Sennheiser HD 598 and analog source

[darkblue94]

Why do you need an amp with 50 ohm phones?

Don't necessarily "need" an amp for the 598's but it is oh so sweet with it, sounds much better than off the headphone jack.

 

[archie2]

Don't necessarily "need" an amp for the 598's but it is oh so sweet with it, sounds much better than off the headphone jack.

Just out of curiosity how is this accomplished unless you add something in addition to amplification, like a DAC. I have a set of AKG 240, the original Austrian made 600 ohm that I can see would benefit from a headphone amp but the rest of my phones run 32-50 ohms. I also have the Sennheiser HD598. I can run my phones through a Yamaha CR2020, Altec 345A tube and Pilot 240 tube with good amplification. My computer has Realtek audio technology which is no great shakes as far as I can hear. For portability I can run my phones through a tiny Maceton 4.1 with lossless APT-X BT amp and dac combo which sounds good to me. I sometimes use the Fiios EO6 which helps with my AKG 600 ohm but does little for the 32-50 ohm phones. If a good dedicated headphone amp would significantly improve my 32-50 ohm phones I'd be interested. I've read the pros and cons on this issue but am interested what AK members have to say on the subject.

 

[darkblue94]

Just out of curiosity how is this accomplished unless you add something in addition to amplification, like a DAC. I have a set of AKG 240, the original Austrian made 600 ohm that I can see would benefit from a headphone amp but the rest of my phones run 32-50 ohms. I also have the Sennheiser HD598. I can run my phones through a Yamaha CR2020, Altec 345A tube and Pilot 240 tube with good amplification. My computer has Realtek audio technology which is no great shakes as far as I can hear. For portability I can run my phones through a tiny Maceton 4.1 with lossless APT-X BT amp and dac combo which sounds good to me. I sometimes use the Fiios EO6 which helps with my AKG 600 ohm but does little for the 32-50 ohm phones. If a good dedicated headphone amp would significantly improve my 32-50 ohm phones I'd be interested. I've read the pros and cons on this issue but am interested what AK members have to say on the subject.

I'm guessing the confusion was with the comment "sounds much better than off the headphone jack." What I meant was it is better than using the headphone jack of the cd player as opposed to the analog RCA output jacks of the cd player to the analog RCA inputs of the headphone amplifier. The difference is not subtle.

 

[archie2]

I'm guessing the confusion was with the comment "sounds much better than off the headphone jack." What I meant was it is better than using the headphone jack of the cd player as opposed to the analog RCA output jacks of the cd player to the analog RCA inputs of the headphone amplifier. The difference is not subtle.

So if I streamed from a device through a dedicated headphone amp to my 32-50 ohm phones I would notice a marked difference? Maybe I'm dense but I get plenty of amplification from the devices at that level of resistance w/o external amps. There must be something else to make for such an improvement. Just trying to understand this.

 

[darkblue94]

So if I streamed from a device through a dedicated headphone amp to my 32-50 ohm phones I would notice a marked difference? Maybe I'm dense but I get plenty of amplification from the devices at that level of resistance w/o external amps. There must be something else to make for such an improvement. Just trying to understand this.

Yes, the difference is the tubes.

 

[archie2]

Yes, the difference is the tubes.

True, but unless you're prepared to pay big bucks for an all tube dedicated headphone amp what you'll get is a hybred. Tube pre-amp and SS output. There is some "tube effect" with the hybreds but it's minimal. I can detect a difference in sound from my Altec 345A 60 watt tube amp and Yamaha CR2020. Whether the difference is preferable or not depends upon the listener. Again, I'm dense. I think there must be something more than the minimal effect of a hybred amp if you're saying the tubes make the difference. Please have patience to bear with me. I'm guessing it's in the amplification circuit itself but really don't know.

 

[darkblue94]

True, but unless you're prepared to pay big bucks for an all tube dedicated headphone amp what you'll get is a hybred. Tube pre-amp and SS output. There is some "tube effect" with the hybreds but it's minimal. I can detect a difference in sound from my Altec 345A 60 watt tube amp and Yamaha CR2020. Whether the difference is preferable or not depends upon the listener. Again, I'm dense. I think there must be something more than the minimal effect of a hybred amp if you're saying the tubes make the difference. Please have patience to bear with me. I'm guessing it's in the amplification circuit itself but really don't know.

I have a Bottlehead Crack headphone amplifier with the Speedball circuit upgrade. I've got $400 invested in the amplifier and 5 hours assembly time. Not too high-end really and the basic kit is $299. It is not a hybrid amplifier at all, both sections are tubed. If not for it being a self assembly kit the finished product would retail in the $800 to $1000 price point.

