[R Giskard]

Not to be hijacking the thread or anything but to those that are experiencing hiss through their headphones. This is a perfectly normal thing.You have to consider that the nominal impedance of headphones is not the same and changes with frequency, hence the impedance is emasured at 1Khz. It can drop below that at which point it may present a problem for the amplifier. 8dB feedback would resolve the matter easily but would certainly change the frequency characteristics of the amplifier. Hiss is a far more acceptacble thing than compromised dynamics and that's exactly what would happen otherwise. Solid state amplifiers are less sensitive to feedback than tube amplifiers but even this seems to have been too much for SPL. Let me give ne example, the WA2 and WA3 amplifiers are miniature compared to my reference amplifier. It took twin 250VA power transformers, 5 RC filters per channel, AC heating and substantial power capacitors to lower the output impedance to 32 Ohm. When hooked up to 32 Ohm load, there is some residual hiss. The instruments show it and it is supported by theory. It is the same thing with SPL amplifier in question, it appears to me SPL might be one of those companies that still operates on the engineering principles rather than on marketing and outrageous claims, like the 8 Ohm driving ability of the Woo Audio amplifiers. They can drive such loads yes, but at significant cost in audio quality. One ther thing, feedback will enable use of less parts and this is especially true when it comes to filtering section which is the most important and most expensive part in any amplifier. It seems I have something against Woo Audio and that would not be true, I am just commenting on what I see and hear.

 

[dukeskd]

Quote:

Not to be hijacking the thread or anything but to those that are experiencing hiss through their headphones. This is a perfectly normal thing.You have to consider that the nominal impedance of headphones is not the same and changes with frequency, hence the impedance is emasured at 1Khz. It can drop below that at which point it may present a problem for the amplifier. 8dB feedback would resolve the matter easily but would certainly change the frequency characteristics of the amplifier. Hiss is a far more acceptacble thing than compromised dynamics and that's exactly what would happen otherwise. Solid state amplifiers are less sensitive to feedback than tube amplifiers but even this seems to have been too much for SPL. Let me give ne example, the WA2 and WA3 amplifiers are miniature compared to my reference amplifier. It took twin 250VA power transformers, 5 RC filters per channel, AC heating and substantial power capacitors to lower the output impedance to 32 Ohm. When hooked up to 32 Ohm load, there is some residual hiss. The instruments show it and it is supported by theory. It is the same thing with SPL amplifier in question, it appears to me SPL might be one of those companies that still operates on the engineering principles rather than on marketing and outrageous claims, like the 8 Ohm driving ability of the Woo Audio amplifiers. They can drive such loads yes, but at significant cost in audio quality. One ther thing, feedback will enable use of less parts and this is especially true when it comes to filtering section which is the most important and most expensive part in any amplifier. It seems I have something against Woo Audio and that would not be true, I am just commenting on what I see and hear.

I know its normal but with the DacMini there is completely no hiss at any point in the volume or at any impedence. I think that's good stuff!

 

[R Giskard]

Most manufacturers make certain compromises in order to make the product more appropriate for general public. With amplifiers it's usually a paramount to make it completely silent, as you've noted, at any volume and gain setting. To a large majority of people this will be more important than to have a wider dynamic range for example. After all, everyone can hear hiss and not everyone can distinguish a difference between a lower quality and higher quality amplifier.

 

[dukeskd]

Quote:

Most manufacturers make certain compromises in order to make the product more appropriate for general public. With amplifiers it's usually a paramount to make it completely silent, as you've noted, at any volume and gain setting. To a large majority of people this will be more important than to have a wider dynamic range for example. After all, everyone can hear hiss and not everyone can distinguish a difference between a lower quality and higher quality amplifier.

For me, the hiss really, really, aggrevates me especially when I am producing music. That's why Dacmini is highly recommended for producers/musicians because dead silence and high quality sound is a necessity in those environments. But you are right that a hiss doesn't necessary means the amp is of low quality but it would help to make it silent, because I think audiophiles and musicians alike want to hear a clear record of the music.

 

[R Giskard]

Well, it's one of the reasons I use 300 or 600 Ohm headphones for usual studio work. I am not familiar with the Dacmini you are referring to so I cannot comment on that. If it wounds good to you and you feel like what you are hearing through it translates well to your recordings, then that's all that really matters.

 

[dukeskd]

Quote:

Well, it's one of the reasons I use 300 or 600 Ohm headphones for usual studio work. I am not familiar with the Dacmini you are referring to so I cannot comment on that. If it wounds good to you and you feel like what you are hearing through it translates well to your recordings, then that's all that really matters.

