movement (rebound). That force can be electrical (from the amplifier) or mechanical (from the driver suspension), but the force felt by the driver is the same. Planar magnetic drivers dont "move" like acoustic suspension drivers do, so they dont have a resonant frequency. No resonance, no need for damping.

Maybe an engineer will chime in and correct whatever mistakes I have made.

 

[Mahdi8]

Well the main different with crack and solid state or hybrid amp I've tried for the mad dog (o2 and torpedo parafeed) is the bass is significantly better on the others but I actually prefer crack for the rest of sound quality. Most likely because crack has a better sound stage and smoother sound overall

 

[Loquah]

Well the main different with crack and solid state or hybrid amp I've tried for the mad dog (o2 and torpedo parafeed) is the bass is significantly better on the others but I actually prefer crack for the rest of sound quality. Most likely because crack has a better sound stage and smoother sound overall

 
Thanks Mahdi. When you say the bass is better do you mean tighter, looser, more quantity, etc.?

 

[Mahdi8]

I've tried mad dog 3.22 which is an ortho with the crack speedball. Really nice MIDs, high and imaging. Albeit slightly cold. The main issue is the bass it's really loose and blubbery

Thanks Mahdi. When you say the bass is better do you mean tighter, looser, more quantity, etc.?

You might miss my previous post. The combination with mad dog makes the bass loose and blubbery to the point sounds like low frequency distortion to me. Especially the mid bass. Mad dog sounds much better with other amp. Well unless music you listen has no bass then that combination has pretty good sound.

All depend what you normally listen to I guess

 

[Loquah]

You might miss my previous post. The combination with mad dog makes the bass loose and blubbery to the point sounds like low frequency distortion to me. Especially the mid bass. Mad dog sounds much better with other amp. Well unless music you listen has no bass then that combination has pretty good sound.

All depend what you normally listen to I guess

 
Thanks. I had forgotten that post. I think this looseness is the "flapping" I have read about where the amplifier doesn't provide sufficient electronic damping to stop the diaphragm once it's moving, hence the distorted, loose sound.

 

[Aeolus Kratos]

  has anyone else tried the crack with HE-400s? I know its not ideal, but strangely I get a weird distortion/buzzing when I hook them up. I have the crack with speedball and it sounds beautiful with my other high impedance phones. 

I'm in the same boat, I tried a HE-400 with my Crack and actually I couldn't even listen to it longer than 5 minutes because of distortions.

 

[HolyCheese]

HolyCheese, you could use a tube shield. An aluminium tube covering the tubes, it replaces the metal ring covering your tube socket. Something like that: http://www.ebay.com/bhp/vacuum-tube-shield.

Hmm Those are pretty ugly. I like the nice glowing in the dark.
 
 
And placing doesn't really matter since it happens anywhere on my desk. It's next to my laptop but that's on LAN and the wifi comes from my bed 2 meters away. The router is much further away. I don't even live in a busy place with alot of wifi around..
 
 
What about the alternative non 12au7 tubes for this amp?

 

[olegausany]

You can use 6SN7s but you will need to get adapter for them

 

[amcananey]

I would say: don't bother.

I do NOT have any problems with noise from my router (or any other source), but I have 4 of those adapters from 3 different manufacturers and all of them induce intolerable noise with 6SN7s. You can avoid the issue by building a separate power supply for the input tube, but all I can say is: it's not worth it. The Crack sounds great with 12AU7s, so why chase other tubes that are highly unlikely to be an improvement?

An easier option would be to try changing your router.