Pre-amp and Headphone amplifier separates? - Page 2

And I've seen CD setups with dedicated monoblocks... what's your point?

It's not like vinyl means it's less worthy of quality amplification. In fact phono cartridges are balanced by nature and there are quite a few balanced phono stages on the market, so why not run it through the same balanced monoblock setup as other people do?

Really, after all the “real” crosstalk generated by the stylus your going to bother spitting the power amp channels into separate boxes?

Really, this is very similar to the cable debate. Some people hear a difference, others don't. I heard a pretty big improvement between a dual mono (two monoblocks in one case, separate power supplies, separate power cables) and monoblock version of the identical amp when they were separated into different cases. This was a SACD rig, but still, the point is that some people can see value in doing things in a different way regardless of what supposedly should happen.

Crosstalk is a quantitative audio spec, measurable, unlike cables. But yes we can turn this into a subjective hearing debate and get nowhere.

Professionals in studios use very flat sounding active monitors rather than fun and musical speakers. I'd also like to see you try to integrate a quality, high current capable, amp into a planar speaker that is all of 2" thick. You can give me the crappy class D argument all day, but I have yet to hear a class D amp come close to even a class B amp, which is already subject to a sometimes audible crossover point in the amplification process.

And I really wouldn't call the people that have been tweaking their speaker rigs for years and years amateurs. I know quite a few such people running amps weighing in a a couple hundred pounds, good luck fitting it into any of these amazing speakers you have.

 

Some headphone amps have L/R outputs for hooking up to a separate power amp.  Therefore, the headphone amp is now essentially a preamp.  Get a dac and now you're running separates.

 

I guess this would be the closest thing to what you're asking.  I haven't tried it myself and now you've got me thinking about it since I'm an advocate of non-integrated components.

Perhaps a flea powered tube amp would fit the bill but even that would be quite risky and would be harmful to the headphone don't you think?

 

I just wish that all the higher end preamp makers would add a quality headphone output jack for us headphone lovers

Edited by vinyl addict - 8/11/12 at 2:15am

What's going to harm it? It's not really any different than taking a headphone amp and turning it all the way up. Too much power is too much power, keep your levels lower and there's no issue. It would be more risky for the amp than the headphones in that scenario as the tube amp likely has OPTs that do not have, for example, 32Ω secondaries so you would be presenting an odd load and it would be highly strained to output it. A SS amp, or an OTL amp would be your best bet if you wanted to run a speaker power amp for your headphones.

You can run a tube amp with OPTs on any load above their ratings, but you have to do some dummy loading along with your headphones or speakers to keep them running normally. That's not really hard to do, but you can't simply connect your 600Ω headphones to a 8Ω secondary and expect it to work properly, if at all. SS and OTL is just easier to do for headphones with widely varying impedances.

I agree with a lot of johnwmclean's arguments and explanations (especially regarding grounds and so on) - a lot of the separate/etc (be it active multi-amplification from a studio, or hi-fi audiophile monoblocks and all that) designs and plans are irrelevant or otherwise inapplicable to headphones. Generally there's also the consideration of value in so-called "dedicated headphone amplifiers" - this is not to say that all of them are garbage, but many of them are insanely priced relative to what's inside of them (and don't talk to me about R&D or some other fantasy land explanation to justify 80-90% mark-up), so that should be considered as well. It's still very much an "accessories" industry except at the extreme high end and the entry-level or non-audiophile (e.g. a lot of stuff for computer gaming that also functions as a headphone amp, and those are generally competent components at that). Again, this is highly variable, but worth considering when you go off to buy new equipment.

I don't get the argument that headphones are completely different from speakers. I see no difference between a headphone and a full range speaker, really, at least when it comes to amplification. The only difference to cite is an unbalanced wiring scheme... if we assume everyone is using a TRS or some other unbalanced connector. First thing you balance your headphones, you are back to the equivalent of speakers again.

As far as the common ground issue goes, what happened to the whole path of least resistance thing? The path through the grounds between components will have higher resistance than that of the grounds within the amps themselves simply due to the distance from one amp to the next regardless of your home wiring or power cable wire gauge, therefore a natural tendency to not interact with each other to, at the very least, a minimal extent. The ground they share, if properly done, is also behind a significant amount of filtering if your amplification has a half decent design, so any noise involved in your ground from the power should be blocked out by that as your power supply should be well isolated from your signal and amplification anyway. Having individual filters and supplies for each amplifier board should filter this ground noise out from one channel to the next.

I'm simply trying to say that there are potential benefits to doing this, and measurable ones for those of you that refuse to listen to an argument unless it's got some numbers in it, and you can't dismiss it as useless and irrelevant simply because it can be overpriced, and it can be just as bad, if not worse, than what you already have.

The monoblock concept has merits for high power speaker amps rather than headphone amps due to the large currents involved. Besides the placement of the power amp close to the speakers, to minimise the length of speaker cable, they usually have much larger transformers, and are located away from the pre-amp with little chance of inducing hum/noise into the small-signal circuitry. Each monoblock amp has a separate power supply and ground which are not shared anywhere except at the input common ground (through the interconnect cable, where there is miniscule current). Allows for maximum channel separation. Of course a dual-mono construction in a single chassis could be made to do this, but chassis grounding needs to be common in the latter case.

I think many use monoblocks just because generally they have more power output than one chassis amps. I have heard the crosstalk argument too but am not in a position to comment since I don't use monoblocks. But it is the first time I hear people use monos because they want to use shorter speaker cables ... Well... Not sure if that is valid because shortening the distance between the monos and the speakers would mean the necessary lengthening of the signal cables between the preamp and the monos.

Anyway I think the topic is on whether preamps would help with the sound of headphones rather than monoblocks vs one chassis.
Edited by googleli - 8/12/12 at 10:37am

I don't even use a preamp. I power my HE-6 directly from the speaker terminals of my tube amplifier, 60wpc.

My source is an Oppo BDP-95, it has variable output.

 

Reportedly sensitive headphones can pick up a bit of hum from a noisy speaker amp, though there are plenty of speaker amps on the market which work fine like the First Watt units.  I've heard hum on the HD800 through multiple headamps, so it's not just a speaker amp thing.

 

Aside from the HE6 outlier, I'm not sure why preamps and speaker amps are dismissed among headphone enthusiasts.

 

I think I'm going to make a 4-pin XLR male to 1/4" female plug to try driving other headphones off the J2 to see if it's missing something.

 

Your preamp needs very low output impedance, and the ability to drive long capacitive interconnect cables without ill effects. Forget unbuffered or passive pre-amps. 

 

 

Given that most high end interconnects are only 1.5m to 2m, while speaker cables typically go at least 8 feet, I am not sure whether this is the intended / desired setup for monoblock systems.