Where can I buy a built Dynalo for $300?

There was a company offerin them for $300 earlier this year, but I couldn't find them the last time I looked. I think they might have bought the rancho.

Check the For Sale Forum. Dynalos turn up, as does the Gilmore Lite which is pretty much the same thing.

If you want to try building one, AMB stocks boards and chips. It's not that tough. Build a $20 CMoy first and then you'll have the skills. The nice thing about the Dynalo is that it can use a wallwart power supply. That lets you cut out a layer of complexity. You'll only need a hand drill to put it in a good case, too. Give it a try - you should be able to bring one in for $150 and 20-30 hours of work.

Once you finish a couple amps, you'll be able to go to the high end, cheap. If you want lots of tubes, balanced designs, DACs, whatever you want will be available to you for the price of parts, which is usually a 75% discount over commercial.

Uncle Erik, are you talking about the Sheer Audio HA006+ which is a dynalo going for around 300?

 

http://www.acoustic-fun.com/catalog/product_info.php?products_id=62

Yes, that's the one! Am glad to see it available - the Dynalo is one of my favorites and a great amp.

Dynalos/Gilmore Lites sometimes show up on the FS forums too.
 

The Dynalo was originally devised for Grado headphones, as it can output 1W @ 32 Ohms (which most Grados are spec'd at). This is sufficient for some high-impedance headphones as well, including the HD600 (as it scales back with increasing headphone impedance), but a 600 Ohm headphone (the DT880/600) would be tough. For high-impedance headphones like the ones you mention, I'd recommend a tube or hybrid amp, and the Crack would hence make more sense.

 

Btw, "A" is a unit of electrical current and "W" a unit of power - not the same thing. Current has to be multiplied by voltage to get power: I (current in amperes) * V (voltage in volts) = P (power in watts).

I haven't heard the Crack but I'm sure that'd be a fine-sounding setup.

you could read the headwize project article - it specifically mentions what to look at when increasing supply V

 

the other option is to build/find/have built the "dynamid" - a balanced output version - you will need balanced headphone cabling too

The HD600 is a relatively balanced-sounding headphone across the board and I thought it lacked in both bass & treble extension. Good headphone overall (very natural tonality on too) but I never got past its general lack of clarity (I owned it 3 times). I had the 250-Ohm DT880 at the same time as the HD600, which was substantially clearer and had a treble tilt, and maybe a bit more bass "oomph" than the HD600. Never heard the 600-Ohm DT880; I recall reading reports from several years ago that it sounded different than the 250-Ohm model.

I can vouch for the dynalo as a great choice for a HD6x0 amp. The dynalo has the ability to "de-veil" the HD6x0 better than any other amp I've listened to them on.

jcx gave good advice: If having a dynalo built, rather than buying one of the standardized versions, raising the PSU voltage and resetting the bias does good things for higher impedance cans.

My personal work rig is a dynamid driving a HD650. I have a lot of amps and am always looking to build more, so the choice is because I really like the combination.

Be warned that the dynalo is a brutally exposing amp. Some don't care for that much transparency.

Quoting from Kevin Gilmore's original article http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=gilmore3_prj.htm :

 

 

The amplifier's output is voltage limited (not current limited) because the second stage runs out of voltage swing - typically about 6V rms. For a 32 ohm load, the maximum output power is 1.125W (0.1875A). For a 300 ohm load such as the Sennheiser HD600, the maximum output power is 0.125W (0.02A). To increase the maximum output voltage to, say, 10V rms, try increasing the power supply to ±20VDC and change the 500 ohm resistors in the current sources/sinks to 600 ohms (or ±24VDC and 700 ohms - but careful not to fry the output transistors).

The bridged version will output 4.5W into the 32-ohm Grados and 0.5W into the 300-ohm Sennheiser HD600. At full blast, the amp does drop out of class A, but at levels that will fry your ears anyway.

 

I wouldn't worry about the power output unless you want to drive a K1000, K340 or HE-6. My dynalos have never been underpowered driving Senns or Grados. The more important difference between a dynalo and a tube amp (or between any two amps) is how they sound. It depends on personal preference. I currently have a balanced B22 and a balanced Dynamite that will smoke my dynamid on power output. I slightly prefer the sound of the dynamid with my HD650. I personally don't get very jazzed about OTL tube amps driving HD6x0 compared to a good SS amp. There are a lot of posts with the opposite opinion on tube amps though. 

Edited by bada bing - 9/10/11 at 11:17pm