#### solderdude

##### Grand Contributor
You need 5.6V for 120dB SPL peak.
HD650 can handle 12V continuous (125dB SPL)

A50(s) SE = 7V so enough.

#### Spojkovic

##### Member
A50(s) SE = 7V so enough.
and on balanced its double like everything else right? and where are you getting these voltages from? that for example A50 (maybe A50s is the same) has 7V

but its hard to tell what i am getting with 2.1 Vrms input, for example in A50 specs it is SE 2x 160mW @ 300Ω, balanced 640mW @ 300Ω, its not stated at what input signal strength, if 2 Vrms or more, but in case of A50s there are two different specs, at "x" Vrms -> SE [email protected]Ω, balanced [email protected]Ω and 2 Vrms -> SE [email protected]Ω, balanced [email protected]Ω (i dont know what i need to get full power from A50s if its not just some marketing)
but from my experience i think A50 specs are at 2 Vrms because i run A50 without dedicated DAC just from motherboard that has 1.1 Vrms and i had lots of power, when i got A50s, i had to get dedicated DAC (Topping E30) to feed it at least 2 Vrms, that was in case of Beyers 250ohm

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#### solderdude

##### Grand Contributor
A50 = +9dB (3x) gain, A50S = +6dB (2x) gain is what determines the max. output voltage .
In both cases it is more than sufficient for HD650.
Balanced is double the output voltage.
You will have turned down the volume on your amp (when used balanced) before you reach maximum levels.

A 50 from Mobo = 3.3V max = 113dB peak balanced out = 6.6V max (119dB)
A50s is less gain (2x) but when used balanced out = 4x the input voltage.

#### Spojkovic

##### Member
im feeding amp (now its A50) with Topping E30 now so it should give them 2.1 Vrms, at least that is what amir measured on that DAC
i will probably have to switch to low gain with A50s on balanced
i just have to wait for cable delivery and RMA of A50s
cant wait for it cuz A50 is boosting treble a bit, at least it was the case with Beyers, when i switched to A50s, i changed my EQ because suddenly there was not enough treble clarity, on A50, i had it on -9db at 5750Hz and on A50s i changed it to -6db and still it was not that sharp
so i think A50s will be ideal for HD650 because now i have a problem in some songs with sharp treble or highs or what and im lazy to tune it when it will be tuned by it self when i get A50s

Thanks for your help, i read some other post from you before when i was reading through some threads on this forum and it seems you are an expert

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#### solderdude

##### Grand Contributor
A50 is boosting treble a bit,

It cannot do that despite you clearly hearing it. Both amps do not 'lift' any part of the frequency range.
The output resistance of the A50 (5 ohm) is way too low to have any influence on a 250 ohm headphone and if it did there would be a fraction more midbass using the A50. The same effect should be had on the HD650 as well.
Beyers always have boosted treble, certainly opposite HD650.

The Beyer treble can be tamed without having to resort to EQ.

#### Spojkovic

##### Member
im using slightly tuned oratory1990s EQ for HD650 and i was using it for Beyers too and i heard a difference between A50 and A50s at that 5750Hz frequency... this is his EQ for Beyers i had and as i said, with A50s i change that -9db to -6db at 5750Hz and i was trying to change band 9 and 10 too because i heard a difference somewhere and i heard the biggest difference at band 8

i dont know what is the cause but it was there.... i will let you know if i can hear a difference with HD650 when i get A50s back and i will compare SE to SE because DMS in his review said that balanced on A50s sound a bit better on every headphones he tried and he clarified that he is not saying balanced is always better, only in case of Topping A50s, sound is a bit better on balanced

#### solderdude

##### Grand Contributor
3dB is in a narrow band is simply something no amplifier can ever cause.
I do not doubt you heard it but this is not amplifier related. There is no electrical 'mechanism' for this.

