[XMarsX]

The volume attenuation in most amps is fine, but by using a preamp that is designed more specifically for volume attenuation means that you are not losing the effortlessness that an amp can have when not diverting signal through even the best volume pots. Most amps that run through a transformer will also benefit greatly from running full volume, or even better by bypassing the volume pot all together and using external volume control.

Once you have heard an AVC in your chain you will know what I am talking about. Its adds clarity and purity that you would not expect...ie. it’snot subtle.

My wallet hates you. I ended up winning an auction on eBay for a nice Freya+ in silver. It gets here Tuesday.

I think I may need to downsize my PC’s monitor. My desk has become a bit crowded now that it has a Gumby/MJ2 sitting on it, and with a Freya inbound lol.

 

[Mike-WI]

2021 Apr 16 - Jason Stoddard - imminent demise of Mjolnir 2
https://www.head-fi.org/threads/sch...bable-start-up.701900/page-5012#post-16300706
(bold added)

Hey all,

I'm back in California for a while, so I figured I'd give you an update.

First, we are producing speaker amps like crazy--you'll be seeing the backorders shrink for Aegir, Vidar, and Ragnarok 2 over the next week or so as we get caught up, and the intent is to eventually get to 1-3 day shipping for all speaker power amps. This would be a first for us--these products have almost always been 7-10 days.

Second, we're building black Freya+es and seeing if anyone wants one to help clear those backorders (lots of silver orders, silver tops we are still waiting for.)

Third, we're increasing capacity again, adding additional runs at new Utah PCB assembly houses to help meet demand.

All of this stuff should help get us out of the deep backorders, get us shipping more consistently, and allow us to fully open some channels (distributors, Amazon). But again, this takes time, and it also requires no surprises in planning. There have been a lot of surprises lately, though things seem to be getting better as far as the supply chain goes.

Finally, I must announce the imminent demise of Mjolnir 2. As in, it will be dropped from the product line with no planned successor.

"Why? Why are you doing such a terrible thing?" you might ask. "I always liked Mjolnir 2!"

So did I. I still have one at home.

But there's several problems with Mjolnir 2, not least of which is that the performance of Jotunheim 2 is now so good--in a smaller, more convenient amp. Also, Mjolnir 2 uses complex transformers that are hard to get right, have long lead times, and can be variable. So it's going away.

"Will you ever do something like Mjolnir 2 again?" you ask.

As of now, we don't have a Mjolnir 3 on the books. I've played with ideas, including ones you expect (tube hybrid with Nexus and Continuity, which did not work because the tubes can't match precisely enough, and a differential operational point servo "fought" the other operational point servos, resulting in unreliable start-up) and some you probably didn't (back to solid state with relay volume and two card slots, or a differential version of Coherence, both of which weren't all that exciting).

And, here's the thing: Mjolnir 2 is huge. Any Mjolnir 3 would either be (a) the same size, not desktop friendly, or (b) a weird size that doesn't match everything we make. I'd love to go back in time and make all the "large midsize" gear not as wide, but I don't have a direct line to any rogue Time Lords. So that means we're stuck with a size that may make sense in a rack, but not so much on a desk. That's probably one reason why Mjolnir 2 was, ahem, less popular than it might have been.

So, say farewell to Mjolnir 2. If you already have one, don't worry--we'll still service and repair them for the foreseeable future (hell, we're still repairing 10+ year old Asgards to this day). And if you want one, you have a small window to pick one up before they go away. Though honestly, after living with Jotunheim 2, it's really hard to justify. But then again, I'm cheap...and I like my desk space.

Someone just liked this so reminded me of no planned Mjolnir 3 two years ago...

EDIT:
Only saw someone re-posted Jasons info after I posted this (from earlier in thread).

 

[ToddRaymond]

Jason has a bit of a habit of making it sound as though this or that will never ever happen, only to later change his mind, evidently.

At any rate, Mjolnir 3 sounds interesting!

 

[c0rp1]

Hey everyone,

Can I ask for a bit of help? After a recent move, something went wrong with my Mjolnir 2. The sound coming from the headphones became really low, even on high gain and volume pot set to max. Neither the tubes, nor the cables, DAC or other parts of my audio system are responsible for sure, because I've tried swapping pretty much everything. Furthermore, with that same setup, the Mjolnir was working perfectly fine several weeks ago. I also tried using another amplifier connected the same way to all my other gear and it had no issues whatsoever.

So here are some observations with the volume pot set to max (100%).

1. When using LISST tubes, the sound isn't distorted, but it's too low even at high gain and a little quieter at low gain (as if the volume pot is at 30% instead of 100%).

