Is there a reason Doug doesn't participate in the ECP thread here? It's like he's going out of his way to not give his fans info.
There is an ecp thread? I didn't even know. Do you have a link? I'm not trying to ignore anyone, I just haven't seen it.
Where is the attenuator for the SS version? Was doug using a preamp or something to control the gain? Am I missing something here?
I am a fan of the headphone power amp concept - basically, for people with a DAC that has a volume control, or for people who are going to just drop the amp into a rack with a preamp, forgoing the volume control, and in some cases the input stage, can save considerable money and space. And it eliminates a component that may compromise sound quality. Really, I do this for myself since I build dozens of different amps and it is easier to not have to equip every one with a volume control for testing.
Here are a couple pics of the Ravenswood (DSHA4) built that way.
I think your DSHA-4 is likely slightly behind the Copenhagen SS according to Doug.
Definitely not. The Ravenswood has a slightly different sound signature than the Copenhagen, but I don't think it is a lesser amp. Ravenswood is a little more relaxed sounding, Copenhagen is more visceral. I like, and use, them both. I think many people would prefer the Ravenswood.
On that note, to clarify: Different price points has more to do with cost of parts, and time to build. Other than the DSHA2, these are all semi-bespoke and my pricing is more or less done on a cost+ basis. But I think they are all equal in quality, choosing one over the other depends upon needs (DSHA2 is not going to drive the Abyss) and sound preferences.
The basic rundown is that the Ravenswood (DSHA4) is a high power, transformer gain, differential amp that will drive anything.
The DSHA2 is small (though still surprisingly powerful) meant for most dynamic and planar phones, but they must be balanced as there are no output transformers. It is our lowest cost amp by a fair margin.
The Apsara is the spiritual successor to the L-2 - it uses the same driver stage as the Ravenswood but has a differential triode output stage.
And the Copenhagen comes in a variety of flavors. It is a differential cascode circuit. The Copenhagen-V uses a JFET/Pentode cascode and is mid-powered. The Copenhagen-s (small "s" not shown, but basically the same as the V version Purk posted) is basically the same circuit but uses a JFET/MOSFET cascode while the Copenhagen-S (big "S", not small "s") is a MOSFET/MOSFET cascode and is considerably more powerful. The various versions sound more alike than different.