New! HeadRoom Desktop Balanced Amp! - Page 9  

WooHoo!

I was wondering about those myself...combo jacks, cool. They have the same ones on the front of the Meier Opera, not the same though.

*Adding this and the Rudistor to my short list of affordable balanced amps.

I was under the impression that you can not ballance a stock single ended headphone cable because there is not enough wires in a stock type cable.

The HeadRoom Desktop Balanced Amp is officially for sale!

oh sweet jesus.

oh.... no.... uh, anyone seen my wallet. last i saw it, it was running screaming down the street.

Hi Mark,

Sorry I didn't answer your question sooner. Both the AKG K701 and Sennheiser HD650 have two wires going to each driver and those wires go all the way back to the headphone plug. One goes to the + side of the driver and the other to the - side. The ones connecting to the - side are both terminated to the sleeve of the headphone plug and often refered to as ground. The vast majority of other headphones have only one wire that is connected to the sleeve and this usually gets a split either at the Y if its a dual sided headphone or in the earpiece with those that have single sided termination. So, if I cut off the 1/4" plug leaving the rest of the cable intact with the headphone, I will have four wires available.

But, XLR's have three pins on them. In the recording studio environment things like microphones and the associated cables as well as tape recorders etc. use all three pins. They are usually terminated with pin one being the shield of the cable, again sometimes refered to as ground. Pin 2 is + and pin 3 is -. The shield helps protect the signal from various electrical noise and the balanced signal further helps with its ability to cancel noise as well. When we get to the output for a headphone, the shield doesn't have anything to connect to like a chassis of an amp or the ground plane of a circuit board where the noise could then return to earth. Further, many would say that it's not really necessary because of the way that balanced drive works. On our Fat Pipe upgraded headphones, we go ahead and connect the shield to pin 1 just to keep the voodoo out and also to help keep the cable integrity in tact. Also, we're paying for the metal anyway so we might as well use it right?

I hope this helps. If you have any further questions, let me know. Some information that may help in understanding more can be found on our balanced headphone articles

Cheers,
Jamey

Yes it did.

This was an example of the finest customer service in the business. I mean it thanks.

It took a while but here you go:


I think this product will be $99 including the balanced to 1/4" adaptor. Comments or questions are much appreciated.

Cheers,
Jamey

Very nice, Jamey.

One other thing to maybe consider are female-to-female XLR gender converters because some balanced outs are male (I'm thinking of my DAC1). Not sure if there would be enough demand, so perhaps people could chime in here.

EDIT: or just a choice of female XLR terminations on the cable itself. Whichever is easier and more cost-effective all around.

In my opinion it's a heck of a deal especially with the adapter included! I bet you sell them in bunches.

x2. This is a very attractive deal; great savings to me the customer.

Very good value indeed. Especially considering the raw parts costs involved. Perhaps you could offer and equivalent service for the 880 and 701's, i.e. just a simple retermination job with an adapter, also for $99.

First impressions of the Prototype (I've long since returned it to HeadRoom, but I wrote these comments at the time):

Differences from other HeadRoom amps:

No filter switch (treble boost, 3dB from 1.5k or 3k) - no room for one on the board.

Power switch on rear panel.

No dedicated preamp outputs (though as the headphone outputs are XLR, there is no disadvantage to using those as outputs with the required m/f adapters).

No dedicated unbalanced signal path - the unbalanced connectors are fed through the line driver stage which adds some background noise to the signal (more on that later). To get a completely clean signal path for single ended headphones, the balanced inputs need to be used.

General usage notes:

Particularly when placed directly ontop of the DPS which itself can get somewhat toasty, the amps runs hot - it's not hard to see why they felt that Max Modules would be too unreliable as they put out consideraby more heat. Even when standing in free air outside the convertible, the Max's are too hot to touch.

The stepped attenuator has a very different attenuation curve to the pots in the other HR amps. At the low end, the steps are very small, and at the high end the steps are very large. This gives you excellent fine control of the volume, however requires that you optimise the gain setting to keep you in the bottom half of the SA's range. In my use, this means that I tend to have the gain set higher for the same given volume level, relative to what I might think was optimal with a pot.

