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
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 :).
@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 :).
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
I have only seen the on eBay.
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.
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.
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.
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.