 

[archie2]

I have a Bottlehead Crack headphone amplifier with the Speedball circuit upgrade. I've got $400 invested in the amplifier and 5 hours assembly time. Not too high-end really and the basic kit is $299. It is not a hybrid amplifier at all, both sections are tubed. If not for it being a self assembly kit the finished product would retail in the $800 to $1000 price point.

You are one of a few that shelled out big bucks for an all tube amp and if you like the tube sound I can see where it would upgrade your headphone sound. I can probably get a similar upgrade using a direct feed from my Altec 345A. Although I've not tried it, it might be an interesting project. But the merits of a less-than-all tube-amp to improve the sound of 32-50 ohm phones still is in question.

 

[darkblue94]

You are one of a few that shelled out big bucks for an all tube amp and if you like the tube sound I can see where it would upgrade your headphone sound. I can probably get a similar upgrade using a direct feed from my Altec 345A. Although I've not tried it, it might be an interesting project. But the merits of a less-than-all tube-amp to improve the sound of 32-50 ohm phones still is in question.

I don't really feel that $400 is "big bucks" but it is relative I know. Does your Altec tube amp have a headphone jack? If it does, how would you control the volume?

 

[archie2]

I don't really feel that $400 is "big bucks" but it is relative I know. Does your Altec tube amp have a headphone jack? If it does, how would you control the volume?

No $400. isn't big bucks. But if you bought it plug and play at $1000. that's big bucks. My Altec 345A has volume control knobs, one for each channel. Alternately I could go through my Carver C-5 pre-amp, or buy a tube pre-amp. Actually I have a tube pre-amp but never assembled it.

 

[darkblue94]

No $400. isn't big bucks. But if you bought it plug and play at $1000. that's big bucks. My Altec 345A has volume control knobs, one for each channel. Alternately I could go through my Carver C-5 pre-amp, or buy a tube pre-amp. Actually I have a tube pre-amp but never assembled it.

Looking at the 345A amplifier I don't see that it has a headphone jack, how are you planning to use your headphones with it?

 

[keilau]

So if I streamed from a device through a dedicated headphone amp to my 32-50 ohm phones I would notice a marked difference? Maybe I'm dense but I get plenty of amplification from the devices at that level of resistance w/o external amps. There must be something else to make for such an improvement. Just trying to understand this.

The answer is a definite "yes". The reasons are technically very basic on 2 issues.

1. Power drive capacity.
2. Output impedance and damping factor.

The Audio Technica AT-HA5000 spec is shown here for illustration. But you do not need to spend upward of $1000 to get good headphone sound.
http://www.audio-technica.com.hk/index.php?op=productdetails&pid=657&lang=eng

AT-HA5000 Specifications
Type: Class A operational amplifier
Load Impedance: 16 to 600 Ω
Sensitivity: 1.1V / 50 kΩ
Maximum Output Power

2,400 mW + 2,400 mW (16 Ω load)
1,200 mW + 1,200 mW (32 Ω load)
600 mW + 600 mW (64 Ω load)
65 mW + 65 mW (600 Ω load)​

Frequency Response: 5 ~ 200,000Hz (+0, -0.5 dB, at 100 mW output, 32Ω load)
Total Harmonic Distortion: 0.006％ (20 Hz-20 kHz, at 100 mW output, 32Ω load)
Channel Separation: 62 dB (20Hz -20 kHz, 32 Ω load)
Gain: 15 dB
Signal-To-Noise Ratio: 117dB
Output Impedance: 0.1 Ω​

A power amplifier is a constant voltage device, whether a speaker or a headphone amp. From the spec above, A 600 ohms phone needs only 0.065 watt, but a 32 ohms phone needs 1.2 Watt. It takes the large current drive capacity of a good headphone amp to maintain the dynamics range of the music for low Z headphones. It is not a sensitivity issue. The same 1.1 volt input drives the phone to the same loudness, but the low impedance draws a much larger current (power). You can hear marked distortion increase in loud passage if the headphone amplifier does not have the power capacity for low Z phones. (This is an analogy to many commercial power amplifier cannot drive under 4 ohms speakers well, but have no problem with 8 to 16 ohms ones. Many better amp advertise their "high current" capacity.)

The output impedance and damping factor issue is easier to understood and needs no addition explanation. Without proper damping, the bass sounds loose and rings. It you like the tube sound, it is important to get one with output transformers. Entry level OTL tube headphone amplifier has high output impedance. It may still sound sweet and musical in the midrange, but the bass control will not be there.

