Consider that I have various Telefunkens 12a types that are 60’s vintage
made for Fisher by Telefunken that are as wonderful today as they were
over 60 years ago.
The Fisher receiver no one knows the countless hours left on due to forgetfulness
by the owner. Nonetheless strut their stuff as if factory fresh are super quiet no hiss
even at full volume with my ear up against the tweeter…The sound quality alone
is superb…and that up against many highly regarded NOS.tubes.
If you look into the history of Telefunken you will see why this is so…
Question here, I mistakenly put two 12AU7 in my BHK250 and listened for about an hour before realizing the mixup. Would this cause any damage to the amp with their higher gain? I did notice a pop from the speakers when the amp was turned on and off with the 12AU7s in it. Thanks.
The pinouts are the same on the 12au7 the only difference being the heater voltage. The fact that you put a 12 volt tube into a 6 volt circuit you should be safe. The converse could definite cause an issue. The amp should have failed to start up with those tubes in it though.
Thanks for the input. Yes, the amp did go into fault mode when it was first turned on with a pop and the blue PS Audio logo flashing. But after pressing the logo button to turn it off and then back on, it worked and did sound pretty dull.
With the my BHK 250 tubes nearing a 1000 hrs, it was time to order some new tubes, but before I did I came across some Amperex 6922 I had lying around and decided to give them I try, I’m glad I did. These tubes seem to better the stock Genalex Russian tubes I purchased from PSA in every way. For one they sound more neutral, and less tubby, providing a more accurate and lively presentation. The Amperex also exhibit greater transparency and detai, but without sounding etched or bright. There’s also better extension at the frequency extremes, along with greater bass Impact. Soundstage width and depth have increased slightly, along with better image specificity. Lastly, Instruments and vocals sound more solidly anchored within the soundstage.
You just neatly encapsulated the difference between Amperex NOS/ANOS or just plain used and even good/very good current production tubes in the 6DJ8 family.
Now that these tubes have warmed up they sound even better. Can’t believe I didn’t try them sooner. I bought these as used old stock and used them in my previous Ayon CD player. I just assumed they were past-their-prime. Boy was I wrong, these sound glorious!
Never wanted to get sucked into the neurosis of tube rolling, but now that I hear how much these tubes have elevated the sound of my system, I’m afraid I’m hooked.
Sitting here shaking my head. The textures, tonality and organic sound I’m getting with these Amperex tubes is intoxicating. Don’t think I’ll be getting much sleep tonight.
Could you share the vintage and source for this tube? I tried ‘70’s Mullards on the BHK pre and found them bass tubby and dull vs. the stock Genelec. I’m going to get new tubes on the 300 monos and your new oldies intrigue me.
I purchased these quite a few years ago and I don’t remember what vintage they were, plus when I just installed them, I noticed most of the print was badly faded. I purchased them locally here in Denver from Vacuum Tube Supplies.
303-534-5170
I’ll look for the receipt. Hopefully it will include some details on the vintage.
I looked in the one place the tube receipt should’ve been, and no such luck, it wasn’t there.
Tomorrow I’m going to pull the amp off the rack again and have a closer look. I would also like to know what vintage these tubes are, because I’d like to order another pair.
I’ve found that sometimes breathing on the tube (like you would on a windowpane to fog it) will reveal characters near the bottom of the tube that are almost invisible.
Also this web site is useful in deciphering the codes for Philips (and Siemens) tubes. They omitted the location code for the Amperex plant in Hicksville, NY. The code is an asterisk * That plant produced Amperex tubes for the US Military such as the 7308 which by regulation had to be made here in the US.
I’ve just added a BHK 250 Signature amp to my growing stable of components. I have the luxury of being able to swap in and out a BHK 250 with my beloved Pass X250.5 any time I get the itch for one or the other. After listening to the BHK 250 with the stock reissue Gold Lions, in went a pair of NOS 1960s Telefunken 6922s. Out went some of the tubbiness others have reported with the Gold Lions, in came the top to bottom neutrality, dead quiet background, killer dynamics I’ve come to expect with vintage Tele’s. Wow. They’re freakin’ expensive and hard as hens teeth to find nowadays, I have two tightly matched pairs. That era of the mid to late 60s yielded some of the finest small signal tubes that will ever be produced. The BHK 250 eats them up. I purchased them from TubeWorld, btw. Extremely reputable. Pictures of the actual tubes you are buying are posted. Measurements of each half of the triode also posted. Great source for NOS glass.
I assume you don’t mean short lifespan. I’ve had telefunken’s and now mullard’s. I get a crazy number of hours on tubes in my 300s. These tubes might cost a mint these days but I get a lot of life out of them.