Love the 6L6 in my rig...especially the 7581A.
DON:T WAIT! Replace Those Old Power Tubes!
For several years I've cobbled together the required quad of 6L6GC power tubes for my Raven Audio Integrated amp. I say 'cobbled' because out of two sets I culled four which would perform what I perceived as reasonably decent sounding. Being on the last best four I feared one more failing tube would put me out of the music. So, I ordered another quad from Raven Dave (Thomson). At first I thought to just saved them for an emergency but on a whim I decided to just put all the Chinese New Old Stock (NOS) in place. APPARENTLY, and obviously, my smorgasbord set in place previously had various quirks including but not limited to: hum, occasional buzzing, and a bloated`slow tone. My wife immediately stated: I don't hear anything in the background. Indeed there isn't anything but dead silence. NOS tubes are always a "Russian roulette" deal but their unique and amazing "real-ness" is worth the gamble. (IMO) So if you have been waiting until you absolutely have to, DON'T WAIT any longer. The improvement is profound. These tubes are as old as I am! Only difference is I've not been in a box traveling around the world for over 60 years!
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You say Raven Audio amp..What model do you have ?? I had Osprey for 5 years and was very happy but just months ago went with Reflection and I can not believe what my ears hear and have missed all these years in the music I have listened too.. I m running KT88’s and most of my music 90% sound beautiful but for the other music to sound good would need a tube roll probably to 6550 tubes.. If you can get them from Dave is Military 1970 6L6GC tubes these produced in Osprey the most amazing sound stage from that unit .But also 6414 talls in third row ,6060 yellows row 2 and Siemens ECC81 Row 1 ..The best sound that unit could produce.. The other power tubes I enjoyed was Tong Sol 5881 they had a warmer sound .. Dave can find some really nice tubes for his product line. |
I originally bought the Raven Nighthawk. Then, Raven Audio offered an upgrade to the transformers to toroidal, and an upgraded PC board, and other upgrades were offered so Raven recreated my Nighthawk into something better. I'm unsure what to call it now! I had read your earlier post about the Reflection. It sounds totally amazing. (And it looks incredible!) These Chinese NOS are a bit pinched up but soon will open up I expect. The quiet background is beyond anything I've ever heard on my amp from the very first day. After just getting my sub issue worked out, and now these new power tubes, it will be hard to get anything done around here. LOL |
I went from dual SVS SB10's to a single SB16 and the sound of single sub over my duals is so much improved that it has more real depth and trying to find positions of duals just drove me ..I am running the Raven Audio Corvus speakers very pleased with them..Enjoy your system and once in a while get off couch.Happy New Year |
Once you decide to stick with tube equipment, I advise keeping an eye out for a decent tube tester. Knowing their relative strength and testing for shorts, that is way beyond the world of darkness that you live within without any kind of testing ability. I check all my tubes routinely twice a year, and have the benefit to check, know their status when I buy them new or used ones I find or friends give me; or whenever any issue pops up, like the imbalance I just traced to a poor connection of a cable that never gave me trouble before. Today I am changing the connectors to these compact ones, see the video Tight RCA Connectors, screws, no solder needed
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“ Chinese NOS “ ? That’s a new one to me, but I don’t get out much. A tube tester is a must have. Not owning one, I utilize a neighbor that’s in the local radio club. As far as NOS , I prefer them for input, and rectifier positions. In regards to power tubes I have NOS, Current Production, and 1 set of higher quality Chinese. I find new production Gold Lion and Tungsol nice. But to your original statement, with power tubes being a wear item, putting in fresh tubes is almost always a realization of how worn your current ones are. The only tube failure I’ve had that actually caused damage was a brand new Gold Lion KT-77 that failed and damaged my amp. |
Yes a tube tester is on my short list of "important" items needed. Honestly that level of commitment was what I feared originally about tube equipment but despite myself I'm overcoming my xenophobia. The quality of musical reproduction is so "human" that I'm getting braver and beginning to embrace the cool details of tube design and magical sound quality. I'm so techno-phobic that tubes seemed unnecessarily demanding. But, contrary to my stubborn comfort zone addiction, I've begun to embrace the additional knowledge set that tubes require. "Old dogs new tricks" adage rings true for me except gaining amazing music quality beyond anything I've ever thought I could own has lead me down a path which contained delights worth the uncomfortable feeling of uncertainty. Yes, Chinese NOS which, I'm reliably informed, far out performs current production models. Not cheap though at $400 per quad for Raven Heads through Raven Dave of Raven Audio but my ears have never experienced such a treat!!
