Head-Fi.org › Forums › Summit-Fi (High-End Audio) › High-end Audio Forum › Speaker amps for headphones
New Posts  All Forums:Forum Nav:

# Speaker amps for headphones - Page 105

Yes no hiss when music is playing

That sounds more like a fault in the source than the amp. What if you play a blank track?

Quote:
Originally Posted by ALRAINBOW

Yes no hiss when music is playing

Then I wouldn't worry about it. Unless of course you prefer to sit listening to silence instead of music.

se
Lol. I understand it is not broke.

Al D

I understand how to calculate resistance with combined parallel and series resistance but I don't understand how the Resistance In and Resistance Out in this schematic was calculated. Could someone give a brief explanation?

Also, how was the Attenuation calculated?

Rob

Search me!  (But I feel for you!)

Quote:
Originally Posted by robrob

I understand how to calculate resistance with combined parallel and series resistance but I don't understand how the Resistance In and Resistance Out in this schematic was calculated. Could someone give a brief explanation?

Also, how was the Attenuation calculated?

Rob

What amp was this calculated for?  Either they are using the output impedance of the amplifier as part of the Resist Out (as they should) or I'm missing something...

Their "attenuation" doesn't take into account the impedance of the headphone, so Attenuation is calculated wrong.  It would be close for anything 600 ohms and higher.

The "attenuation" they have calculated is just the voltage divider ratio:  Vin/Vout = (R2 + R3)/R3

Resist In (the resistance seen by the amplifier) is calculated as R1 || (R2 + R3).  But, the impedance of the headphone is not included in the calculation, so its not quite right.  You need to put (R4 + Rheadphone) in parallel with the above so you'd have  R1 || (R2 + R3)||(R4 + Rheadphone)

Thanks potterma, I don't know what amp or phones this was calculated for. It's the translation from Italian of the network posted very early in this thread.

Is Resist Out the resistance seen by the headphones? (((Amp Impedance || R1) +  R2) || R3) + R4

I have a Lyr which I I love, but Steve Eddy made me some speaker adaptors, so I can connect my Trends amp too (I just wanted to experiment).  Not using any resistors, I hear a lot of hiss with the Trends amp, however it does sound quite different from the Lyr, and when music (at least compressed music) is playing, I don't hear the hiss - it sounds very good considering it is a suboptimal setup.

Quote:
Originally Posted by robrob

Thanks potterma, I don't know what amp or phones this was calculated for. It's the translation from Italian of the network posted very early in this thread.

Is Resist Out the resistance seen by the headphones? (((Amp Impedance || R1) +  R2) || R3) + R4

Yes, resist out is apparently the resistance seen by the headphones.

I knew I had seen that circuit somewhere before, but it was too long ago... Didn't remember it was from this thread...

Anyway, why the interest in such a complicated network?

Quote:
Originally Posted by NinjaHamster

I have a Lyr which I I love, but Steve Eddy made me some speaker adaptors, so I can connect my Trends amp too (I just wanted to experiment).  Not using any resistors, I hear a lot of hiss with the Trends amp, however it does sound quite different from the Lyr, and when music (at least compressed music) is playing, I don't hear the hiss - it sounds very good considering it is a suboptimal setup.

Quote:
Originally Posted by potterma

I need to get my SET 300b amps up and running again - I expect to be amazed !

Quote:
Originally Posted by NinjaHamster

I need to get my SET 300b amps up and running again - I expect to be amazed !

Be sure and post your results!
Quote:
Originally Posted by potterma

Be sure and post your results!

Will do !

Quote:
Originally Posted by robrob

I understand how to calculate resistance with combined parallel and series resistance but I don't understand how the Resistance In and Resistance Out in this schematic was calculated. Could someone give a brief explanation?

Also, how was the Attenuation calculated?

Rob

I can't think of any arrangement where you would need R4 in that diagram.

R2 and R3 form your voltage divider

R3 is roughly the output impedance seen by the headphone (assuming R3 is small, which it should be)

Quote:
Anyway, why the interest in such a complicated network?

I'm working on a spreadsheet that will calculate values for networks using 4, 3, 2 and 1 resistors.

If you only use R1, the amp load resistor, will that affect the impedance the headphone sees too? It seems like it would.

New Posts  All Forums:Forum Nav:
Return Home
Back to Forum: High-end Audio Forum