For many years, music lover does not take headphone seriously. But with the high end phones like the Audeze or top of the line Sennheiser and many others, the thinking is gradually changing. A headphone amp is no more than a smaller power amplifier (1-3 watts) driving higher impedance loads (16 to 1000 ohms). The basic principle of good design remains the same as speaker power amplifier.

The Sennheiser HD598 is not high end, but is one of the most neutral sounding phone in the under $200 range. The selection of amplification is a very personal choice. The best way to tell is to listen yourself. After you try a high current dedicated headphone amp with the Sennheiser HD598 and do not hear any improvement in sound, there is no reason to worry about it anymore. Just stick with what you already have. (You should have no problem with the 600 ohms AKG 240.)

 

[archie2]

Looking at the 345A amplifier I don't see that it has a headphone jack, how are you planning to use your headphones with it?

I can play the 345A through the Carver C-5 pre-amp that I have hooked to it. While it's not a direct feed as you point out the 345A has no phone out jacks, it's close. Or in the alternative I can assemble the tube pre-amp that's been sitting around for about 15 years waiting for my attention. My set up consists of a Pilot 240 tuber, a Yamaha CR-2020 SS, the 345A, and an Onyko TX-SR502 playable through Polk 10A or Wharfedale W70E connected via a series of Russound A-B2 amp switches and a Russound MM-6 speaker matched impedance switchbox. I can isolate any one or a combination of headphone outputs. But truth be told I listen mostly to streaming music via a number of portable devices via a Maceton BT 4.1 amp/dac. I would be interested in a stand alone phone amp ONLY if I thought it would markedly improve the sound through my phones and wouldn't break the bank. I'm talking here 32-50 ohm phones ( ATH M50x, AKG K240, Sennheiser HD598, Samson SR950, Sennheiser HD290 pro) I have an AKG 240 monitor 600 ohm phone that would benefit but that's the only one above 50 ohms. And because I'm cheap I wouldn't spent more than $100. for the amp. keilau's post above pretty much answers my question re; the benefits of a good amp for 32-50 ohm phones.

 

[archie2]

The answer is a definite "yes". The reasons are technically very basic on 2 issues.

1. Power drive capacity.
2. Output impedance and damping factor.

The Audio Technica AT-HA5000 spec is shown here for illustration. But you do not need to spend upward of $1000 to get good headphone sound.
http://www.audio-technica.com.hk/index.php?op=productdetails&pid=657&lang=eng

AT-HA5000 Specifications
Type: Class A operational amplifier
Load Impedance: 16 to 600 Ω
Sensitivity: 1.1V / 50 kΩ
Maximum Output Power

2,400 mW + 2,400 mW (16 Ω load)
1,200 mW + 1,200 mW (32 Ω load)
600 mW + 600 mW (64 Ω load)
65 mW + 65 mW (600 Ω load)​

Frequency Response: 5 ~ 200,000Hz (+0, -0.5 dB, at 100 mW output, 32Ω load)
Total Harmonic Distortion: 0.006％ (20 Hz-20 kHz, at 100 mW output, 32Ω load)
Channel Separation: 62 dB (20Hz -20 kHz, 32 Ω load)
Gain: 15 dB
Signal-To-Noise Ratio: 117dB
Output Impedance: 0.1 Ω​

A power amplifier is a constant voltage device, whether a speaker or a headphone amp. From the spec above, A 600 ohms phone needs only 0.065 watt, but a 32 ohms phone needs 1.2 Watt. It takes the large current drive capacity of a good headphone amp to maintain the dynamics range of the music for low Z headphones. It is not a sensitivity issue. The same 1.1 volt input drives the phone to the same loudness, but the low impedance draws a much larger current (power). You can hear marked distortion increase in loud passage if the headphone amplifier does not have the power capacity for low Z phones. (This is an analogy to many commercial power amplifier cannot drive under 4 ohms speakers well, but have no problem with 8 to 16 ohms ones. Many better amp advertise their "high current" capacity.)

The output impedance and damping factor issue is easier to understood and needs no addition explanation. Without proper damping, the bass sounds loose and rings. It you like the tube sound, it is important to get one with output transformers. Entry level OTL tube headphone amplifier has high output impedance. It may still sound sweet and musical in the midrange, but the bass control will not be there.

For many years, music lover does not take headphone seriously. But with the high end phones like the Audeze or top of the line Sennheiser and many others, the thinking is gradually changing. A headphone amp is no more than a smaller power amplifier (1-3 watts) driving higher impedance loads (16 to 1000 ohms). The basic principle of good design remains the same as speaker power amplifier.

The Sennheiser HD598 is not high end, but is one of the most neutral sounding phone in the under $200 range. The selection of amplification is a very personal choice. The best way to tell is to listen yourself. After you try a high current dedicated headphone amp with the Sennheiser HD598 and do not hear any improvement in sound, there is no reason to worry about it anymore. Just stick with what you already have. (You should have no problem with the 600 ohms AKG 240.)

