[Xenophon]

  I think there is some confusion with the new vs old amps.  Visually it seems like the new amps have yellow la figaro writing/logos while the old one has silver.  Internally the new one has the upgraded resistor array and some other new components.  As mentioned in this thread previously, the new amp should be able to run the 6C5 but the "new" la figaro amp that I have seems to be wired conventionally even though it looks like the new version on the outside and internally (with the new resistor array).  I did purchase the "new" version from an ebay store, but it didn't sound like these guys modified the old conventionally wired version and then just re-sold.  They simply seemed like resellers.  When I purchased my EF86 adapters from yuking/la figaro they requested a picture of the internals of my amp.  I think they wanted to make sure it was the "new" version, and once they saw it, sent me the EF86 adapters.    
 
At one point I tried to clarify (in Chinese) what tubes could be used with both new and old versions of the amp but I never received a response from la figaro.  
 
Maybe there are two different "new" versions of the amp in the wild.  

That would not surprise me in the least, history repeats itself.  I'm very happy with the product quality, couldn't be better imo and superior to some so-called 'western' amps going at 4 times the price (own a 337) but they should get their act together on versioning and modifications. even if most customers won't be bothered with the internals. 

 

[MJS242]

   
How confusing.
 
Other than tubes, is there much sonic difference between the "old" and "new" versions? Or are they quite similar?

 
I'm not definitively saying there are two "new" versions out there, but there seems to be some confusion and I'd hate to see someone try to use a 6C5 in the wrong amp because I don't know what the end result would be.  In terms of sonic differences between the two, I would say the new one sounds slightly more nuanced if that can make any sense at all.  Bear in mind, I'm not skilled at doing comparisons like this.  My appreciation for a system is more about an overall feeling/intimacy and less about small details. IMO, all anyone needs to know about the new and the old is that they both sound great.  My take may be on the new and old conventionally wired 339 though.  Here is the pic of the inside of my new one, if you can take one, maybe we can compare:
 

 

[Ultrainferno]

   
I'm not definitively saying there are two "new" versions out there, but there seems to be some confusion and I'd hate to see someone try to use a 6C5 in the wrong amp because I don't know what the end result would be.  In terms of sonic differences between the two, I would say the new one sounds slightly more nuanced if that can make any sense at all.  Bear in mind, I'm not skilled at doing comparisons like this.  My appreciation for a system is more about an overall feeling/intimacy and less about small details. IMO, all anyone needs to know about the new and the old is that they both sound great.  My take may be on the new and old conventionally wired 339 though.  Here is the pic of the inside of my new one, if you can take one, maybe we can compare:
 

 
1st Gen:
 

 

[White Lotus]

It's all so clean and neat.

 

[Xenophon]

  It's all so clean and neat.

You know, this is what convinced me to purchase my 337 (used):  a company paying attention to stuff like clean wiring, soldering etc -elements not immediately visible to the user- is indicative for a type of mindset that goes with the pursuit of excellence.  I'll take that any time over a fancy case.  Have seen tube amps from 'premium' western companies (but also made in China though they try to fudge that) that were really a disgrace once you looked under the hood.  And they sell at >5 times the price of the DV amps.

 

[xmdkq]

Transform 339

 

[Xenophon]

Gorgeous!  What are the exact mods for resistors and caps?
 
Bet those GEC tubes sound nice, not too affordable though (been on the lookout for 6AS7 GEC's for my 337)

 

[Ultrainferno]

the GEC 6080 ain't too expensive though and easily available

 

[Xenophon]

  the GEC 6080 ain't too expensive though and easily available

Any tips as to good online stores, preferably in the EU?

 

[MJS242]

  Gorgeous!  What are the exact mods for resistors and caps?
 
Bet those GEC tubes sound nice, not too affordable though (been on the lookout for 6AS7 GEC's for my 337)

 
You're looking at the 6C5C, 6J5, 6J5G, 6J5GT, CV1067, L63 version of the 339 which I believe he made custom for a friend.  I've been talking to the boss a little bit, and it sounds like the "new" 339's you can get now from their website or ebay are the conventionally wired 339 (with upgraded components), so 6J4P,6AC7,6SJ7.  
 
