[hp4fun]

I thought I would never use 7236 + mullard EF86 because there are so many "better" combinations out there. 7236 is closer to the SS sound, and EF86 works pretty well with tuby sound tubes.

I also thought I would never like my Beyerdynamic T1 because there are so many "better" headphones out there. It is so bright that causes my ear pain, and so boomy that has no separation.

But I was wrong. The (white label) 7236+EF86+T1 is a great combination that I put my 8xx and HEkse back to the box.

Then I tried red label 7236 and plastic bottom 7236 with mullard EF86, or 7236 with 6SJ7GT or 5693. None of them works quite well as above combination. I heard the separation that I never heard in T1. The boomy bass is gone. Really enjoyable.

That's why I love rolling tubes: I gave my T1 away before I had 339i, so I never heard T1 driven by 339i. I reunited with it briefly and almost gave up as T1 sounds pretty bad on some "classical" combinations for 339i. My last two test plans were the CV4079 + EF86 (tuby sound signature) and 7236 + 5693 (SS sound signature). But the last moment before I packed the tubes I decided to put the 7236 and EF86 together. And it has been there for a few days.

 

[adeadcrab]

Enjoying the HD800S with classical - Verdi's 'Aida' - from LF339 with the Cetron 7236 and 6SJ7GT mesh tubes. Fed signal from Soekris 1421 -> Topping A90D as preamp.
I find if I keep the 339 volume at 10 o'clock and increase volume from preamp I avoid the tube clipping / hollowness that I was experiencing previously. I used to attenuate the signal much more and increase the 339 volume to 1-2 o'clock.

 

[mordy]

I thought I would never use 7236 + mullard EF86 because there are so many "better" combinations out there. 7236 is closer to the SS sound, and EF86 works pretty well with tuby sound tubes.

I also thought I would never like my Beyerdynamic T1 because there are so many "better" headphones out there. It is so bright that causes my ear pain, and so boomy that has no separation.

But I was wrong. The (white label) 7236+EF86+T1 is a great combination that I put my 8xx and HEkse back to the box.

Then I tried red label 7236 and plastic bottom 7236 with mullard EF86, or 7236 with 6SJ7GT or 5693. None of them works quite well as above combination. I heard the separation that I never heard in T1. The boomy bass is gone. Really enjoyable.

That's why I love rolling tubes: I gave my T1 away before I had 339i, so I never heard T1 driven by 339i. I reunited with it briefly and almost gave up as T1 sounds pretty bad on some "classical" combinations for 339i. My last two test plans were the CV4079 + EF86 (tuby sound signature) and 7236 + 5693 (SS sound signature). But the last moment before I packed the tubes I decided to put the 7236 and EF86 together. And it has been there for a few days.

Yes- it is all in the synergy between tubes (and headphones as well). More than once it has happened to me that tubes that were relegated to storage and never used suddenly sound great in a new combination.
Now, the same tube(s) can sound different in a different amp. I assume that differences in the circuit design etc. account for that. That is why I cannot get myself to sell off tubes that I don't use - you never know when a specific tube will shine in a new combination.
All part of the wonderful tube mystique...

 

[mordy]

Enjoying the HD800S with classical - Verdi's 'Aida' - from LF339 with the Cetron 7236 and 6SJ7GT mesh tubes. Fed signal from Soekris 1421 -> Topping A90D as preamp.
I find if I keep the 339 volume at 10 o'clock and increase volume from preamp I avoid the tube clipping / hollowness that I was experiencing previously. I used to attenuate the signal much more and increase the 339 volume to 1-2 o'clock.

In my experience many tubes have some hum at high volume levels (could be the amp I am using), and by adjusting the volume levels of the preamp and the headphone amp I am usually able to reduce the noise to inaudible levels and avoid clipping as well.

 

[hp4fun]

Enjoying the HD800S with classical - Verdi's 'Aida' - from LF339 with the Cetron 7236 and 6SJ7GT mesh tubes. Fed signal from Soekris 1421 -> Topping A90D as preamp.
I find if I keep the 339 volume at 10 o'clock and increase volume from preamp I avoid the tube clipping / hollowness that I was experiencing previously. I used to attenuate the signal much more and increase the 339 volume to 1-2 o'clock.

You are probably right. HD800s works well with 7236+6SJ7GT than 7236 + EF86.

One thing I don't like 6SJ7GT: probably due to it structure, it is very sensitive to external vibration. For example, I can hear how my typing hammers my ear.

One thing I don't like EF86: it was not designed for 339i, so the internal temperature gets higher (~10F) than the 6SJ7GT which sometimes caused some smell (not burning smell though).

I guess there is no perfect answer!

 

[adeadcrab]

You are probably right. HD800s works well with 7236+6SJ7GT than 7236 + EF86.

One thing I don't like 6SJ7GT: probably due to it structure, it is very sensitive to external vibration. For example, I can hear how my typing hammers my ear.

One thing I don't like EF86: it was not designed for 339i, so the internal temperature gets higher (~10F) than the 6SJ7GT which sometimes caused some smell (not burning smell though).

