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Tube Rolling My Nighthawk MK3  

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RavenDave
(@ravendave)
Founder of Raven Audio Admin
Joined: 2 years ago
Posts: 71
08/09/2020 10:23 am  

@allears4u

Those pictures were taken with old GE 6550's stuck on them because we found ourselves without any 6L6GC's at the time.  They were originally taken at RMAF I believe, and we had those amps on display and I filled the additional amps with loose 6550's I had in one of the show boxes, so they wouldn't be bare chassis, and James took a picture of that chassis, and it became a website picture that we simply haven't gotten around to changing out. 

Most people (a few have though!) haven't noticed that.  YOU CANNOT use 6550 power tubes in the Avian Series amplifiers.  However, we do have a few alternatives for you should you be interested.  So contact me if you are...  and read my last post above for some alternatives to the OEM 7581A's that are usually warmer if a little less delineated, perfect for old jazz records and horns.  Of course the best power tubes ever made are the RCA black plates from the 50's through the 70's.  Nothing quite comes close, but they are hugely expensive, especially for authentic NOS or slightly used, NOS testing properly matched quads.

I am always available for inquiries about tubes for your Raven Audio amplifiers.  Always!

Dave

Blackhawk MK3 a
Nighthawk MK3 a
Nighthawk MK3 live
Osprey Burn In SM
GE Pink Base Matched Quad 2
RCA 6L6GC 50's

 


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Scotty
(@scotty)
Active Member
Joined: 5 months ago
Posts: 16
09/09/2020 5:19 pm  

allears4u:

I just want to echo what Dave is saying about the Chinese 6L6GC. Dave sent me a nice quad to try - but we were both unsure exactly what they were. After scratching our collective heads for a while, we found out they are

20200811 184608

early Shuguang 6L6GC's.

In my Osprey they were beautiful in appearance (see photo), really lighting up the room with the coke bottle shape and the nice glow at the top. They came across as dynamic with a certain gravitis - very nice. A little more research determined that they are reliable and well regarded.

The vintage RCA 6L6GC blackplates are the king - there is just something magical about them - but the Shuguangs are certainly a viable alternative for about a third the cost. In my system (HTPC>PS Audio Directstream DAC>Raven Osprey>Harbeth P3ESR speakers) in a studio near-field setup, they came across as very nice, and a little better than the TungSol 7581a.


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 12 months ago
Posts: 28
27/09/2020 4:19 pm  

Earlier in this thread both Dave and Scotty discussed some Shuguang power 6L6GC power tubes Dave had come across. Recently Dave also sent me a set of the Shuguangs for evaluation in my system, which consists of a Blackhawk MK3, Corvus Towers, mostly Soniquil cables, an Antipodes DX2 music server and a Lampizator Atlantic DAC. I also have 3 other very high quality sets of 6L6GC tubes, including the stock Tung Sol 7581A’s, the Svetlana Winged C’s, and the RCA Blackplates, so am set up pretty well to make an evaluation, at least as to what I hear from the Shuguangs as compared to the other three.

To set the stage, I have always liked the way the Winged C’s sound, and have been using them for several months, mostly swapping out preamp tubes here and there. Two or three weeks ago I believe I had some Valvo’s in R1, (Dave’s favorite) Yellow T’s in R2 and some Cifte 12AU7’s in R3. The system was sounding as good as I had heard it. About then I was chatting with Dave about tubes and he brought up some Hytron 12AU7’s he said were spectacular, as well as some very special Tungsram 12AT7’s. I said I would like to try them and in a few days here they came. I didn’t have super high expectations that I would hear anything that much better or different since I already had a lot of Dave’s most highly regarded tubes. The first change I made was to replace the Cifte 12AU7’s with the Hytrons. To my surprise the overall sound was significantly better. That was a first for me when dealing with R3. So I stayed with that setup for a couple of days, then replaced the Valvo’s, one of my favorites, with the Tungsram, and the sq took another jump. Now we’re talking relatively small, but to me at least very discernible jumps. Enough to convince me that as long as I have my Blackhawk I want to have a set of each of those tubes.

