Rode NTK Test 2 - Tube swaps

Hi all-
I decided to pick up some 6922 EHG's (electro-harmonix) after my last test based on many people's opinions- maybe Bluegrassdan is right and a more expensive tube might be even better, but many people've said these are a better match for this particular mic.
see previous test for more details on my setup, but here's the brief:

orig:
Mic 1 (capsule 1), 95-4 fake telefunken tube
Mic 2 (capsule 2), 6h23N russian NOS tube (best in last test)

Setup:
Mic 1 <--- 5cm ---> Mic 2
Mics at head height, sing to middle.


first test:
capsule 1, 6922EHG tube
capsule 2, 6h23N russian NOS tube

This test showed an incredible difference between the two (guess which "won").


Second test:
Capsule 1, 95-4 fake telefunken tube
Capsule 2, 6922EHG tube

Can't be bothered posting the results (vocal harmonies) as they only re-iterated the differences exhibited above - however, they also showed (by comparing with first test) that capsule 1 seemed a bit better than 2. So I did test 3.


Third test:
Capsule 1, 95-4 fake telefunken tube

By comparing this second take of main vocal line with the ones from test 1, although the second take is weaker (delivery-wise, not volume-wise) it clearly shows that even leaving capsule differences aside, the 6922 is a massive improvement over the other two - IMHO - and for this particular application.
Cheers,
M@

[BluegrassDan]

Hey soul,

Check this out. It's a vintage RCA 6922 made in Holland - selling for $45 USD. HOWEVER - this is REALLY a relabeled Amperex tube, and it usually sells for over $120 USD, if you can find it.

Radio Tubes 1 RCA 6922 6DJ8 ECC88 Gold Pin Holland Tube - (eBay item 250187068604 end time Dec-12-07 16:02:37 PST)

Might make for a nice comparison...and a nice addition to your collection...eh?

[sexxy]

from my experience, & sending a 5Ohz sine tone to presonus bluetube
and analizing with izotope ozone or any other free oscilloscope meter like
PROGRESS AUDIO.co.uk Oscilloscope or Mdsp @ Smartelectronix Fre(a)koscope
KVR: Virtual Instruments, Virtual Effects, VST Plugins, Audio Units (AU), DirectX (DX), Universal Binary Compatibility - Audio Plugin News, Reviews and Community

the AX7 / AX7a have the most harmonics & gain, new .ru or nos silvania have similar harmonics
AT7
AU7 the less harmonics

didnt tested AZ7

personally i dont like tubes exept for snares and..., i like more trasformer sound of johnhardy m-1, but some times i like the grainy organic dark tube sound of hhb radius10
or the behringer tube, the adl600 gear slutz tests seems too clean for me, the mil-media tube pre 2b, sounds too much face lifted for me!, the uaudio 610 tube mic-pre has that vintage eq response but i like more the focusrite liquid pre savillero from halios console "no tube but even warmer", pultec or d.w.fearn or aphex 1100 are nice too...

TEST: Presonus ADL600 DeMaria valves replacement

The Listening Sessions

3D Audio Inc-Homepage

____________________________________________________________
Millennia Tube Test

Vacuum Tube Listening Test

To all users of Millennia Twin Topology and other vacuum tube equipment:
A comment we sometimes hear from customers is that Millennia's tube topology equipment "is too clean -- it doesn't sound tooby enough." Some owners want "thicker euphonic coloration" from their Twin Topology vacuum tube circuits.
In response to these customers, we've recently finished a comprehensive listening test on a modest collection of 12AX7, 12AU7, and 12At7 variety vacuum tubes. We picked NOS tubes which are readily available from specialty dealers and auctions. Here are the results of the test:
12AX7 Vacuum Tubes Under Test

• Sovtek 12AX7WA (baseline, our stock 12AX7 tube)
• Sovtek 12AX7LPS
• Mazda 12AX7 Chrome Plate (1963)
• Sylvania JHS12AX7 (1961)
• Tungsram ECC83LN
• Brimar 12AX7
• GE 12AX7 Large Plate (1963)
• Mullard CV4004 (UK)
• Philips 12AX7WA (11/86)
• Telefunken 12AX7 / ECC83 "Smooth Plate"

12AU7 Vacuum Tubes Under Test

• CIFTE 12AU7WAH (1959)
• RT Production 12AU7WA (France, 1965)
• Mullard 4003 KQDD/K
• Telefunken ECC82

For these tests, we used a number of program sources in our editing/listening room (Pass X amps, Dunlavy type 5 monitors) including Bob Katz's Chesky jazz recordings, Bruce Leek wind band recordings, and some of our own classical music recordings
Many of the 12AX7 tubes tested sounded similar to the new-stock Sovteks we currently use. However, two tubes stood out with a very pronounced sonic signature, adding what we were calling an "aura" around the music. The two tubes that were preferred for enhanced euphonic performance were the Mullard CV4004 (UK) and the Telefunken ECC83 smooth plate (Germany). Notes for the Mullard CV4004 say "adds a bit of extra dimension and body. Very sweet. Not 'hyped' in some negative way." Notes for the Tele say "Wow! Puts an 'aura' around the program. Does some interesting things to the HM and HF. Seems to lose a bit of LF presence, but gains some 'inside detail' of program (?). More immediate?"
On the 12AU7's, there were two NOS varieties that we found "positively euphonic" -- the Mullard 4003 KQDD/K box plate and a French military tube called RT Production from 1965. The RT was noted to "provides a 'sheen' on HF and HM, interesting effect on the HF's." The Mullard "adds a nice sense of brightness, but not too much. Slight loss of LF and LM. Rich in character." The other tubes tested did not sound significantly different than the new-stock Russian or Chinese 12AU7 tubes we now use.
Note that these results were found in NSEQ-2 and TCL-2 test beds. These same results may or may not be achieved in other audio equipment. Note also that we tested additional Mullard, Telefunken, and RT Production vacuum tubes and assured repeatable subjective results. Moreover, there are a myriad of other tubes that should have been included, but for reasons of time, cost, and/or availability, weren't. In the future, we may conduct additional tests if we can gather another modest stable of different NOS tubes. Comments and suggestions for future tests are invited. We also kept good notes on all the other tubes, so send an e-mail if you're interested in what we thought about the other tested vacuum tubes.
Since completing our tests, we've been stocking up on these "colorful" valves wherever we can find them.
Product Requirements:

• ORIGIN STT-1: Two each 12AX7 (4004) and 12AU7 (4003), one each 12AT7 (4024)
• NSEQ-2: Two each 12AX7 and 12AU7
• TWINCOM TCL-2: Four each 12AU7 and two ea 12AT7
• TWIN DIRECT TD-1: Single 12AT7 (4024)

What we might have available (call or e-mail for current stock):

• Telefunken (Germany) 12AX7 Smooth Plate, NOS & fully tested used
• Mullard (UK) CV4003 (12AU7) Box Plate, NOS, tested
• Mullard (UK) CV4024 (12AT7), NOS, tested

You can also find these exact tube types via on-line auctions, and from on-line tube dealers such as Upscale Audio. Please call if you have any questions. Thanks for your interest! It was a fun test.

[adresito75]

hi, i have a rode ntk mic serial 14437 but i don´t know what type of tube has inside. can you help me? i'm very interested in replacing with another like telefunken or mullard for a colored sound. thanks, bye

Originally Posted by sexxy

from my experience, & sending a 5Ohz sine tone to presonus bluetube

... WTF was that all about? Link-spam? :(
m@