2. With regular tubes (and I've tried with 3 different pairs), there is no hearable sound at low gain. At high gain the sound is there, but again it's too quiet and is distorted.

The RCA or XLR connection makes little to no difference, the same goes for the XLR or 1/4" headphone output. In other words, no matter how I connect my headphones or DAC to the Mjolnir, the problem persists.

I'm in Europe, unit is out of warranty, so not sure how to proceed here. I've heard of some bad stories about the time it takes schiit-europe to actually diagnose a problem and an eventual repair afterwards (don't think they have a repair center here, so they might be shipping the devices back to the States). I have almost no technical knowledge myself, so even if I disassemble the unit, I don't know if I'll be able to see something wrong with it. I could perhaps try to find a person locally who deals with stuff like that, but would prefer to have an idea in advance if this might be caused by a capacitor, resistors or something similar.

I'd appreciate any advice possible. Thank you in advance!

 

[ShortBtwnHdset]

Boy, unfortunately, the best advise I can give is very generic, as I'm no technician, and no one other than Schiit has schematics. Being that this is a tube headamp, there are some DANGEROUS VOLTAGES YOU'D BE PLAYING WITH!

Problem seems to be in both channels, by your description, so sounds like there is a gain stage out. Are the tube heaters glowing? If not, your tubes will never operate properly. Does the volume control have any effect? If it does, then likely (but not definitley) you could skip over the 1st gain stage and the volume pot sections. Does the startup, output shorting relay click after the normal approx 30 seconds. If you don't hear the click, your headamp is never coming out of warm-up/standby mode, where it shorts the output to keep from frying headphones/tubes during warm-up. Does activating the High gain/low gain switch correspond with a relay click? If not, something is wrong with that relay switching circuit on both channels. These things can be confirmed without too much trouble or even using a meter.

If you're VERY proficient with a meter AND ARE EXCEEDINGLY FAMILIAR WITH AND EXCERCIZE PROPER CAUTION WITH HIGH VOLTAGE CIRCUITS/EQUIPMENT, I would next check all the bridge rectifiers for proper impedence (Diode and resistance checks on a mutlimeter), I believe they should measure similarly (unit unpowered, and remember those caps most likely still have a dangerous charge, SO CAUTION). Next check voltage rails for the various supplies (each can be identified by the labelling on the transformer, the 150V rail (HIGHLY DANGEROUS), 14V rail, 8.5V rail, and the 4 X 19v rails (consider all PS rails to have DANGEROUS charge levels), Of those rails, concentrate on the first 3, as it seems a gain stage is out. Check the voltage out of the bridge rectifiers to confirm that none are fried, the 150V or 8.5V rails being down would keep the tube stage from working, a possible culprit. The 14V rail likey operates relays and 1st gain stage, and the 4 X 19V rails likely are for the large power transistors. These are all guesses on my part, just how I would proceed WITH GREAT CAUTION. AGAIN, I'M NOT RECOMENDING YOU DO THIS. I do think that most repair shops could do this much fairly easily. If it's past that, Schiit's your best alternative. You might still want to call them and get recomendations, from what I hear they are at least sympathetic and may be able to give better advice.

My 2 cents, and still the best advice would be to call Schitt.

 

[c0rp1]

Boy, unfortunately, the best advise I can give is very generic, as I'm no technician, and no one other than Schiit has schematics. Being that this is a tube headamp, there are some DANGEROUS VOLTAGES YOU'D BE PLAYING WITH!

Problem seems to be in both channels, by your description, so sounds like there is a gain stage out. Are the tube heaters glowing? If not, your tubes will never operate properly. Does the volume control have any effect? If it does, then likely (but not definitley) you could skip over the 1st gain stage and the volume pot sections. Does the startup, output shorting relay click after the normal approx 30 seconds. If you don't hear the click, your headamp is never coming out of warm-up/standby mode, where it shorts the output to keep from frying headphones/tubes during warm-up. Does activating the High gain/low gain switch correspond with a relay click? If not, something is wrong with that relay switching circuit on both channels. These things can be confirmed without too much trouble or even using a meter.