I guess there is no perfect answer!

I have found that since moving my PC from the table to the ground, has reduced some of the background hum from the LF339
I also have all my hi-fi gear on a dedicated marble table and keep the keyboard away from it

 

[xtr4]

From my own experience, the SPL Phonitor XE used as a preamp into the 339 makes it dead silent and volume control is also much easier.

 

[Shinsengumi]

I like my La Figaro sound wise but don’t quite like the look of itTherefore I wonder if it is possible to change the front panel with a wood panel.

Have someone disassembled a La Figaro and could tell me if it is possible to unscrew the front panel, take off the volume pots and glue on a wooden panel (with a drilled hole for headphone input) and glue on wooden panels on the sides? Or is it a bigger operation to take off the volume pots?

I would like to have a clean front panel and instead change volume on my DAC. Is there any problems with wood and the fact that the amplifier gets hot? Thankful for any advice in this matter?

 

[colinharding]

Heat wise I’m not sure you’d want to glue panels on the side as the current panels are perforated to allow heat to escape. You’d need to at least replicate some of that with the wood paneling to ensure the amp retains some cooling ability. The wood won’t burn by any stretch if that’s what you’re asking.

The front panel I believe unscrews easily enough but taking volume pots out is going to be a headache and I’m not sure you’d want to do that anyway. Even with the DAC volume at a minimal level the 339 will always be presenting full gain and you’ll get some noise. You can try this now by turning the pots all the way up and just control the volume with your DAC. You’d probably have to add some resistors in there to set the volume at half or 3/4 permanently. You’ll also lose the ability to indeptedntly adjust both channels, which is a feature of this amplifier.

I’d go the route of changing the front panel but leaving the volume pots and just set them at a position that you’re comfortable with. Then adjust volume via the DAC.

 

[colinharding]

For a thread update on my journey with the 339 - I believe I’m now done.

I employed all the mods, the final touch was the DC heater and active filter. While I tried to install following the schematic on the thread (used a mosfet instead of igbt) I encountered oscillation with the power tube. Kept the mosfet but adjusted with a zener diode implementation instead with great results.

The amp is dead quiet until you reach the very end of the volume pot! Not bad at all! Somehow I feel like I gained some dynamics but it’s hard to tell without a direct comparison to stock. All in all…it sounds great

 

[Shinsengumi]

Heat wise I’m not sure you’d want to glue panels on the side as the current panels are perforated to allow heat to escape. You’d need to at least replicate some of that with the wood paneling to ensure the amp retains some cooling ability. The wood won’t burn by any stretch if that’s what you’re asking.

The front panel I believe unscrews easily enough but taking volume pots out is going to be a headache and I’m not sure you’d want to do that anyway. Even with the DAC volume at a minimal level the 339 will always be presenting full gain and you’ll get some noise. You can try this now by turning the pots all the way up and just control the volume with your DAC. You’d probably have to add some resistors in there to set the volume at half or 3/4 permanently. You’ll also lose the ability to indeptedntly adjust both channels, which is a feature of this amplifier.

I’d go the route of changing the front panel but leaving the volume pots and just set them at a position that you’re comfortable with. Then adjust volume via the DAC.

Thanks a lot for taking your time to answer my questions! I will ponder about this venture and see if I will do anything about the looks.

 

[adeadcrab]

The original LF339 I own is seriously impressing me lately.
If the rest of your system is capable of high resolution the 339 does not disappoint... and this is with the 5693 'red hot' driver tubes - which previously I considered to be wooly, smoothing over detail, muddy, etc... right now they are blowing my mind!
The trick is not to preamp the sound to the amp, and to keep the volume on the amp at 10 o'clock or less - to avoid that overemphasis of tube warmth. Really resolving sound - only took me 8 years to realise I had the resolution here all this time!

It's a shame that it seems the LF 339 is no longer being sold.. have to go get the LF339i which is still with the tech for modification...

 

[colinharding]

So you’ve both the original 339 and the 339i? Will be interesting to compare the two directly once the 339i is back from the tech.

I found the 339i doesn’t play well with preamps. As in dac -> preamp -> 339i. Sounds best connected directly to the DAC instead of using a preamp in between. Was easier as my preamp had a few outputs so I could spit the DAC to multiple amps instead of moving the wires each time, oh well.

 

[wwmhf]

So you’ve both the original 339 and the 339i? Will be interesting to compare the two directly once the 339i is back from the tech.

I found the 339i doesn’t play well with preamps. As in dac -> preamp -> 339i. Sounds best connected directly to the DAC instead of using a preamp in between. Was easier as my preamp had a few outputs so I could spit the DAC to multiple amps instead of moving the wires each time, oh well.

If I remember correctly, the manufacture said that this was not their better preamp ...

 

[colinharding]

That would make sense. The noise floor isn't really suitable for this to be a purpose built preamp. It can function as one but that's not its main purpose.

Even with the mods on mine it's not as quiet as my "real" preamp, it's certainly close though.