[WALL-E]

Holly molly, this thread is busy like never before!!! good to see the LF&DV community grows in strength.

 
 
Telecaster,
My DK339 is upgraded to fixed bias, the first version of the DK339 was based on the original LF339. My present DK339 contain battery bias modification.
 
I would suggest you to do measurement with ARTA over RMAA, ARTA is real time spectrum analyzer.
You will need a True RMS DMM to calibrate the in/out of your sound card, the multimeter have to be at least True RMS to 400Hz but strongly suggest 1000Hz and over! (any cheap DMM even if say TrueRMS they are NOT!) My 2 old multimeter are not but I got for Christmas One who can handle all the frequency and much more, so my earlier graphs(arta not calibrated) more or less reliable, but very useful tool when you compare(the same setting in arta) before and after.

To measure the FR the calibration is not necessary.
very important! - to do proper measurement  u will needed LOAD and only amp with dummy load resistor show how good or bad the amp is. I tell u why....running the test with the dummy load resistor, the impedance is not changing with increasing frequency (is constant), but some people used headphones to load the amp as we know impedance of headphones is depends on frequency so for eg. running 300ohm headphone the impedance (min) low as 300ohm be only on low octave, the mid and up will be more then minimum(300) so the arta or rmaa measure show only part of spectrum, so measurement of THD,THD+N could be corrupted - read (overstated, better then really is).

You will need few resistors in value 32,50,300 and maybe 600 ohm, and 1nF capacitor in parallel with the resistors to simulate the capacitive load as well.

 

[hifimanrookie]

Yepyep..and. Ithink i was one of the persons who restarted  this thread with my questions bout my mighty 337

 

[telecaster]

Quote:

Holly molly, this thread is busy like never before!!! good to see the LF&DV community grows in strength.

 
 
Telecaster,
My DK339 is upgraded to fixed bias, the first version of the DK339 was based on the original LF339. My present DK339 contain battery bias modification.
 
I would suggest you to do measurement with ARTA over RMAA, ARTA is real time spectrum analyzer.
You will need a True RMS DMM to calibrate the in/out of your sound card, the multimeter have to be at least True RMS to 400Hz but strongly suggest 1000Hz and over! (any cheap DMM even if say TrueRMS they are NOT!) My 2 old multimeter are not but I got for Christmas One who can handle all the frequency and much more, so my earlier graphs(arta not calibrated) more or less reliable, but very useful tool when you compare(the same setting in arta) before and after.

To measure the FR the calibration is not necessary.
very important! - to do proper measurement  u will needed LOAD and only amp with dummy load resistor show how good or bad the amp is. I tell u why....running the test with the dummy load resistor, the impedance is not changing with increasing frequency (is constant), but some people used headphones to load the amp as we know impedance of headphones is depends on frequency so for eg. running 300ohm headphone the impedance (min) low as 300ohm be only on low octave, the mid and up will be more then minimum(300) so the arta or rmaa measure show only part of spectrum, so measurement of THD,THD+N could be corrupted - read (overstated, better then really is).

You will need few resistors in value 32,50,300 and maybe 600 ohm, and 1nF capacitor in parallel with the resistors to simulate the capacitive load as well.

Thanks a bunch Wall-E, I can't thank you enough for all you have done for me and for us modders! I'm very interested in the battery bias, and any insight on the mod would be greatly appreciated! I will try to get all the hardware ready for measurements, my soundcard is kind of middle grade, it's a FireWire TC electronic desktop, but I think it's OK for the job. I guess the eBay sub 100 bux chinese true RMS DMM are not true RMS?
 
Now I'm pretty excited I want to upgrade my blue yellow mod to battery bias! Long live this thread!

 

[RickEC]

Yo XMDKQ, Darkvoice maker, thanks for making such a great amp. As you can see in the picture, it now serves as both headphones amp and pre - amplifier for my speaker system. It is actually quite good as a preamp, why does your 339 now does not have a line out? I bought this amp in 2008 I think, and never need to upgrade.
 
https://www.dropbox.com/s/3ysqham7ysst4xj/1.jpg

 

[Chodi]

So I take it that both the current Darkvoice and the La Figaro products are all designed by the same man, XMDKQ. He obviously knows a thing or two about amplifier designs. I use the LF332C with my T1's and I like it. I would have stepped up to the LF339 long ago if it were not for the two volume controls. For an amp that is only single ended I really don't get the design purpose of two volume pots. Seems like unnecessary expense. I don't want to be fiddling with two pots every time I go to change the volume. I have to say that MR. XMDKQ is one very good headphone amp designer.

 

[kramer5150]

Quote:

Yo XMDKQ, Darkvoice maker, thanks for making such a great amp. As you can see in the picture, it now serves as both headphones amp and pre - amplifier for my speaker system. It is actually quite good as a preamp, why does your 339 now does not have a line out? I bought this amp in 2008 I think, and never need to upgrade.
 
https://www.dropbox.com/s/3ysqham7ysst4xj/1.jpg

 
x2... I sometimes use mine to feed a larocco PPA.  It warms up the amp for my "colder" cans and also helps to layer the soundstage distances more.  My particular PPA by itself can be a bit distant sounding with the HD580 and K701.  I'd love to try it as a 2CH speaker preamp some day.
 
Quote:

So I take it that both the current Darkvoice and the La Figaro products are all designed by the same man, XMDKQ. He obviously knows a thing or two about amplifier designs. I use the LF332C with my T1's and I like it. I would have stepped up to the LF339 long ago if it were not for the two volume controls. For an amp that is only single ended I really don't get the design purpose of two volume pots. Seems like unnecessary expense. I don't want to be fiddling with two pots every time I go to change the volume. I have to say that MR. XMDKQ is one very good headphone amp designer.