The silly part:

The balanced iPod test. This was a real shock. Placebo or not, it sounds darn good. I have been using the iPod as a source a lot recently, fed into my convertible running Max Modules. This Desktop has only the Home Modules, but sounds at least as good and in some ways better than that setup. With 650's, the difference immediately strikes you in the bass response, which is more visceral yet at the same time more defined and tuneful - the fundamental tone is somehow more audible, with less general mud. The down side of the unbalanced signal path is that the line driver does add some background hiss to the signal. Combined with the iPod's low 1V output, the unbalanced input isn't really that great if you are using unbalanced cans, as the noise is at the same level but the gain is 6dB lower and therefore the voume setting 6dB higher. Used in the context it's designed for, i.e. with balanced cans, the hiss is inaudible at normal listening levels, and you have to turn the volume up all the way to full power with a silent background to hear a hint of it. Remember this is a worst case scenario due to the low 1V input from the iPod. A source with a standard 2V output would give you another 6dB of S:N. [Caveat: this unit was a prototype with some finnicky wiring and ground planes, and had some issues with hiss and buzz anyway depending on various factors, so I suspect the shipping unit will be better in this regard]

Would you want to run unbalanced sources through the balanced driver? You are getting a trade-off. You get a small degradation of the original signal, however you also give the amplifier increased control over the headphone, particularly noticeable in the lower frequencies. I'd say in this case it's a wash, and depends on what sonic aspects are most important to you.

The serious part:

The Home Balanced DAC test. This is really what this amp seems to be designed for - a 1 (or 2) box fully balanced digital source and amp. There's still a big debate about whether there are technically any real benefits from balanced drive, versus for example 3 channel topologies found in some DIY designs. There's no point getting into that debate here, as what is clear is that each set of electronics reacts differently.

In the case of the HeadRoom Module designs, they do take on a greater level of authority when put together as balanced pairs, and when the signal path is as pure as it would be in a purely single ended design, what's there to lose except cash from your wallet? Whether it's a matter of simply having double the power output, reduction of crosstalk or neither of the above, there is a greater sense of presence. It's slightly smoother but yet less laid back at the same time if that's possible. What's odd about this setup is that it seems to have a greater sonic purity compared to my convertible setup. If this was a single ended comparison, I wouldn't hesitate to say that the Max Modules have a 'purer' sound than the Home Modules which are relatively euphonic, so it's odd to find that the change in drive scheme can clean up the sound the way it does.

I'm greatly enjoying having a stepped attenuator, which every time I come back to one I always say is the only way to go. Whatever config, whatever amp, if there's a SA option, get it. I think particularly for balanced drive where there are now 4 channels to match, it's a must.

Cosmetic oddities:

The front panel looks ever so slightly strange in that the volume control and switches are lower than they would be on a normal Desktop, leaving a lot of empty space above. This was as far as I can tell necessary, as the main board has to be placed on a lower rung to make room for the secondary board that houses the filter caps and DAC board.

The switches, in being 4 channel switches are nice and chunky, which I rather like. They feel solid when you flip them. Irrelevant but nice.


HeadRoom Desktop w/Max Modules, Max DAC and Stepped Attenuator + DPS: $1895

HeadRoom Balanced Desktop w/Home Modules, Home DAC and Stepped Attenuator + DPS: $2095.

That's $200 more, and you are giving up dedicated preamp functionality (which these amps do extremely well in my experience), as well as a measure of headphone and input flexiblity, and you also no longer have a pure single ended signal path. It's a case where people will just have to listen for themselves to see what this balanced thing is all about. If you are convinced that balance drive is the way to go, then the Balanced Desktop it is, but if you aren't so sure, you can get an amp from HeadRoom that has higher end electronics in both the DAC and amp for $200 less.

nice review thingy!

wonder when people will be getting them in their hands? fw days if most maybe?


cant wait to see the impressions