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I agree with Elliott. I test all tubes before they go in my gear for shorts and Gm. Even then it's no guarantee. I bought a tester and few years ago when I started playing with rectifiers and DHT tubes . It wasn't cheap but it saved me from putting what was no question a bad NOS tube in my amp. I bought 6 of the same tube, same JAN box, lot # etc but there was a bad one in the mix. My failed tube count over the past 25 years is low but I wish I had a tester years ago. It only makes sense if a number of components are tube, but it is valuable when you have a problem. |
I have a Hickok 800 , it seems pretty accurate with a few tubes that I have that were matched on a modern Amplitrex tester. Sure it's great to know how strong a tube is but it is far more important to check for shorts and gas. I was lucky, the one I picked up looks like it was in a museum. It was serviced a few years ago and gives consistent readings. Not usually the case with old testers. |
@oddiofyl that's right, testers are great for weeding out shorted or bad tubes, not so much for tube life or even for matching. Testers don't test tubes at real world operating voltage and current. |
Some testers, like the Amplitrex, do test at full power and do give one an idea of how much life is left in the tube. This tester, if attached to a computer, will curve trace the tube. Someone who owns dozens of modern and vintage testers told me that he likes the E-Tracer which is bought from Taiwan as a kit; it too curve traces and delivers very close readings to the Amplitrex. Another supposedly good tester/tracer that comes as a kit is the Sofia tester. A local shop uses a TV7 tester as its main unit. It is good for finding bad tubes and weak ones, but, it tends to be a bit generous in its rating—it will give strong readings for tubes that the Amplitrex says is not that strong. This shop also uses a modern, very compact tester called the Orange, but they mainly use it for small signal tubes. |
The Raven Audio amps seem to be tough because due to my overuse of nano contact enhancer on tube pins I shorted out, red plated a couple power tubes. Very scary when a tube glows bright red in the main body of the tube and a horrific howl blasts from one's speaker. Being a complete novice and never even knowing about or ever seeing such an event I was both terrified and intrigued. Immediately put it off. let it cool, removed offender and "kept calm and carried on". (All nano enhancer has been cleaned off now on tube pins TIP: Use sparingly, extremely sparingly) Occasionally a tube would begin to "red plate" I will shut off unit, reseat tube, and it will act normal again. But as I said, these amps can withstand a lot of user misuse.My normal idea of learning by experience may be on my tomb stone. "Experience Is The Perfect Teacher to He Who Lives Forever" (For mere mortals, read the instruction book) |
@allears4u Do Raven amps still use tube sockets mounted directly to the circuit board instead of being mounted on the chassis? If you are doing a lot of tube rolling, you may have cracked solder joints causing operating failures like you mention. Intermittent red-plating should not be happening as if it was a matter of course. |
I'm not sure how the tube sockets are attached but after I cleaned off the nano contact enhancer which can move around a little with heat and getting these NOS power tubes no more problems with any thing. As usual its my fault for over using the nano stuff and being too cheap to just get new power tubes which I suspected I needed for a while. (Didn't;t realize just how much I needed the new tubes) AND, I was always changing around tubes to discover the best sound with each combination. So intriguing to hear the changes as I try different preamp tubes especially from all around the world and from different time frames of manufacturing. All NOS in this amp. If anything could crack I surely would have cracked it by now. Did have one of the 9-pin tube leave behind one of its pins before and I shoved another right along side of it! Iy played but was a little weird so I checked to discover the extra pin lodged in a slot. Not good. Raven Dave is sending a free replacement as if he's personally responsible for all things Raven Audio which I appreciate endlessly of course. May I say Raven Audio (as many here have confirmed) is profoundly committed to personal customer care. Chris Botti CD playing right now beautifully. Over and out |
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