Rode K2 mods? tube change?

Hey everyone,

Just did a recording over the weekend of a female singer songwriter. Just acoustic guitar and vocals, and i noticed that my K2 mic sounded a little spitty in the high end. Not so much siblant, but more grainy. :?

Did a quick search on this and a few other forums for any info.
I know that a lot of people have changed the tube for some sort of NOS tube, and some say they've had good results, while others say they didn't really hear much difference at all. (I think Gus said not much of a change)

Now normally i'd just order some tubes and chuck em in, but since my car decided to crap out in every possible way, cash for a couple of tubes may be a little scarce at mo, so I'd like to ask if you guys have had any experience before I get something that could be a waste of time.

cheers

Steve

Although I do not own a Rode tube mic I have expierenced changing tubes on my Apex 460 mics with great results. I have found that you do get better audio with better tubes Where I differ though is, I prefer to not use AX7 tubes as I feel they are too noisy and too much high gain. So when I swapped the tubes in my 460's I used AT7's VS ax7's I found the at7's to be much more musical and less noisy as they are not such a high gain tube. I didn't even go with NOS tubes Just a decent AT7's. :thumb:

cheers Puncho,

i'm not too sure how the 6922 relates to the ax7 type and stuff. but i know that it is a chinese tube. so it could probably be bettered.

My K2 had a china tube stock. I tried a few russian 6dj8 types and a nos 6922 USA. I did not note much of a change the 6922 might have been a little better.

I would try a nos 6dj8/6922 I would not worry to much about brand more that it was NOS.

I have three Rodes a NTV, a modded nt1000 and a modded K2. I like the K2 capsule the most out of the three Rodes I own. The K2 capsule seems to have less of a high end rise compared to the other Rodes.

It's completely differnt but the a good 6922 will improve things especially over a cheapo tube. Looking at duncan amps Tube data sheet stuff
I found this.. so might be able to pop in something else and see how well it works or if not just replace the same tiube with a better one. the only problem I can see is if they soldered the tube in that would blow big harry moose cock...


Close or identical 6922WA, CCA, CV10320, CV2492, CV2493, CV8065, E88CC, E88CC01, ECC868
Different rating or performance 6DJ8, 6N23P*, CV5358, ECC88
Different filament voltage PCC88, UCC88

The K2 capsule seems to have less of a high end rise compared to the other Rodes

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Yeah, I definitley agree on that too. I also have on old NT2 which sounds quite scooped in the mids and very bright. I thought it sounded pretty cool when i first got it. ha ha
However, now that my pre's and convertors have gotten a lot better, bright mics just seem outta place and too much for my ears now.

But I'm def ken for me K2 to sound a bit smoother. :thumb:

Once again I'm porbably showin my ignorance here, but Gus did you think those caps in the K2 are worth taking out & replacin it with somethin a bit fancier :wink: (i read in another thread that you thought that a tube change is really the only mod suitable for a K2/NTK) They just cheap hitiano caps aren't they? or are they not in the audio path?

I've got an NTK here and I've had problems with the exact same "sizzle" in the high end. I got mine dirt cheap because it had a blown tube and the previous owner thought it was the diaphram :wink:. The first tube I put in was an Electro-Harmonix 6922 which is the tube I had when I noticed the sizzle. I just swapped it out with a JAN Phillips 6922 to see if that will improve things, I've heard its a "smooth" sounding tube but who knows if that will apply to tube mics... I'll let you know what the outcome is but I have a feeling it'll be a very minimal difference.

I'd also love to know about other mods such as changing caps etc. that I could do to get the most out of this mic. Is there anything in the audio path in the power supply that could be improved?

Cheers

A K2 is not at all like the apex.

