6922 Tube Comparison - NOS vs. Stock - Avalon 737sp Mic Pre

I'm testing a matched set of Telsa 6922 tubes in my Avalon VT 737sp Preamp. Several instruments were tested, including noise floor. Links below.

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[jesseesquivel]

Oh crap I heard difference day / night ! Thx now I might b interested in the Tesla tubes

[ayarloff]

What a great test! Bravo! The differences are clearly heard even with youtube MP3 quality

[charliekey]

Stock tubes sound boomy and darker, at least in this video. TESLA tubes are indeed more open and balanced with more air.

[christurbiville]

I swapped out one of my 737's for the 1973 Tesla NOS after I watched this video last year. After burning them in for a day, I found the Tesla NOS tubes to add a but more open, almost 3D, sound to my voice. I think I'm going to swap out the other 737 for Tesla NOS tubes.

[PuffTMagicDragon]

The sovtek gives you that 737 sound. I wouldn’t try selling the pre without the originals.

[AndAThirdRPM]

Telsa is my choice. Extremely quiet and the clarity and articulation will contribute and prove to be an advantage during the mixing process. Any tube that is vintage NOS always out performs todays stock tubes. I have a pair of Avalon VT-737sp and changed the tubes using the Telefunken 7308 (6922 replacement) NOS tubes. Each tube was $400.00 and have a 10, 000 hour minimum heater life each. If you are impressed with the Telsa tubes, and you should be, ... the Telefunken tubes will knock your socks off.

[tonys]

Put Gold LIon's in there and be done with it.

[GlennMarshallRocks]

Too bad you didn't do the test after you let the Tesla's break in for 48 hours or so. Preamp tubes always gain more clarity, greater transparency, the lows drop down, and details in the mids are much more noticeable after they've had a minimum 48 hour break in (which may have been significant when comparing the Kalimba in particular, given all of the harmonics and sub-harmonics that make up it's tone).


...and yes, the hissing you were hearing is a sign it's time to change the tubes, as they're worn. Avalon rates the tubes in the 737 at 5, 000 hours, and recommends changing the tubes every 2 years in units that are "used regularly" (pg 39 of the manual).

[russliquid]

Running sound clips through the mic pre would give you a more accurate ab. Generally when do comparative experiments, its favorable to have as many variables as possible the same for each group…. Including gain matching… the human ear will always choose the louder source over the quiet one… etc.

[KwasiCorream]

The Tesla are super quite. The sound is not as detailed and warm as the factory tubes to my ears, nothing that eq can't fix I assume. Great video.

[teashea]

Props on wearing gloves when handling tubes.

[bizmakerbhang]

Sovtec is a little grainy at the end, a little stiff on lows. Tesla is some more sound expanding with wider sapce, but less vibrating at the end with less grainy. I prefer Tesla. Tesla tubes will good with tight sound power amplifiers. Otherwise it will feel bubbles all over.

[BUCKSHOTSTV]

For me the stock tubes sounds better...new stock tubes most likely would’ve reduced the noise. I just ordered new ones for my 737 as noise was starting to creep in.

[claudiobaldonijr]

Sovtek by far... smoth and soft, exactly the reason why you are using a strip channel, otherwise go direct, no equalization at all

[MadaAtoms]

Why is there so much hiss on the two options in the testing section

[starboy]

Yep give me the Telsa any day of the week.

[juca]

Gold Lion ECC88 did not worked in my preamp. They almost fried it. I then went for some Dutch Phillips.

[miropopradi]

The Tesla tubes seems to be - like as better sounding for first moment but isnt.. I prefer the original tubes much better. Much solid compact sound..
Thank You for this !

[ZEALm.e.studios]

Slovtec sounded warmer
I learned when buying replacement tubes each side has a slightly different sound know what you're getting from now on my thinking is if you're not broke don't fix them I wonder how much those change after they've been used a little bit

[earlmclean]

The sovtek tubes are new? if not then perhaps you need to do another test to A/B, added noise could be due to age of tubes