The Mjolnir 2 thread

Cheapest pairs from audiotubes.com. Anyone know if there is a reason @The Alchemist shouldn't try one of these?

5670 (2C51 or 396A ) JAN Military , General Electric Blackplate MATCHED PAIR

New old stock white box. Large stock just in! Excellent military spec blackplate GE identical to their 5-star series but these have passed the military spec tests. A very scarce, out of production, high-frequency dual triode. Sonically, these have power, yet can be delicate and very natural in their presentation, without glare or thin sound. This tube was found in a number of 1950-1960 era high fidelity receivers, plus pro audio compressors and preamps, and there are no substitutes for it. Get the real deal here! Excellent military blackplate carefully matched pairs. SINGLE TUBES ARE $15.00. Big savings over the W-E brand, with impressive performance!

$30.00 per pair

In Stock

396A (2C51 or 5670) JAN Military , GE 5-star, Raytheon, Sylvania MATCHED PAIR

New old stock, original box and white box. Most are GE 5-star. A very scarce, out of production, high-frequency dual triode. This tube was found in a number of 1950-1960 era high fidelity receivers, plus pro audio compressors and preamps, and there are no substitutes for it. Get the real deal here! Excellent military blackplate carefully matched pairs, most are GE. SINGLE TUBES ARE $15.00. Big savings over the W-E brand, with identical performance!

$30.00 per pair

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I bought a pair of the GE 5 Star triple mica tubes from Brent (audiotubes.com) and I am very happy with their sound. Not quite as nice as the WE396A but very nice indeed. A bargain at $30 for a pair!

 

Glad to hear you found the source of your problem. I think I have similiar thing with DC offset since the MJ2 physically buzzes and vibrates on startup and continues to buzz quietly.

When flicking a lightswitch I hear the pop through headphones too for example.
My sockets aren't grounded but will have a guy fix that soon. The wiring is REALLY bad in my apartment. Lightbulbs only last a few months etc.

If you get the Furman/Emotiva please report back

 

Looks like Audio by Van Alstine has something similar to the Emotiva CMX-2.

AVA HumDinger DC Line Blocker
http://www.avahifi.com/products/accessories/humdinger-dc-line-blocker

About $20 more expensive. I don't know if it is any better (or worse). Just thought I'd point it out, as a possible alternative.

 

I use the Emotiva CMX-2 it works well for me.

 

My understanding is that they all buzz during initialisation. After that it seems to vary. With mine the chassis mildly vibrates the degree of which changes depending on what outlet I am using, or even the day. It's been checked out by Mark at Schiit UK/Electromod and everything was considered fine. My conclusion was that it is related to the power that it's being fed, and perhaps that it's primary design was done at a different voltage.

I've been wanting to try some power conditioning and I think I may try that Furman you guys mentioned for RFI/EMI filtering. Does anyone know of a good DC filter alternative to the Emotiva for EU voltage?

 

I had a lot of issues with my Valhalla 2, I added a Emotiva CX-2 and Furman and it seemed to fix the issue. Also you can try a "Cheater" plug ( a 3 prong to 2 prong adapter, they are cheap). There could be many factors causing hum and buzz such as nearby electronics, cell phones, electrical interference from outside the home, o other electronics. Try connecting your unit away from anything electrical except of course for a receptacle to plug the unit in and see if that helps, or you can try taking your unit to a friend's house to see if the issue persists.

 

If you get a Furman, I would look at the PST-8 or one of their cheaper rack mount units, as all of Furman's stuff with their SMP/LIFT/EVS features uses basically the same circuit. The AC215 is not a great value considering you get the same internals and fewer outlets than most of their other products.

 

My understanding

If you're getting physical hum/vibration, you may have a DC offset in your power. See if you can get your hands on a mains isolation transformer to test.

If that turns out to work, the industrial style ones are about £100-150 for the lower power (75Wish) variants. If you want something with more explicit RFI filtering too, this doesn't look terrible:

https://airlinktransformers.com/product/conditioning-balanced-power-supply-cbs1500

Bear in mind that most of power filter manufs don't have the exact same models in 220V variants- so specific model numbers vary. I guess this might be a similar unit:

https://www.thomann.de/gb/furman_pl8_ce.htm?ref=search_rslt_furman_224463_2

..however, I'd still try a mains iso transformer first, personally.

 

Sure, good point. The model doesn't matter as long as it has their headline features, as the internals that provide them are the same regardless. I've noticed a lot of people on here ending up with the AC215 unit when cheaper or more functional models provide the same filtration.

Right, which is why people have brought up the CMX-2. I believe a similar product that is available in Europe was brought up in the power thread not too long ago.

 

Anybody have idea as to why my MJ2 sometimes physically clicks/pops really loud?
It doesn't cut music off and I don't hear it in headphones. It's also way louder than the relays that click at start-up.
The time it does make the click/pop noise seems completely random. This happens maybe 1-3 times a day and has been happening since I got the amp. (used)

 

Is it thermal expansion of the glass? Does it happen with LISST? Other tubes?

 

You may want to contact Schiit Technical Support to see if it an issue to be concerned about. I suggest emailing them as you will get a faster response. Just click on Contact on the upper right-hand side of the Schiit website page and click the support link on the left and fill out the form.

Their email is:

[email protected]

or use their help and support link on the left-hand side of the Contact page, it is the 3rd option down and fill out the form.

http://schiit.com/contact/help-support

 

I don't have LISST but yes happens with all the tubes. I also suspect that's the case, maybe the MJ2 itself is expanding. It's quite cold here when it's not on.

Will do.

 

Maybe pretend the switch in the back doesn't exist, and just leave it on?

...at least for a couple days

 

That's a good idea actually since I'm not worried about the tubes I'm using atm.

 

This started happening to me a few months ago, it's quite irritating. The sound is somewhere between a creak and a pop. It always happens about 40-60m after turn off, and will go on for a few hours. I expect it is fractional contraction of the metal due to thermal cool down causing movement where the chassis is screwed together.

 

Schiit answered and told me it's most likely the chassis settling as it's getting heated up and that it's not atypical, which is what I suspected too since really nothing else can make that kind of sound. I can live with it now knowing it's nothing dangerous.

 

If it makes you feel any better, I have been around large steel pipes that were in direct sunlight and every 30 minutes or so one of them would create a bang like a gunshot was fired. It's normal, and the metal can handle it.

 

If there is, I'm all ears- I don't think the power regeneration thread has seen posts in about a month. The Emotiva power stuff isn't made in a 220v form, either. It's much slimmer pickings for that sort of thing at non-audiophool prices here. I have been looking at industrial units (always a bit of a crapshoot regarding hum) and a couple of audio-centric ones:

http://www.talkelectronics.com/iso1-mains-isolation-filter/
https://airlinktransformers.com/product/conditioning-balanced-power-supply-cbs1500

The first one is listed by breezily confident dealers as "available" or "in stock" until you try to order them, and then they sheepishly admit that there's a general delay from the manufacturer and swear blind that they'll be available "mid-month". The second one looks promising, but is very heavy- I'm half-tempted to call them, and see what the lead time is, and if they can do nominated day delivery (as I don't fancy carrying that on a rush hour train).

If there is an affordable, high quality 220v option that I have missed, please point me at it though!