At this point I kind of figured I had pretty much hit the ceiling on what the Blackhawk was capable of putting out. Little did I know!

The next thing that happened was Dave was talking about how much he loves the RCA Blackplate power tubes, so I put mine back in because it had been awhile and I wanted to revisit their sound with my now fully broken in Towers. I was rewarded with at least as good or better sound, depending on one’s tastes, as I had with the Winged C’s, so had planned on leaving them in for awhile. But as fortune would have it I was talking to Dave again, and he asked me to check out the Shuguangs, which have now been up and running for several days, resulting in the following tube configuration:

Power: Shuguang 6L6GC

Row 1: Tungsram 12AT7

Row 2: Brimar Yellow T 12AT7

Row 3: Hytron 12AU7

First of all let me say the Shuguangs are quite different in appearance from the other power tubes I own, and are in my view very cool looking, due to their brightness, especially at the top. I also like the coke bottle look. But similar to speakers, looks are one thing, but performance is what counts, and  these tubes excel in both.

When I inserted these tubes I expected something akin to the Tung Sols, Winged C’s or even the RCA’s, what I got was something (in my estimation) altogether different and better than them all. The first thing I noticed was a lowering of the noise floor, resulting in greater clarity, a greater sense of vocalists’ presence in my room, increased dynamics, and more volume at the same setting on my amp. I am hearing even more micro detail than before - before being truly exceptional compared to other equipment I’ve owned. Increased detail can sometimes come at the cost of tonal sterility etc, but I don’t discern any of that. They are very similar to the Corvus in that regard, ultra accurate but still sweet and warm.

Following is an example of the increase in clarity I have experienced. In my review of the Corvus a few months ago I mentioned a Ray Bonneville song titled Night Walker and how I had a sense of being there with the singer on his balcony or whatever, but there was one word I could never figure out. That song happened to come up in my playlist, and suddenly I knew what the word is. I called my wife over and told her, “listen to this, I finally figured it out, it’s silhouette!”. In fact I think she said the same thing as I was saying it, it was that clear!

Another example is not a song but an instrument - that being the cymbals, which are clearer and sound more like real cymbals. Cymbals are always a litmus test to me of sound quality, accuracy etc., and I tend to focus on them at times when I listen. It amazes me how many songs have quiet cymbal brushes in the background and how easy it is to miss them or not even hear them at all. With these tubes the cymbal brushes are showing up in songs more than ever. Since I’m talking percussion I should mention the snare drums have suddenly taken on more prominence with greater realism - not an instrument I normally pay attention to or pick up on.

I mentioned above the increase in volume and dynamics. When I turn up the volume the sound doesn’t seem louder as much as it seems clearer and more involving. In fact I have to be careful turning it up because one of my ears can ache with too much sustained volume, and I started feeling some of that because the volume doesn’t seem as loud as it really is.

There is more I could discuss but I will conclude by saying, and this may come across to some as hyperbole, to me the improvement in sound is akin to having upgraded my amp. Not to the level of an Elite Raven amp I’m sure, but definitely in that direction. I obviously can’t guarantee others will experience the same improvements in their systems with these tubes because everyone’s setup is different, but they are definitely worth taking a look at if more become available. I do know the ones I have are not going back, no way no how :).

 

 


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Scotty
(@scotty)
Active Member
Joined: 5 months ago
Posts: 16
29/09/2020 5:53 pm  

Greg - thanks for that informative update. Your Power Tube experiences inspire me to move the Osprey (temporarily) to the big rig for a trial. The configuration in the larger room would be: Mojo Audio Deja Vu Music Server > Mojo Audio Mystique V3 Dac > T+A PDP 3000HV > Raven Osprey MK3 > JMR Orfeo Jubilee Speakers for a trial 6L6GC shootout -the RCA Blackplates vs the Shuguangs.

My current tubes layout:

Power: RCA Blackplate 6L6GC

R1:      Brimar Yellow T 6060/12AT7 (Dave #1)

R2:      Mullard CV4024 (I like these a little better than the Tunsram ECC81s)

R3:      GE 12AU7 Green Print ladder plate (Dave #29) (prefer over the RCA 12AU7 Black Plates)

In my small, near-field studio rig, described above....it is pure velvet.