Do a search for the NTK work I did with bluebird. IMO a 6dj8 type is not a good tube for tube microphones.
There is one design that uses it in a good way.
I tried different 6dj8 tubes in mine before I modded it not much difference maybe the JAN 6922 was the best. If you look at the schematic you might figure it out. Its a -1X gain stage with high current drive.
The stock tube is not cause of the grit IMO if anything it smooths out the sound being a 6dj8 type.

I like my modded K2 in omni I think it might make a nice single drum overhead in omni.

This is a good example of something I will not share on the web(the K2). I am still waiting for all the copies of the NTK mods from the work of Bluebird and myself in the past being passed off as others work.

Hey Gus,

I found the stuff on the NTK mod at the diyfactory page, a couple of days after I posted that last post......... Shows what a little bit of xtra searching can do.

I found i can get some rubycons even in the 160v, which I think I'll go for, and their low Z ones for the smaller values. I'm a little bit cautious about the SMD stuff as I've never worked on that stuff before, but it's always good to learn. I just dont want to stuff my main vocal mic :?

I think I'll leave the tube for now. I may be able to try a friends amperex 6922, for a quick comparison, but I'm not expecting too much from that.

This is a good example of something I will not share on the web(the K2). I am still waiting for all the copies of the NTK mods from the work of Bluebird and myself in the past being passed off as others work.

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Fair Enough. I'm just grateful for the info you guys have shared with us. The info on the NTK is more than enough to get me on my way, and maybe experiment & learn a bit for myself. :thumb:

Long term I plan on getting another K2 to use for a G7 type mic, to see and hear if the differences in the circuit are subtle or quite dramatic. Thats a bit later on tho.

Hopefully, one day I'll have some info to share with the group, rather than bein a noob, and leeching of the learned brains around here. But I think I've got a lot of catching up to do :wink:

regards,

Steve

Its cool that you are going to change some parts. FWIW I like rubycon electros for >100V ratings. IMO You don't need to change the ceramic comp cap and the .0056uf RFs at the output I did some tests I don't hear them. The .1uf and two electros, play here.

When you remove the PCBs be very carefull unsoldering the wires to the capsule make sure the PCB in that area is very clean when you solder them back in.

The circuit has a lot of feedback but is a very cool circuit it has enought current drive to work well.

The power supply is fine stock very well built IMO.

I like the new rode builds I find my modded nt1000 to be bright a rode to look for is the NTV. I have one change the stock china tube to a good NOS The grill electronics(blackgate cap, jenson transformer etc) and capsule have a nice blend IMO.

Best mod for a K2 or NTK is not to buy one IMO! Theyre alright, until you hear something half decent.


M

****, I thought all those Rode mics were good as long as you put them into a 99V:

http://www.groupdiy.com/index.php?topic=9477

:wink:

Hey the 99V pre is amazing but if yer mic is too bright, it aint gonna help you much. Its still interesting what a really good pre can do for an average mic though.

BTW my exceptions to the Rode rule are the Classic I/II and the NTV. Theyre all pretty ok mics. Also the lowest selling of the Rode line :?


M

****, I thought all those Rode mics were good as long as you put them into a 99V:

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Ha!! well the nt2 in omni actually works on acoustic guitar quite well, but I haven't found much else it's good for. Door stop? Paper weight? :grin:

Best mod for a K2 or NTK is not to buy one IMO! Theyre alright, until you hear something half decent.

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Yeah I'd love sumthin half decent, but until the ol savings start piling up (which is very rare) i think i'll go with the $15 it'll prob cost me to replace some of those caps. The tube can wait.

Besides I got the mic at a ridiculous cheap price through work. So if all else fails, It'll make a good body for a G7. cable and box supplied.

From those posts, you'd think rode was made in NZ or something :wink:

For something decent thats cheap, some of the cheap ribbon mics that are coming out of China are actually quite good, and recording to digital a ribbon mic will often give you a better and easier to mix result than a cheap condensor. Also the really simple Chinese valve mics are quite respectable, tho the quality control isnt there yet. These ones are the really prime candidates for simple cap/tube changes.