The Mjolnir 2 thread

A mix, but my main headphones are the Beyer DT1990 Pro I'm sending off to be rewired for balanced use. With SS, these cans are a hair too bright and I want tubes to knock that down just a smidge. Tonally, they are close to perfect everywhere else. I'm basically looking for a highly detailed amp with good dynamics and with just a bit a tube warmth. The Mj2 seems to fit the bill based on what I've read. The DAC will probably be an Emotiva Stealth DC-1 until I can save up for a Gungnir Multibit.

 

Gotcha. You probably wouldn't want a Jot for those. The emotiva is good choice for dac in the meantime. It's got balanced outputs and should sound great through the M2

 

You should listen to @philipmorgan , the SE input on the Mjolnir 2 is fine. If you have a source that can produce both balanced and SE output then it may be preferable to use the balanced one into Mjolnir 2, but if you only have a SE source like Modi Multibit then don't see this as a reason not to get a Mjo 2. I plugged my turntable into the Mjo2 SE inputs and it sounded great.

This question was also asked on p4 of this thread (are the single ended inputs "gimped"?) and you can read the following response there

On the other hand, as others have said, you should definitely use it balanced out to your headphones, it sounds like crap otherwise.

 

Tried a Jot with them, much too bright, too bad because I loved the detail. I haven't tried the Emotiva yet but I spoke to a few people on Headfi who had experience with it and Schiit Multibit's who thought it would be a good placeholder until the Gungnir Multibit arrives. It has balanced out which is a huge plus.

 

Personally the Mojo2 with stock tubes (and 396As to a lesser extent) and rewired DT 1990 were a smidgen "off" (please note that I tend toward warmer and darker; the 650M remains a fave); there was something etched in the treble, and vocals sounded a bit too forward. On the other hand, if you enjoy the stock DT 1990 with either set of pads, you may appreciate the slightly more taut bass from balanced out. The soundstage wasn't considerably deeper or taller, but you can adjust with tubes.

 

650M = Senn HD650?

Have you tried the Beyer Amiron? It is the warmer, smoother tuning of the DT1990, the treble is supposedly much less harsh and the overall tuning is more balanced and U shaped, very HD 650ish. I have some on order but I worry that the warmer signature combined with the tube warmth of the Mojo2 might be too syrupy.

 

So, I rolled some Phillips Miniwatt tubes into the M2...f**k, they are microphonic as hell! Even with tube dampers, they ring like all hell. I think I may get rid of them and stick with the Siemens/RCA gold pins. Sucks, 'cause they sound great, tonally, but any touch on my keyboard or desk makes them ring. Incredibly sensitive.

 

You're probably not going to hear much of a difference with DACs using relatively distorted Beyers. Try Sennheisers, Focals, or better yet speakers.

 

I can most definitely hear the differences in DACs with my DT1990 Pro. Other than the treble being ever so slightly hot (nowhere near as hot as the older 990), I'm not sure what distortion you could be referring to. IMO the Focal Elear has some pretty significant tuning issues as well.

 

The modern Beyer house sound is pretty far removed from the HD6X0 signature. I've only heard the T1.2, but people I've talked to who have heard both as well as graphs suggest a similar abortion of a tuning.

 

It almost seems as if Beyer doesn't really have a "house" sound anymore. The 1990 sounds nothing like the T1.2. I've heard both. Totally different tuning. Beyer is sort of all over the place, which I guess is a problem for some.

 

I found 8 PCC88's for $20, and when the box arrived there was one Valvo PCC88 pinched waist in there. Running it in Vali2 right now. It's a blusey tube! Reminds me of that song with Willie Dixon & Memphis Slim; "I'm built for comfort. I ain't built for speed. I've got everything that a good girl need".
The sound of the tube in Vali2 doesn't translate to MJ2 of course, but it's a good tube. Recommended.

 

I just found an untested pair of the 2C51L SER, I'll get back with impressions.

In the meantime if you want to read up on the Swedish LM Ericsson 2C51 tubes relevant for Mjolnir 2, check this out:
The first link is to the Ericsson Review Vol 31:3 from 1954, but I've cut out the relevant quote for you to read.
First about a general need to develop a very reliable and long life tube. (Page 28)
http://ericssonhistory.com/Global/Ericsson review/Ericsson Review. 1954. V.31/Ericsson_Review_Vol_31_1954_3.pdf

...then they went on to use that same manufacturer (SER) to develop the 2C51L (L for long life) which we can use in our Mjolnir2 with adaptors. From the Ericsson Review Vol32:1 1955, Page 31 onwards

http://ericssonhistory.com/Global/Ericsson review/Ericsson Review. 1955. V.32/Ericsson_Review_Vol_32_1955_1.pdf

 

This is my third pair of the Swedish made 2C51.
I've got one version branded with 2C51/396a (O-getter steel pin), one branded with RYC 2C51 (D-getter, steel pin) and now this one which says SER 2C51L.
It's an O-getter tube with steel pins.
SER was a Swedish supplier of tubes for LM Ericsson who wanted to have a long life version of 2C51 called 2C51L.
I don't know what the RYC abbreviation means but it could potentially be another external supplier of tubes.

Haven't heard the gold pin versions of this tube, but the SER version sounds absolutely fantastic.
I've said before that the LM Ericsson 2C51 is equal to the Western Electric 396a and this one is no exception. I'll try to do a better head-to-head comparison, but until then I can recommend getting it as an alternative to the Western Electric which is getting really hard to find.

 

You must have socket savers AND the adapters in that photo?

 

Indeed. Like small beacons

 

Which socket savers do you use? These would be helpful when tube rolling since it's just a PITA in get them out.

 

I bought the one from Tubemonger, but I know there's more types out there...
Then I use a wooden tongue depressor to hold the socket saver in the socket when changing tube.

 

I've been running my Mjo2/Gungnir Multibit for a couple of weeks now, listening through T5p Gen2's that I bought as portables. I got a call from a local shop that my Ether Flows ought to be available for pick up today which I anticipate will be an upgrade to my desktop setup. I'm not actually sure what tubes I'm running now as they were tossed in to the box by the seller.

I'm seeing the comments re the Western Electrics 396a tubes and before I buy the wrong thing yet again (through the process I've ended up with a breakout cable and some XLR mic cables that I don't have immediate use for )I wonder if someone could confirm that these are the right tubes?

https://www.tubedepot.com/products/396a-2c51-we

Thanks and Cheers,
-Bill

 

$100 EACH?! That's $200 worth of tubes - adapters excluded.
May I ask what the purpose of spending that kind of money on tubes is?