ampsandsound (aka Amps & Sound)

Fair enough. I've just found in my own listening that even cheaper vintage tubes seem to outperform more expensive currently-manufactured ones. It's not a snobby thing; I just haven't heard any that I really like yet

 

It depends a lot on the tube and type. The JJ 6CA7 are noted for being very full and a little dark. That is absolutely true. They sound good overall. I have an Apex Matched pair of them, so the balance is probably responsible in part for how good they sound.

However, they're very tube-sounding and are a bit soft and lack a bit in detail. They're a very easy listen for extended periods and are quite musical, but if you're looking for clarity and audiophile words, they largely lack in that department.

But...

I did a lot of looking into tubes that will fit into the Mogwai. I have a bunch on the way, but I received some new production tubes last night.

The JJ KT88 tubes are said to be very good from all of the reviews I've read. They're also pretty inexpensive. The Tung-Sol 6SL7 is the best current production of that type as well. I grabbed both.

The JJ KT88s are also Apex Matched (which I've found to not be a load of BS, by the way--they're legitimately very well-matched). These tubes are absolutely excellent.

They're great with detail retrieval and clarity but don't have any of the treble peaks of the Svetlana 6550C NOS tubes. After looking into it more, I think the 6550 tubes in general are known to have that upper midrange peak that is bothersome to me personally (but I'm especially sensitive in that area--to most, that's probably a good thing).

I'm really digging the JJ KT88 and I've quite happy with the sound either with the new Tung-Sol 6SL7GT or the old badass GE that I also have.

Also on the way are some new production Sovtek 5881s, a 6P3S-E NOS tube, 6N9S Melz tubes, and a couple others. I tend to really like the old Russian military stuff (in part for its tone, in part for its value). If it outdoes the new production tubes, I'll switch and buy up a bunch.

 

By the way, here's Gizmo with the new production JJ KT88 and Tung-Sol 6SL7GT:

 

So the Mogwai uses 6SL7 and the Kenzie uses 12SL7?

It's not very clear on the a&s site...

 

Yeah the input tubes are a little confusing according to the site.

The Mogwai uses 6SL7 in the middle socket. You can also use 7F7 tubes with an adapter (I have one on the way to try them out). The power tubes are basically any 6L6 variant up to KT90 or so (the KT120 might work, but they likely won't be pushed hard enough for optimal sound).

The Kenzie uses 12SL7 in the middle and 1626 in the power section.

During the review process, I'm going to encourage Justin to include a bit more information on the site.

For example, "6L6GC to KT88" doesn't mean much to a lot of us. A more definitive list of power tubes would be nice (e.g. 6L6GC, 5881, 7581A, KT66, KT77, KT88, KT90, 6CA7, EL34, 6550, 6N9P, possibly a couple I missed).

 

This makes the Mogwai more convenient for ZDS owners, as we (likely) already have a nice stable of 6SL7s. Does he ship with the KT88?

 

You could certainly ask him to. I got mine with a 6550 because that's what I asked for. I decided after the fact that I was wrong and preferred the KT88.

 

I could see this amp getting spendy post-purchase what with all the power tube variants. It'd be a lot of fun too. Go for EL34 to get that lush euphonic midrange, or KT88 for more balance and control, etc...

 

I have a lot of rock and metal in my library. I've found that compared to my previous HA-1, the "leading edges" so to speak are just slightly less sharp on the Kenzie. Not in a bad way, just different from solid state. It might also have something to do with the current tube configuration. My 2C52 tube is on the way from Justin, so I'll be able to compare soon (too bad I'm away on business all next week). He describes it as a "holy grail" 12sn7. I'll be checking out some other 1626 power tubes as well

 

Quick update: Justin updated the Amps & Sound website with more information on both the Kenzie and Mogwai. I updated the original post as well. It gives more info on the specs and compatible headphones and tubes.

 

A few pics of the Kenzie amplifier (and Justin).

 

Decided to plug into the Project Horizon after a week with the Mogwai. I was honestly hoping to go, "Oh, I like this at least as much."

Good/bad: I definitely prefer the Mogwai. I was hoping my crap ears would decide that the Horizon was as good or better so I could keep it and eventually sell the Mogwai.

Nope.

 

Ah, tube rolling the Mogwai.

I've now tried these power tubes:

• Svetlana 8550
• JJ KT88 (New)
• Electro-Harmonix KT88 (New)
• Mullard KT88 (New)
• JJ 6CA7 (New)
• Tung-Sol 5881 (New)

The JJ KT88 are my favorites.

I've also tried the GE 6SL7(? Not actually sure which this one is), Sylvania 6SL7, Russian 6H9C/69NS Melz, Tung-Sol 6SU7, and Tung-Sol 6SL7 (New).

I think the GE is my favorite. Frankly, I can't tell as much of a difference between the 6SL7 as I can the power tubes. The Russian tubes are the brightest of the bunch, which sucks because I think they look the coolest. I was prepared for those to be my preferred tubes, but I can't handle much treble before my ears cry. Maybe with burn-in they'll smooth out a little.

I'm waiting on the 7F7 adapter I got from China to try one of those out.

At this point, I have two more power tube types on the way, but I'm guessing the JJ will come out top. One is a 6P3S-E from Ukraine/Russia, and another is a Preferred Series KT88 (new production triple mica made by Shuguang that is supposed to be very good).

 

How well does the Mogwai drive the HD800(S)? Only a handful of amps are known to make the HD800 tolerable sounding... would be interesting to see how well it fares against the likes of Torpedo 3, ZDS or Stratus in this regard.

 

Not sure, but I'd assume it does it very well. Someone who had a Kenzie loved the pairing. Given its ability to smooth the top end out and its tendency toward warmth and organic lushness, the Mogwai might even make the HD800 listenable for me.

 

how about bass impact on the mogwai/kenzie? With an hd800 for example.... =)

 

Tube dependent! I can't speak for the Kenzie, but for the Mogwai the JJ KT88 brings the bass pretty hard. It's my understanding that it compresses the bass a bit and lets you hear low sub-bass cleanly while being very powerful. Whatever it does, it can really pound.

Being the resident basshead, bass is one of the most important pieces to me, as is smooth treble and full overall sound.

 

Thanks for the feedback Luckbad! can it be used as a preamp?

 

Nope, the new "NOS" line are all DACs, they don't have any amps, volume control, etc.

 

I think you are talking about audio gd... I was asking about mogwai/kenzie... =)