So, I look forward to trying the Shuguangs in the larger room to see if I experience the same audio bliss that you did. I cannot imagine it, since I am hearing through the RCA Blackplates a beautiful engaging refinement that is just magical. Probably won't be able to get to it until this weekend.


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 12 months ago
Posts: 28
29/09/2020 11:35 pm  

@scotty

Yes, it would be nice to have some additional validation because I think the Shuguangs would be a great tube to include as an option for new owners and Dave has an opportunity to acquire a couple hundred more of them. He and you are in sync when it comes to the RCA’s, so if both you and he both see the Shuguangs as being at least in the same league as them then they are quite a find. Also, I just happen to have the same preamp tubes as you running right now. I have a set of the Mullard CV4024 (3 Hole) in Row1, YT’s in 2 and GE Ladder Plates in 3. Dave recently sent me the GE to evaluate. All these great tubes really make my amp sing :). 


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RavenDave
(@ravendave)
Founder of Raven Audio Admin
Joined: 2 years ago
Posts: 71
30/09/2020 12:18 am  

I am just so happy to see you guys getting so much enjoyment out of your Raven Audio systems.  The great old tubes are just more icing on a great cake~!  I will continue to look across the world for more burning glass gems.  It's just so incredible to think that most of these tubes were made so long ago.  I think even the Shuguangs are a few decades old.  Scotty will probably let me know more on that though...  he's a great online detective...   c):{

DT


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mikeknj
(@mikeknj)
Active Member
Joined: 7 months ago
Posts: 10
30/09/2020 1:55 pm  

I have only seen the on eBay.


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Scotty
(@scotty)
Active Member
Joined: 5 months ago
Posts: 16
06/10/2020 3:03 pm  

Greg – I finally got some free time to move the Osprey MK3 into the big rig (easy task thanks to the thoughtfully provided handles) for an A/B shoot-out of the power tubes (RCAs vs the Shuguangs). I found that the Osprey’s 30+ tube watts drive the JM Reynaud Orfeo Jubile’s (91db sensitivity) very easily – my listening session never exceeded 9:00 on the Raven's volume knob.

As I said before, in the near-field intimate studio rig (see above for details), I preferred the RCA Blackplate 6L6GC power tubes over the Shuguang 6L6GC. To my ears, the RCAs offered better refinement, detail, and a more engaging listening experience. By the way, the Shuguangs I used are the coke bottle style. My understanding that newer Shuguangs are not this style. I am not sure of the manufactured age of the tubes, but they appear to be new.

I fully expected the RCAs to be superior on the big rig, but to my surprise – I totally agree with your assessment in every point you made. I realize that this is may be an unpopular view, since the RCAs are considered to be the crème a la crème by many. The RCA’s lost some of their magic, and on some tracks I experienced some sibilance (mostly high guitar notes on Jeff Buckley’s Hallelujah, or high female notes). I define sibilance as a harsh, unpleasant experience on high notes, of which I am apparently particularly sensitive.  

The Shuguangs were overall more enjoyable, sweet and warm as you say – while still maintaining very nice crispness and detail, the sibilance I experienced on the RCAs was tamed and better modulated, and the magic was back! They produced a certain texture and and richness in a very non-fatiguing manner. Bass notes on both the RCA and the Shuguang were very deep, tight, and well-defined.

Add to that the beauty and unique lighting effects of the Shuguangs (it is not a subtle difference), and I think that Dave has a very nice option for power tubes on the Avian amps.

Dave has always stressed the importance of matching the tubes to your system, and I have found that to be true in my case: RCA’s for the small setup, and the Shuguangs for the big boys.

I would also like to note that the changes I have made to the preamp tubes as described before have made a big difference in the amp’s performance. I am very pleased with the Osprey in either room.


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 12 months ago
Posts: 28
06/10/2020 5:30 pm  

Thanks Scotty! I am gratified to hear you were able to confirm my impressions of the Shuguangs in your reference system. I’m sure Dave, Bryant and James will find your conclusions helpful when they consider power tube options for the Avian amps. 

