[LazyListener]

The phones I use most with the 08e are the 650s (massdrop 6xx which are rebranded 650) and I didn't find any unusual brightness. 650s have more polite trebles than other phones, so if the 650s sound bright with your amp, I wonder how the brighter cans like AKGs and ATHs would behave. This leads me to speculate, if there is anything wrong with the amp. BTW, I tested another phone with this amp, the Audeze Sine which has more pronounced treble than the 650s and even that didn't sound bright at all.

BTW, I understand E10K has a built in DAC. Which DAC are you using with the 08e? Since the E10K did not sound bright to you, can you connect the pre-out of E10 to the 08e. That way, you know it's 08e that's causing the issue. Also make other people listen to the amp and get their verdict.

I used the E10K DAC line out with the 08e and Magni 2 in my testing.  I think I'm just sensitive to certain mid-treble frequencies when they're overemphasized relative to the rest of the spectrum.  This is also why 598 are my favorite cans - everything is softer, more laid back with them, and never, ever harsh, but still quite detailed.  I'm gonna try them next with the 08e and check for the brightness.

 

[erich6]

  Valve compatibility is not a secret. Even on eBay, you will find correct cross-references trying to search for 6j9p (6g9p), both are the transliteration of a Cyrillic letter "Ж". I know about one another 100% electrically compatible lamp, but dunno how it sounds, still planning to try it on. Also, there are some more from the same "family" 6ж, partially compatible.

​Thanks for all the inputs/analysis you've made to this thread.
 
Can you say specifically why the 12AX7 is incompatible despite having the same 9-pin interface? Is it because the way the twin-triode of the 12AX7 interfaces with the amp vs. the pentone architecture of the 6j9?

 

[MisterMudd]

jajajaja

So there is a reason they call this amp NOBsound - I guess I am the NOB?!?!?!


I was told these tubes:

[COLOR=111111]E180F, EF861, 6688, 12AX7[/COLOR]

E180F works. I am using Millard.

Edit: Mullard

 

[erich6]

Well, I checked the data sheets for the 12AX7 and the 6688's and I think I answered my own question.  Different pin assignments and circuits altogether so don't expect them to be interchangeable.

 

[edulov]

E180F is a full analogue valve. 12AX7 is completely different. Compare pin layout yourself
1. http://3.bp.blogspot.com/_VuFNYQK52XE/TUwT1JxygII/AAAAAAAAAWY/E6VCYUkLEDc/s1600/05309.png
2. http://www.r-type.org/pdfs/e180f.pdf

 

[edulov]

598 are better for mids and much better for treble than 650, but not so good for lows (not that bad at the same time). And they sound softer if you have sensitive ears.

 

[erich6]

So searching the internet for replacement tubes for this amp I see several sellers group the 6688/E180F as almost a generic NOS from "various manufacturers" which seem to include Sylvania, RCA, Marconi, and Siemens.  Are they all equivalent and just a "rebranding"?
 
The ones that seem to be normally called out separately are:
 
Amperex
GE (JAN)
Philips
Mullard
Telefunken
 
I guess the STC 5A/170K​ is also equivalent?
 
That's not counting the Russian and Chinese types.

 

[henkeman]

What op amps might work good with NS-08E besides LT1364CN8, NE5532, OPA2107 and AD823ANZ ?

 

[henkeman]

The tubes are not all the same. They have different characteristics. The chinese ones and the E180F that I have are very different. MyE180F are clearer with better soundstage, bass, treble etc.

 

[edulov]

  What op amps might work good with NS-08E besides LT1364CN8, NE5532, OPA2107 and AD823ANZ ?

When I decided to play with op amps I started my search with compatibility lists for NE5532/DIP8 package, looking for the description of sound signatures and checking whitepapers for electric/specs compatibility.
Complete list is much wider, but I excluded a lot of options due to strong colorization of sound signature (dark and veiled especially), lacking clarity for treble and lacking extension/control for lows.
 
But may be you want the opposite, like dark sound and cut-off for treble?

 

[henkeman]

  When I decided to play with op amps I started my search with compatibility lists for NE5532/DIP8 package, looking for the description of sound signatures and checking whitepapers for electric/specs compatibility.
Complete list is much wider, but I excluded a lot of options due to strong colorization of sound signature (dark and veiled especially), lacking clarity for treble and lacking extension/control for lows.
 
But may be you want the opposite, like dark sound and cut-off for treble?

I want it to sound natural and musical with neutral clarity(not to analytical) good soundstage bass ext. But im also sensitive to treble. Have a pair of X2:s which are great besides some treble problems in certain tracks. 

 

[edulov]

To henkeman:
 
I wanted the same, so LT1364CN8 (CN8 denotes packaging) became my choice. All I can say that both LT and NE are honest in treble, so a bright track will sound bright; but no special emphasis to be heard. Just do not use tubes  providing "lean" sound, since they tend to be way too honest with high treble.

 

[dr3wd4wg]

I tried the LT1364 and found them too bright. The LM4562's I use now with Mullard E180F maintains the characteristics of the 5532 with (IMHO) less treble roll off and lower THD and noise. I might replace the 6V power supply, as even placing my phone near the amp causes all sorts of noise.

 

[edulov]

  I tried the LT1364 and found them too bright. The LM4562's I use now with Mullard E180F maintains the characteristics of the 5532 with (IMHO) less treble roll off and lower THD and noise. I might replace the 6V power supply, as even placing my phone near the amp causes all sorts of noise.

Agree

 

[henkeman]

Ok i really like the current sound profile of 5532:s and my valvo e180f so i might buy the LM4562 to since they where cheap from trusted source.I have lt1364 on the way from china (hope they are not fake). Will LT1028 work do you think? Im also contemplating upgrading the power supply but im not sure to what since I dont want to spend to much money on it compared to the amp.