Thanks for the info., it makes sense. I'm not looking for high end, just good sound. At 80 my hearing range is only from 30 Hz to 13000 Hz but I still hear the harmonics within that range. Problem I have is accessing amps for comparison. I don't think it's wise for me to trial and error amps from an online store. So I'm kind of in the "take your best shot" situation. I have the Fiio E6 which improves the sound somewhat in an OK sort of way.

 

[darkblue94]

I can play the 345A through the Carver C-5 pre-amp that I have hooked to it. Or in the alternative I can assemble the tube pre-amp that's been sitting around for about 15 years waiting for my attention. My set up consists of a Pilot 240 tuber, a Yamaha CR-2020 SS, the 345A, and an Onyko TX-SR502 playable through Polk 10A or Wharfedale W70E connected via a series of Russound A-B2 amp switches and a Russound MM-6 speaker matched impedance switchbox. I can isolate any one or a combination of headphone outputs. But truth be told I listen mostly to streaming music via a number of portable devices via a Maceton BT 4.1 amp/dac. I would be interested in a stand alone phone amp ONLY if I thought it would markedly improve the sound through my phones and wouldn't break the bank. I'm talking here 32-50 ohm phones ( ATH M50x, AKG K240, Sennheiser HD598, Samson SR950, Sennheiser HD290 pro) I have an AKG 240 monitor 600 ohm phone that would benefit but that's the only one above 50 ohms. And because I'm cheap I wouldn't spent more than $100. for the amp.

Okay I'm getting the picture now. If you use the headphone jack on the Carver preamp you would be removing the Altec tube amplifier from the chain. It appears to me that you should forget all about the tube headphone amplifier concept and search for another option that will prove satisfactory to you.

 

[keilau]

Thanks for the info., it makes sense. I'm not looking for high end, just good sound. At 80 my hearing range is only from 30 Hz to 13000 Hz but I still hear the harmonics within that range. .

Your hearing range is better than MOST people at age 50 and above. It is a wonderful gift you need to treasure.

Problem I have is accessing amps for comparison. I don't think it's wise for me to trial and error amps from an online store. So I'm kind of in the "take your best shot" situation. I have the Fiio E6 which improves the sound somewhat in an OK sort of way.

The Filo E6 is a portable amp spec for high impedance phone. You need something different for the Sennheiser HD598. There is no need to "trial and error". I am building one for the 598. There are a few options as shown at this Audio DIY forum:

http://www.diyaudio.com/forums/head...r-board-k2381-j407-mosfet-yuanjing-audio.html

There are better option than the one I picked. But they all work fine.

 

[archie2]

I looked at several headphone amps, and several "best" 5 headphone amps recommendations and decided to see if working with what I have would improve my cans listening pleasure. So I hooked up my HRT Music Streamer II to my PC, ran it through a Rockrok amp then tried it with a couple of my cans. The improvement in sound staging and sound was immediate and pronounced. Volume also increased dramatically, much more than I need and a tad too bassy for my tastes but still tight, not a deal breaker. Too detailed and a bit harsh for the ATH M50x but smoothed out nicely with the AKG K240's. Turned down the bass on the little Rockrok amp and now it's much better. No longer overly bassed or harsh on the ATH M50x's. Haven't tried my other phones yet. That HRT streamer makes non high end phones sound pretty good. It features full 24/96 Hi-Res capability and asynchronous data transfer protocol. It also overrides the computer's built-in DAC to provide improved audio reproduction of computer music files and streaming audio from internet radio and sites like Pandora and Spotify which I stream.

 

[archie2]

Okay I'm getting the picture now. If you use the headphone jack on the Carver preamp you would be removing the Altec tube amplifier from the chain. It appears to me that you should forget all about the tube headphone amplifier concept and search for another option that will prove satisfactory to you.

Yes, I wondered about that. I did find another option using a HRT Music Streamer II. See my later post above.

 

[archie2]

Your hearing range is better than MOST people at age 50 and above. It is a wonderful gift you need to treasure.



The Filo E6 is a portable amp spec for high impedance phone. You need something different for the Sennheiser HD598. There is no need to "trial and error". I am building one for the 598. There are a few options as shown at this Audio DIY forum:

http://www.diyaudio.com/forums/head...r-board-k2381-j407-mosfet-yuanjing-audio.html

There are better option than the one I picked. But they all work fine.

I'll take a look at your options. Yep, even at 80 I still hear pretty good which is the reason I still fiddle around with this hobby I've enjoyed since I was a teenager.