ALO Pan Am desktop/portable headphone amp/DAC: Impressions and Reviews
Jan 10, 2015 at 2:03 AM Post #932 of 1,147
Very interested to hear the differences with Telefunken's
 
Jan 13, 2015 at 10:54 AM Post #934 of 1,147
Yesterday I received 2 sets of Raytheon tubes:

 

1. 1967-1970 JAN-5654, Black Plate, Top O (these have Red/Orange silk-screened markings (eBay $36.95 with shipping).

 

2. 1944 Military Spec JRP 6AK5; Side Getter and Oval Plates; gray/white markings (eBay $73.50 with shipping).

 

I gave these a quick listen on the LCD-X and also listened to my Telefunkens for a comparison/reference. Both sets of Raytheons were right out of the box NOS - no burn-in.

 

I did not care much for the 1967-1970's. They sounded mid-centric and were light on bass, but the biggest problem I had with them was the congested rendition and limited sound stage (very left-right and shallow). In full orchestral passages, there was no air and instruments muddled together and became indistinct. They sounded better with string quartets and vocals, but nothing special. Perhaps with adequate burn-in, their midtone emphasis might be nice for vocals or small jazz ensembles, but considering all of the other good tube choices out there, I'm not optimistic that these will ever make the A team.

 

Different story for the 1944's.  These sounded very nice indeed, even right out of the box. I would say that they were almost comparable to the Telefunkens, and with some burn-in, I believe they may equal them. The soundstage was medium-deep with plenty of air. All frequencies were well rendered. My only nit-pick is that there was a slight edginess to the sound - not sibilant, but a tiny bit harsh. The Telefunkens, by comparison, were smooth as silk at all frequencies.  I believe though that the Raytheons will smooth out as they burn-in and turn these into a superb set of tubes.

 
Jan 13, 2015 at 4:35 PM Post #935 of 1,147
So Telefunkens remain n°1 :wink:
 
Jan 14, 2015 at 10:49 AM Post #936 of 1,147
So Telefunkens remain n°1
wink.gif

 
Well, for me at least, yes 
normal_smile .gif

 
Jan 16, 2015 at 5:24 PM Post #937 of 1,147
Got some Mullards recently. Good stuff. Need to listen more but initital impressions more solid state and less tubey magic midrange sounding than my RTC tubes, Mullard soundstage is niiiiice. Pairing with HE-500 probably better than with the RTC tubes. But LCD-2 and XC are my main headphones for Pan Am and currently Mullards vs RTC is a matter of sound preference. Life is good =)
 
Jan 17, 2015 at 12:07 PM Post #938 of 1,147
I've a question: inside the pan am are 2 capacitors with 10 mF an 50 Volts and I guess they are in the signal pass. Has anyone changed them to bigger once, e.g. 22 or 47 mF to get a better signal power in the bass range with iem's with a low impedance like the AKG K3003?
 
Jan 20, 2015 at 7:50 PM Post #939 of 1,147
Telefunken vs. Raytheon:
 
  1. ​Raytheon has a slightly leaner midrange. Sounds cleaner so with complex or thinly-textured music, this is good, but with thickly-textured stuff, the Tele is more fun
  2. The Tele has better treble texture/air. Hi hats on the Raytheon are a little less articulate. 
  3. Bass is very very close. The edge might go to the Raytheon in quantity (by a hair). Neither is bloated or understated. Very nice on both kick drums and uprights.
 
Just for clarification, the Raytheons are NOS JRP 6AK5 and the Teles are NOS 6AK5Ws
 
Jan 26, 2015 at 5:27 AM Post #940 of 1,147
Mullards amazing pairing with the LCD-X! The LCD-X turned into a very musical but still very detailed headphone! Wonderful pairing I wish I had the LCD-X too!
 
Jan 29, 2015 at 2:30 PM Post #941 of 1,147
  Mullards amazing pairing with the LCD-X! The LCD-X turned into a very musical but still very detailed headphone! Wonderful pairing I wish I had the LCD-X too!

 
I have tried a bunch of tubes and nothing has beaten the Mullards - love em. RTC comes in second for a detailed, but slightly bright, sound.
 
After a lot searching I have finally found a pair of NOS Telefunkens. $95 for the pair on Ebarf - crazy money for tiny tubes - but they are so hard to find now.
 
Jan 29, 2015 at 4:16 PM Post #942 of 1,147
I have tried a bunch of tubes and nothing has beaten the Mullards - love em. RTC comes in second for a detailed, but slightly bright, sound.

After a lot searching I have finally found a pair of NOS Telefunkens. $95 for the pair on Ebarf - crazy money for tiny tubes - but they are so hard to find now.


Hmm RTC bright... What headphones are you listening with?
 
Jan 29, 2015 at 6:17 PM Post #943 of 1,147
Hmm RTC bright... What headphones are you listening with?

 
SE535 IEMs.
 
When I say "bright", I mean "bright compared with the Mullards" - which are slightly dark.
 
The RTC have a little bit of treble emphasis to my ears, but I am used to gear that rolls off the treble a little.
 
Jan 29, 2015 at 8:25 PM Post #944 of 1,147
SE535 IEMs.

When I say "bright", I mean "bright compared with the Mullards" - which are slightly dark.

The RTC have a little bit of treble emphasis to my ears, but I am used to gear that rolls off the treble a little.


Agreed. RTC would be the solid state sound whereas Mullards and Teles are more tubey.
 
Jan 30, 2015 at 8:06 AM Post #945 of 1,147
Agreed. RTC would be the solid state sound whereas Mullards and Teles are more tubey.

+1. The RTC sounds like more of a solid state but retaining some magic of tube on the midrange :)
 

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