If you're VERY proficient with a meter AND ARE EXCEEDINGLY FAMILIAR WITH AND EXCERCIZE PROPER CAUTION WITH HIGH VOLTAGE CIRCUITS/EQUIPMENT, I would next check all the bridge rectifiers for proper impedence (Diode and resistance checks on a mutlimeter), I believe they should measure similarly (unit unpowered, and remember those caps most likely still have a dangerous charge, SO CAUTION). Next check voltage rails for the various supplies (each can be identified by the labelling on the transformer, the 150V rail (HIGHLY DANGEROUS), 14V rail, 8.5V rail, and the 4 X 19v rails (consider all PS rails to have DANGEROUS charge levels), Of those rails, concentrate on the first 3, as it seems a gain stage is out. Check the voltage out of the bridge rectifiers to confirm that none are fried, the 150V or 8.5V rails being down would keep the tube stage from working, a possible culprit. The 14V rail likey operates relays and 1st gain stage, and the 4 X 19V rails likely are for the large power transistors. These are all guesses on my part, just how I would proceed WITH GREAT CAUTION. AGAIN, I'M NOT RECOMENDING YOU DO THIS. I do think that most repair shops could do this much fairly easily. If it's past that, Schiit's your best alternative. You might still want to call them and get recomendations, from what I hear they are at least sympathetic and may be able to give better advice.

My 2 cents, and still the best advice would be to call Schitt.

Thanks a lot for taking the time and writing such a long reply, really appreciate it.

To answer all the questions mentioned above:
1. Yes, both channels have the problem and it's pretty much identical.
2. Yes, tube heaters are glowing.
3. Yes, volume control has an effect.
4. Regarding the relay click on startup, here's what I observed:
- With LISST tubes - when I power the unit on, no matter if it's set to low or high gain, I hear a pronounce click after around 15 seconds. Same goes for if I switch between low and high gain (and vice-versa) when the unit is already on - after 15 seconds the relay clicks.
- With regular tubes - when I power the unit on low gain, there's no relay click whatsoever. If I power the Mjolnir on high gain though, the click is present. Same situation with using the switch when the unit is already on - if I'm going from low to high gain the click is there, if I'm going from high to low, there's no click.
This might explain why I'm getting no sound whatsoever coming from my headphones when I'm using regular tubes and the Mjolnir is set on low gain.

I have almost no experience with multi meters, so all the measurements you mentioned, I'll leave to a professional. I hope that the relay clicking on certain occasions, and not doing it on others might perhaps narrow down the issue to a specific part or component?

 

[ShortBtwnHdset]

If tube heaters glowing, that elimates only low voltage tube heater issues. High Voltage rail for tubes could still be culprit.

The relays clicking, that may only happen when relay is activated. Relay is powered, a magnetic field developed, then it literally overtakes a tiny springs pressure to activate the contacts. Shutting relay off may not be an audible click, as magnetic field collapses and eventually loses battle with tension counterforce spring. So, soft start relay seems to be working, and high gain/low gain switch seems to be working. Next place to go is have someone check bridge rectifiers and voltage rails.

 

[c0rp1]

If tube heaters glowing, that elimates only low voltage tube heater issues. High Voltage rail for tubes could still be culprit.

The relays clicking, that may only happen when relay is activated. Relay is powered, a magnetic field developed, then it literally overtakes a tiny springs pressure to activate the contacts. Shutting relay off may not be an audible click, as magnetic field collapses and eventually loses battle with tension counterforce spring, so maybe no hard click.

Another thing that I just noticed - actually there is a click when switching from high to low gain with regular tubes. But the click happens the same time as pressing the switch with no 15 seconds of wait time (I couldn't hear it at first due to the mechanical sound the switch itself makes). Still, there's no click when powering on the unit with regular tubes and gain set to low.

Why would the unit react differently with LISST and regular tubes though?

 

[ShortBtwnHdset]

If tube heaters glowing, that elimates only low voltage tube heater issues. High Voltage rail for tubes could still be culprit.

The relays clicking, that may only happen when relay is activated. Relay is powered, a magnetic field developed, then it literally overtakes a tiny springs pressure to activate the contacts. Shutting relay off may not be an audible click, as magnetic field collapses and eventually loses battle with tension counterforce spring, so maybe no hard click.

Another thing that I just noticed - actually there is a click when switching from high to low gain with regular tubes. But the click happens the same time as pressing the switch with no 15 seconds of wait time (I couldn't hear it at first due to the mechanical sound the switch itself makes). Still, there's no click when powering on the unit with regular tubes and gain set to low.

Why would the unit react differently with LISST and regular tubes though?

The warm up relay is timed to do that, the relay switching on once the relay is powered up is almost instantaneous. It's timed so that the amp circuits stabilize before output is routed to the headphones, otherwise you could hear Pops and other nasties. The gain switch relay should again switch ON almost instantaneous after powered, off will likely be soft for both. Now that you mention it, you did have a volume change using the gain switch, so that likely is working as well. With LISST tubes, solid state shouldn't take nearly so long to stabilize, so maybe Schiit accounted for that in the timed relay.