I find it useful to help re-center stereo images that are engineered/mastered off center.  Particularly live recordings that at times place hotter mic'd instruments off to one side.  Its not often though, just every once in a while depending on the material.  IMHO the dual vol control is much more of a useful feature today with bands mic'ing more and more instrumentation on stage, and engineers placing more ambient mics throughout the venues.  With blue ray DVD driving the consumer market for more audio tracks and multiple viewing angles, separate volumes puts the listener in control of what they want to hear.
 
Just last night I was listening to Jethro Tull and Ian Andersons flue riff towards the left was getting drown'd out by Martin Barrs guitar lead.  I was able to up the left side just a little to bring a better balance to the mix.  Of course I had to balance it back once that passage was done.  It would have been annoying to just leave it that way.
 
x2... Mister xmdkq really knows tube design, and the end result speaks for itself with these amps.

 

[RickEC]

Quote:

So I take it that both the current Darkvoice and the La Figaro products are all designed by the same man, XMDKQ. He obviously knows a thing or two about amplifier designs. I use the LF332C with my T1's and I like it. I would have stepped up to the LF339 long ago if it were not for the two volume controls. For an amp that is only single ended I really don't get the design purpose of two volume pots. Seems like unnecessary expense. I don't want to be fiddling with two pots every time I go to change the volume. I have to say that MR. XMDKQ is one very good headphone amp designer.

After some time, controlling the volume using two hands becomes 2nd nature, done in a second or less. I may have more problems without the two volume pot, than with. My signal splits into left and right after my DAC, via DV337, dual mono amp, speakers cables, then my speakers. The two signal and power lines have a series of components that may not be well-matched. I do find the two volume pots let me get the volume balance just as my ears like it. I suspect my two ears don't have the same sensitivity as well. I appreciate the dual volume potentiometers. Oh did I mention that one of my Grado is known to have L/R matching issue?
 
Quote:

 
x2... I sometimes use mine to feed a larocco PPA.  It warms up the amp for my "colder" cans and also helps to layer the soundstage distances more.  My particular PPA by itself can be a bit distant sounding with the HD580 and K701.  I'd love to try it as a 2CH speaker preamp some day.
 
I find it useful to help re-center stereo images that are engineered/mastered off center.  Particularly live recordings that at times place hotter mic'd instruments off to one side.  Its not often though, just every once in a while depending on the material.  IMHO the dual vol control is much more of a useful feature today with bands mic'ing more and more instrumentation on stage, and engineers placing more ambient mics throughout the venues.  With blue ray DVD driving the consumer market for more audio tracks and multiple viewing angles, separate volumes puts the listener in control of what they want to hear.
 
Just last night I was listening to Jethro Tull and Ian Andersons flue riff towards the left was getting drown'd out by Martin Barrs guitar lead.  I was able to up the left side just a little to bring a better balance to the mix.  Of course I had to balance it back once that passage was done.  It would have been annoying to just leave it that way.
 
x2... Mister xmdkq really knows tube design, and the end result speaks for itself with these amps.

 My amp are digital, completely cold. The tubes of DV337 gave my music some texture I suspect.

 

[telecaster]

the dual mono design in the 339 like with monoblock power amps help bring soundstage better during demanding fortissimo passage in music. Only one power supply for two channels is a compromise.
A single volume control is a compromise costwise because it cost half. Adding a balance control is another compromise to the sound. Dual mono is the best way to design a truly great amplifier in the tube world.

 

[hifimanrookie]

Quote:

the dual mono design in the 339 like with monoblock power amps help bring soundstage better during demanding fortissimo passage in music. Only one power supply per channel is a compromise.
A single volume control is a compromise costwise because it cost half. Adding a balance control is another compromise to the sound. Dual mono is the best way to design a truly great amplifier in the tube world.

+1 i totally agree..if only there existed a completely balanced 337's or 339's..that woud be THE AMP..

 

[kramer5150]

Curious with all the capacitor upgrades you guys are doing and the total capacitance increase throughout the circuit... do you guys have to upgrade the power fuses?  A capacitor is a current drawing component right?  So increasing the farad capacity will increase circuit draw from the power source... right?  I ask because I was at a meet once and I blew a fuse on my 337 when I first went to power it on.  Never had that problem before, replaced the fuse on the spot and its been fine since.
 
???

 

[telecaster]

Quote:

Curious with all the capacitor upgrades you guys are doing and the total capacitance increase throughout the circuit... do you guys have to upgrade the power fuses?  A capacitor is a current drawing component right?  So increasing the farad capacity will increase circuit draw from the power source... right?  I ask because I was at a meet once and I blew a fuse on my 337 when I first went to power it on.  Never had that problem before, replaced the fuse on the spot and its been fine since.
 
???

Never had a blown fuse on this side of the pond, have more to do with your main imho.

 

[snip3r77]

I've been looking for an amp since 2 months ago.

Didn't pull the trigger on the 339 due to the costly NOS tubes. Can some one talk me to it?

 

[wazzupi]

you can get tubes pretty cheap that are still quality and sound good at least to those that own the 339 http://www.headfonia.com/lafigaro-339-my-fav-otl-amp/ check this out the first set of tubes he uses can be found for under 50 dollars for all 4 tubes. 

 

[Ultrainferno]

Quote:

you can get tubes pretty cheap that are still quality and sound good at least to those that own the 339 http://www.headfonia.com/lafigaro-339-my-fav-otl-amp/ check this out the first set of tubes he uses can be found for under 50 dollars for all 4 tubes. 

 
Exacty, the tubes in my 339 are the cheapest of all my amps. Other tubes are easily 100€ for a GZ33 or GZ37, and hundreds for a pair of 300B. The 339 tubes are cheap.

 

[wazzupi]

what do you currently have in your 339 ?