Here is a recent post on it:
 
http://www.diybuy.net/thread-911791-1-1.html

 

[Ultrainferno]

source = ebay or the usual US sellers

 

[kramer5150]

+1 on the DV / Figaro PTP component layouts and internal build quality.  I think its unmatched for the $$, and I think its a hidden strength of the DV/LF amps.  Some of the latter 337 models had severely under-spec'd power resistors that were smoking.  Mine is the older model with green ceramic resistors... a GREAT sounding circuit.
 
I modded mine with output transformers and it sounds great with all my RS1 and K701.  I have HD650 drivers incoming tomorrow for my HD600 and will get to test it out with those.  With output transformer coupling its basically a ~1.5 watt speaker amp.  I could (quietly) power pair of 8 ohm speakers with it... and the tubes would still "see" impedance loads north of ~6-700 ohms.
 
The other cool thing about OTs is they block DC, so for me its additional peace of mind and safety for my cans.  I smoked my HD580 drives with DC oscillation with my PPA... not a pleasant experience.

 

[dante020]

  +1 on the DV / Figaro PTP component layouts and internal build quality.  I think its unmatched for the $$, and I think its a hidden strength of the DV/LF amps.  Some of the latter 337 models had severely under-spec'd power resistors that were smoking.  Mine is the older model with green ceramic resistors... a GREAT sounding circuit.
 
I modded mine with output transformers and it sounds great with all my RS1 and K701.  I have HD650 drivers incoming tomorrow for my HD600 and will get to test it out with those.  With output transformer coupling its basically a ~1.5 watt speaker amp.  I could (quietly) power pair of 8 ohm speakers with it... and the tubes would still "see" impedance loads north of ~6-700 ohms.
 
The other cool thing about OTs is they block DC, so for me its additional peace of mind and safety for my cans.  I smoked my HD580 drives with DC oscillation with my PPA... not a pleasant experience.

Any more information on exactly what you did with the output transformers? Internally/externally mounted? Pics? I have a Bottlehead Crack and LF339 and I'd like to try and drive some low impedance phones but they don't sound great (unsurprisingly). Thanks!

 

[kramer5150]

I tried to mount them inside the 337 chassis and keep the great sounding 400V-51ufd paper-film coupling caps... but there's no room for both.  With the 6AS7G it pretty much needs either a large capacitance bank or large "iron" in order to power low impedance loads.  I could have switched to electrolytic capacitors which are WAY smaller, but at ~400V... I couldn't find any that at least were reputed to be as good sounding for an application like this.
 

 
 
 So I run them externally in a separate enclosure, a kind of semi-mod if you will.
 

 
Looks like a rats nest inside, but those are all the optional secondary coil taps, most of which I don't use.  They are just heat shrink insulated inside.  I can't remember the specifics, but I think these are rated for ~20 watts.  Of course with headphone wattage thats way over-spec, but the key is to intentionally over-spec the transformer... and keep it operating in a range where it outputs the full spectrum from 20-20k.  For most OTs, the less AC wattage they receive on the primary... the broader their frequency response is out the secondary.  I have never tried a higher wattage transformer, but like anything else I would guess theres a point of diminishing return.  I don't even know if you could use a 50-100 watt OT, with headphone milliwatt power.  It might not even be enough to properly "energize" the primary coil.

 
A cleaner, but slightly more $$$ solution would be to use the Hammond 119DA that Mapletree uses in their amps.  But it only has two secondary coils.   I wanted more so  I could pick and chose whichever one sounds best with my amps. Not shown in the pics, I have since added a dual pole ON-OFF-ON switch so I can switch between two different secondary coils, with the middle OFF position being the same thing as unplugging the cans.
 
With speaker amps and guitar amps the OTs need to have a load on the secondary coil.  Supposedly very bad things happen when you turn up a guitar amp with no cabinet plugged in.  I am not sure why this doesn't happen in headphone-land... but I am glad it all works.  I have NEVER read about a mad ear+ blowing up its hammond OTs (for example).
 
On a side note... my earmax sounds terrible with OT coupling.  Its really stale, flat, cold.   like a bad solid state amp.  Like it had the life sucked out of it.  if you can imagine difference between the HD600 and HD280.  So... OTs I think only work well with some tubes.

 

[MJS242]

Anyone else running EF86 tubes with the 6Ж4С/6SJ7 adapter? I just started using them today with two TFK EF86's and RCA 6AS7Gs.  Very nice sounding tube.