The voltage rails from the tramsformers go immediatedly to a bridge rectifier for each rail to convert to DC, then to a CRC network (capacitor/SMD resistor/capacitor) for filtering that DC (coarse filtering), and then to some sort of regulator or comparator circuit for fine voltage regulation. What is easiest to check for are the bridge rectifiers, but the problem could just as likely be after them, for instance in the regulation stages. That the problem is as you described would lead me to suspect the HV rail, so I would check it's bridge rectifier first. While I was at it, I would check the other bridge rectifiers at the same time. That can be done with a normal DMM as long as you drain the voltage from all the power rail capacitors before starting measurements. So drain all those first (look up a method on web), once that is done it is safe to work on unit. Use the diode checker function of your DMM. Compare each bridge rectifiers readings, if they show the same in terms of resistance/continuity, move on. For the voltage rails that have easily discernable/discrete regulators (150V, 14V, 8.5V), check them next. Confirm, move on. Obviously, if you see burnt circuit traces and or burnt/discolored/swollen parts, thats a good place to start. My point is if your careful and methodical, you may be able to at least isolate to a section/rail/stage, or in best case scenario a component. That's pertinent data that may help you or someone else pinpoint problem.

Again, this is methodology, If you have any doubt about doing it, refer to qualified personel. That's the limits of my amatuer skills.

 

[c0rp1]

The warm up relay is timed to do that, the relay switching on once the relay is powered up is almost instantaneous. It's timed so that the amp circuits stabilize before output is routed to the headphones, otherwise you could hear Pops and other nasties. The gain switch relay should again switch ON almost instantaneous after powered, off will likely be soft for both. Now that you mention it, you did have a volume change using the gain switch, so that likely is working as well. With LISST tubes, solid state shouldn't take nearly so long to stabilize, so maybe Schiit accounted for that in the timed relay.

The voltage rails from the tramsformers go immediatedly to a bridge rectifier for each rail to convert to DC, then to a CRC network (capacitor/SMD resistor/capacitor) for filtering that DC (course filtering), and then to some sort of regulator or comparator circuit for fine voltage regulation. What is easiest to check for are the bridge rectifiers, but the problem could just as likely be after them, for instance in the regulation stages. That the problem is as you described would lead me to suspect the HV rail, so I would check it's bridge rectifier first. While I was at it, I would check the other bridge rectifiers at the same time. That can be done with a normal DMM as long as you drain the voltage from all the power rail capacitors before starting measurements. So drain all those first (look up a method on web), once that is done it is safe to work on unit. Use the diode checker function of your DMM. Compare each bridge rectifiers readings, if they show the same in terms of resistance/continuity, move on. For the voltage rails that have easily discernable/discrete regulators (150V, 14V, 8.5V), check them next. Confirm, move on. Obviously, if you see burnt circuit traces and or burnt/discolored/swollen parts, thats a good place to start. My point is if your careful and methodical, you may be able to at least isolate to a section/rail/stage, or in best case scenario a component. That's pertinent data that may help you or someone else pinpoint problem.

Again, this is methodology, If you have any doubt about doing it, refer to qualified personel. That's the limits of my amatuer skills.

This is indeed extremely helpful. Thanks again!

 

[AlPastor]

I'm getting no sound whatsoever coming from my headphones

I had a similar experience with a used Mjolnir 2 I recently purchased. I'm guessing it got a little tossed around in shipping. Sent it to Schiit for repairs and had it back in two weeks for a reasonable cost. I'd suggest sending them a note and getting an RMA process started. It's worth it if you plan on keeping it for a while.

 

[lupoal]

Hi,
I've seen some previous posts about ECC81... I've recently bought 4pcs branded Westinghouse (NOS NIB) but I'm unable to recognize the manufactuter... somebody here could help me?
here are some picts... thks in advance

 

[AuditoryCanvas]

Hi,
I've seen some previous posts about ECC81... I've recently bought 4pcs branded Westinghouse (NOS NIB) but I'm unable to recognize the manufactuter... somebody here could help me?
here are some picts... thks in advance

Westinghouse made their own tubes, and also cross branded tubes with Sylvania and RCA, but RCA usually had a box around the type designation stamp, so it's likely Westinghouse or Sylvania.

Looking at the getter construction, I'd guess late 50s. If you can find a stamp anywhere on the tube, that might give some clues. Also look at the base between the pins.

 

[JayDM]

For anyone who owns one of these, how is this in comparison to other tube amps? Does it have a warm, tub-ey signature? Or does it lean more towards a solid state? Any words on the way it h does staging?

Considering picking one up as a supplement to my other gear and hoping it would add a bit of that euphony/soften some edges.

 

[XMarsX]

My experience with it is it completely depends on how much money you’re willing to spend on tubes. Inexpensive tubes = solid state more or less. Golden Lions = hey there’s some tubey goodness. Amperex 7308s = yesssssssss.