7FA47F8C 134C 45CE 9B80 3B486B1F30BD

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Scotty
(@scotty)
Active Member
Joined: 5 months ago
Posts: 16
06/10/2020 8:40 pm  

Greg -

Those wall treatments are really cool!

How are you liking your Lampy Atlantic Dac?

I'm looking to upgrade, and seriously considering a Golden Gate 2 to replace my PS Audio Directstream with Snowmass.

I had an early Lampizator: Gen 3 Level 4, and loved it at the time. Unfortunately it had issues, and it is gathering dust in the closet. I understand they have now gone to circuit boards instead of single wired, and the issues are in the past - hope so.

Now, I am listening to the Shuguangs in my small rig and really enjoying them.

Thanks again.........Scotty


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 12 months ago
Posts: 28
06/10/2020 10:05 pm  

The Atlantic is great. Have never had any issues with it. It is one of the early ones without any of the upgrades they offered later. I imagine the Golden Gate would be a wonderful DAC. The wall treatments are my pride and joy because I designed the layout and somehow hung them myself - not very handy that way, but by golly I did it haha. 


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DRHamp
(@don)
Active Member
Joined: 7 months ago
Posts: 14
11/10/2020 1:22 pm  

I’ve had the Nighthawk MK3 since early this year and I’ve rolled a lot of tubes, some with great results and some not so much. I’ve been primarily focusing on Rows 1 and 2 and the various 12AT7 combinations and have found many excellent choices.

I hadn’t paid a lot of attention to Row 3 until recently. The MK3 was delivered with a pair of RCA Clear Top 12AU7s and fairly soon thereafter, I purchased a pair of early 1950s CBS Shiny Black Plate 12AU7s from Dave and they were a major improvement and became my “Standard” for Row 3. I rolled several other pairs into Row 3 but they never quite measured up to that CBS pair – until very recently.

I had in my stash, probably 20 to 30 12AU7 matched pairs that I’ve had for a number of years that I had used in previously owned tube amps.

One pair and the impetus for this post is a pair of RCA 5963s with Black plates and a Slanted square getter. The 5963 was intended for digital circuit applications and were used extensively in the Univac computers and NORAD systems. They have a reputation for being noisy and aren’t generally favored for audio applications.

Maybe it’s my aged deteriorating ears but these rival and maybe surpass my previous standard, the 50s CBS shiny black plate 12AU7s. I have at least six pairs of these and none of them exhibit any noticable noise.

There are at least two (maybe more) examples of 1950s RCA 5963s. The two I see most often are the ones with the slanted square getter (1st photo attached) and the other is with a D getter on a tall post(2nd photo attached). The one with the slanted getter is the one I’m talking about. The D getter on post version does not sound nearly as good to my ear.  Why that makes a difference, I have no idea.  The one with the slanted getter seems to be attached right at the top mica and not on a post.

RCA BlkPlt SlantGet
RCA 5963 Dget  on post

I see both versions pretty regularly on Ebay and I believe I’ve seen one with a top O getter but not sure about that. These are typically $35 - $45 per matched pair so, not so expensive and maybe worth a try.

Just thought I'd throw this out to those who may be interested.  


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Scotty
(@scotty)
Active Member
Joined: 5 months ago
Posts: 16
11/10/2020 3:35 pm  

Don - thanks for sharing your experiences on Row 3. I am currently enamored with the GE 12AU7 Green Print ladder plate (Dave #29). 

Here is what Brent Jessee has to say about the 5963:

"5963: This is a nice industrial type which is nearly identical to the standard 12AU7. RCA made a nice blackplate version of this tube, Sylvania has a gold pin version, and GE has it in their 5-star broadcast line. The plate voltage rating is a little lower than for a 12AU7, but for most applications, it will work fine. It has a rugged cathode and should be long lived, similar to the 5814. Watch this tube, as it is plentiful now and prices are low. As audiophiles discover it, the rush will be on!"

I see that he has several versions available, so I might try a couple of pairs - probably the RCA Blackplate and the JAN Sylvania Gold Brand.and 


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