#### Spojkovic

##### Member
so i have my A50s back and i can hear the difference on Sennheiser too, its in vocal range, it sounds like A50 is boosting vocal range and A50s is not
A50s sounds a bit better than A50, i feel like A50s delivering equal power in all frequencies and A50 is not, if that makes sense

but i heard a bigger difference on Beyers

now i wait for balanced cable to arrive and im curious what difference will be there, SE vs balanced on A50s

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#### GimeDsp

##### Senior Member
I have been using the HD650 as reference for tuning a studio acoustic set up and I just love all the music on them!

They are light in the bass but man these sound good! SMOOTH and clear and all my songs sound good. Just wish they felt more comfortable for me.
Most enjoyable pair I've listened to.

#### solderdude

##### Grand Contributor
i feel like A50s delivering equal power in all frequencies and A50 is not, if that makes sense

My best guess would be that you know which amp is playing. Both amps are technically incapable of actually doing what you describe and most certainly in the amount of dB's you mentioned. Even the 4.7 ohm output R of the A50 is utterly inconsequential for 300 ohm headphones.

When you are interested in finding out the truth you will need an RCA splitter so you can connect both amps at the same source.
Then you need to match the volume of both amps as closely as possible.
You will also need someone to assist.
That person needs to unplug the headphones from an amp and either reinsert in the same amp or the other amp.
To let him decide which amp to plug it in can be be chosen by coin flip, dice or some random generator app or something.
The trick is you cannot see which amp is being used (maybe turn your back to it).
You can pause, rewind and start tracks and use digital volume control and ask to 'switch'.
Then at least 20 attempts have to be made where chance determines A or B after you call 'switch' .
The one doing the cable swapping must note which amp is being used.
You have to note what you think you are listening to.
Then compare both notes and see how well you scored.

This is the only way to really find out. Knowing what amp you listen to will always reveal the same difference. Simply because you know and have a bias.

You should only do the above (complicated) test when you really want to find out if the differences are real and of electrical origin otherwise just use as is.

#### Spojkovic

##### Member
Just wish they felt more comfortable for me.
Most enjoyable pair I've listened to.
for me they are very comfortable, the stronger clamp is more preferred for me at least, so all the weight is not on top of my head but it is reduced and of course i love the velour pads, thats why i have Beyers, thats why i got these

i hate that fake leather on headphones, it start to crumble after some time and its not that comfortable as velour, i never had headphones with real leather but those are more expensive but i would like to try it

You should only do the above (complicated) test when you really want to find out if the differences are real and of electrical origin otherwise just use as is.
no im fine with that and it could be what you are saying it is, our brains are tricky and powerful, for example when someone go "hunt ghosts" they got so paranoid that they start seeing and hearing things or if they hear normal squeak they freak out

few days ago when i was sleeping and alarm clock went off, i turned it off and then fell asleep again a i had a dream that i woke up and was preparing for work and after 30 mins i woke up a realized my brain tricked me a i was a bit late for work this is the first time this happened to me, maybe it was because i was so tired from the other day that my brain wanted me to sleep a bit longer

btw balanced cable should arrive tomorrow or on monday if im reading the tracking of package correctly i mean "Presented to import Customs" so i dont know how long it will take to get to me but this should mean that its on the border of my country i guess
im very curious what the quality of the cable would be like and the sound difference if there will be any, if the quality would be good, is there some thread on this forum where is a list of recommended eshops for people from Europe? because its hard to get some stuff here in Europe

#### Spojkovic

##### Member
so balanced cable arrived and i can hear the difference in bass spectrum, when on SE it is weaker, thats the first difference i noticed right away, not mentioning volume of course

on balanced, bass is more powerful and more precise or how could i describe it, and maybe overall sound is a bit better but its hard to say cuz of volume difference, i would have to do the same what solderdude said about A50 vs A50s

#### DChenery

##### Active Member
Forum Donor
Obviously, this will get me banned, and I will probably burn in hell for all eternity, but maybe we should suck it up and state the obvious - your fearless leader actually has ears of cloth. No matter how hard you press it, these are the most measured and listened to headphones in the real world. Just cause somebody with beau-cope de bucks has awesome equipment, doesn't mean the reported results are even close to correct. While I am/was less politically correct than Solderdude, the message is the same - @amirm is kinda full of ... an incorrect evaluation.