Yeah, I know that the Auditor is also great for studio work because of its neutrality but IMO, the O2 would work better and at a lower price especially matching the neutrality of the amps.

 

[HaVoC-28]

Quote:

Yeah, I know that the Auditor is also great for studio work because of its neutrality but IMO, the O2 would work better and at a lower price especially matching the neutrality of the amps.

 
Have you compared Auditor and O2 ?

 

[dukeskd]

Quote:

 
Have you compared Auditor and O2 ?

I haven't bought them but tried the Auditor at a store and my friend owns an O2, not much discerning difference, but I believe the Auditor adds more "coldness" to the sound. A similar situation to the Matrix M-Stage and the Lehhman Black Cube

 

[R Giskard]

"O2"? I realize people are using contractions but since I'm not really all that into currently available kits, I cannot say I know what  you are referring to. I wouldn't call the SPL amplifier necessarily neutral or flat to the extrme. There are other amplifiers that have better linearity, that is rue. What I found about SPL that I like, and not just their headphone amplifiers, the general easy on the ears approach so to speak. In a long term session, it can be of great use. What they refer to as a 120 Volt technology is an old theory really and one that is no longer available. It was derived from solid state audio components that had a rather high internal volatege, such as the Yamah B1 and B2 amplifiers and Sony's early 1980s amplifiers with V-FET. These transistors are no longer manufactured due to extreme cost but to this date they remain the best iof the breed with all the advantages of transforme-less tube amplifiers such as the immense linearity and harmonic oscillation but with none of the shortcomings such as hiss or current consumption. The SPL with their discrete operational amplifiers running at 120 Volts has a lot of that sound in it even though they are not linear to a fault. I don't own any SPL equip,emt though, I couldn't make it work with the current setup.

 

[HaVoC-28]

Quote:

"O2"? I realize people are using contractions but since I'm not really all that into currently available kits, I cannot say I know what  you are referring to. I wouldn't call the SPL amplifier necessarily neutral or flat to the extrme. There are other amplifiers that have better linearity, that is rue. What I found about SPL that I like, and not just their headphone amplifiers, the general easy on the ears approach so to speak. In a long term session, it can be of great use. What they refer to as a 120 Volt technology is an old theory really and one that is no longer available. It was derived from solid state audio components that had a rather high internal volatege, such as the Yamah B1 and B2 amplifiers and Sony's early 1980s amplifiers with V-FET. These transistors are no longer manufactured due to extreme cost but to this date they remain the best iof the breed with all the advantages of transforme-less tube amplifiers such as the immense linearity and harmonic oscillation but with none of the shortcomings such as hiss or current consumption. The SPL with their discrete operational amplifiers running at 120 Volts has a lot of that sound in it even though they are not linear to a fault. I don't own any SPL equip,emt though, I couldn't make it work with the current setup.

 
 
For SPL  :
 
http://spl.info/fileadmin/user_upload/anleitungen/english/Auditor_2911_BA_E.pdf
 
i don't know if their mesurement are correct or not but it seams not bad at all on neutrality / linearity 

, well i am very happy with auditor soo ^^ . 

 

[dukeskd]

Quote:

 
For SPL  :
 
http://spl.info/fileadmin/user_upload/anleitungen/english/Auditor_2911_BA_E.pdf
 
i don't know if their mesurement are correct or not but it seams not bad at all on neutrality / linearity 

, well i am very happy with auditor soo ^^ . 

I think its excellent at neutrality and linearity.

 

[suikodenii]

@ akatona: nice & interesting posts. Thanks!

 

[R Giskard]

Quote:

@ akatona: nice & interesting posts. Thanks!

You are welcome mate!

 

[R Giskard]

Interesting this about this SPL amplifier though is that the manual advises against connecting a TS (a mono 6.3mm) connector into the amplifier since it will cause short circuit and damage the circuitry. Interesting, interesting! So I suspect there's no output buffer of any kind in this amplifier which is a strange move, even though the right one from perspective of cleanest signal path. 

 

[dukeskd]

Quote:

Interesting this about this SPL amplifier though is that the manual advises against connecting a TS (a mono 6.3mm) connector into the amplifier since it will cause short circuit and damage the circuitry. Interesting, interesting! So I suspect there's no output buffer of any kind in this amplifier which is a strange move, even though the right one from perspective of cleanest signal path. 

Akatona, you take a look at the Violectric amps? Would love to hear your insight on them.