Even I can hear the difference between the different HD''s. For reference, I will definitely be in for some horrid times when I expire (pop my clogs), as my real job is designing hydraulic fracture treatments and sand control measures for both oil amd gas wells

Debate.

#### MdeVelde

##### Member
For Windows users using 'Equalizer APO':

Sounds fairly rolled off to me in the treble.
Here Oratory1990's EQ preset (also based on measurements on a Gras system):
Sounds best to me of all EQ settings I could find (many to be found through AutoEQ).

#### Robin L

##### Major Contributor
Sounds fairly rolled off to me in the treble.
Here Oratory1990's EQ preset (also based on measurements on a Gras system):
Sounds best to me of all EQ settings I could find (many to be found through AutoEQ).
Looks a lot like my EQ. Gotta boost the top 4 octaves a little, or it sounds dim. Gotta really boost the bottom octave or it's just not there at all. Not ideal [the more the bottom octave gets boosted, the "looser" the bass sounds], but it's better than not having deep bass.

My Drop 6XX sounds fine on anything not requiring deep bass. This applies to most acoustic sounds.

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#### MdeVelde

##### Member
Looks a lot like my EQ. Gotta boost the top 4 octaves a little, or it sounds dim. Gotta really boost the bottom octave or it's just not there at all. Not ideal [the more the bottom octave gets boosted, the "looser" the bass sounds], but its better than not having deep bass.

My Drop 6XX sounds fine on anything not requiring deep bass. This applies to most acoustic sounds.
The Drop 6xx is identical to the HD650 right?
For my HD650 my close second choice for my EQ is the Innerfidelity HD6xx EQ through AutoEQ. (strange enough the Oratory1990 HD650 EQ must be done manually through Oratory1990's HD650 settings as the AutoEQ version doesn't sound as good to me).

I think after EQ the deep bass on my HD650 sound fine for a headphone btw, at not too high listening levels. Allows me to really enjoy some bass heavy electronic music.
Was just playing this:

And it can half-decently pull off this. Though no headphone can do it real justice, it needs to be felt through your whole body

#### Robbo99999

##### Major Contributor
Forum Donor
The Drop 6xx is identical to the HD650 right?
For my HD650 my close second choice for my EQ is the Innerfidelity HD6xx EQ through AutoEQ. (strange enough the Oratory1990 HD650 EQ must be done manually through Oratory1990's HD650 settings as the AutoEQ version doesn't sound as good to me).

I think after EQ the deep bass on my HD650 sound fine for a headphone btw, at not too high listening levels. Allows me to really enjoy some bass heavy electronic music.
Was just playing this:

And it can half-decently pull off this. Though no headphone can do it real justice, it needs to be felt through your whole body
Ha, yeah, at 30 seconds and 1min etc, etc, wow! (on the second one)

EDIT: also tested it on my JBL 308p speakers, and yes, it's like a wave rushing over you at loud volumes! My headphones with EQ can go lower, but the overall effect is about the same when taking the body feel effects of the bass from the 308p speakers.

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#### peniku8

##### Active Member
I built a headphone measurement fixture to measure channel imbalance with. Here are my results for my HD650:

I took 3 measurements of the left side and the same count of the right earphone. I removed the headphones from the fixture between measurements to iron out possible positioning errors. Channel matching looks exceptional to me

#### Robbo99999

##### Major Contributor
Forum Donor
I built a headphone measurement fixture to measure channel imbalance with. Here are my results for my HD650:

I took 3 measurements of the left side and the same count of the right earphone. I removed the headphones from the fixture between measurements to iron out possible positioning errors. Channel matching looks exceptional to me
That does look exceedingly good for channel matching. You might not be able to use the frequency response measurements for that much else, but I think it's pretty valid to check channel matching.

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