 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
68.37.17.199
Every time I try a tube marked 6201 it lacks bass. But a standard 12AT7 is perfect. I thought they were the same tube type???SO what really IS the difference.
charles
Follow Ups:
I'm a little out of the scene now but several months ago found the Telefunken data sheet for ECC801S/6201. I can't compare the sound or specs to any others but put some of the design info here figuring ya'll might be able to fold it in with other info.For Reliability they say: "The factor P indicates how many of 1,000 tubes fail over an operating period of 1,000 hours. The figure is approx. 1.5% for each 1,000 hours."
For Long Life: "we guarantee 10,000 hours operation averaged over 100 tubes"
Tight Tolerances: "In these tubes the tolerances of electrical ratings are reduced in comparison with receiving tubes."
Vibration and shock proof: "The tube withstands acceleration of 2.5 g at 50 c/s for lengthy periods and momentary shocks of 500 g for short periods."
Cathode free from interface: "The cathode establishes no interface even in cases where the heated tube is operated without plate current over lengthy periods."
The tube satisfies the specifications in accordance with Mil-E-1/3D of typ 12AT7W.
Fran
"The truth is out there"
airtime,It must be telepathy that you bring this up as I was planning to post a long post concerning 12AT7s and variants. Once I have my new Telefunken ECC801Ss in hand, I'll do it.
My understanding has been that the 6201 has the same electrically requirements and outputs as the ECC81 / 12AT7 but has certain standards for ruggedness- in terms of capabilitity of quick and numerous on/off cycles, secondly standards for low self-noise and then low microphonics. often, I've heard of the 6201 referred to as an instrument (testers, medical, oscilliscope) or computer tube- that is, used when computers were tubed rather than transistored. The GE 6201 for some reason is more often called a "computer-grade" tube or the like. I think it is the on=off cyclew feature that makes this didfferent from the 12AT7WA.
6201s, to meet the challenges, are ususlly a bit heavier built and often have extra support rods to the plate structure and thicker or even triple micas. I assume the heaters and others elements are a bit beefier as well.
It is probably only incidental that the 6201 works as well as it does for audio. Some of these may seem to lack dynamics, but I think this may be due to the dead quiet background and the low microphonics that give an impression of constraint. I've never worked out the technical reason, but notice that the more a tube is ruggedized, the less lively it may seem to sound compared to other variants. I will invariably choose a 6DJ8 over a 7308 for sonics as an example.
It's interesting that you find 6201s bass-shy as I specifically like the old triple mica Five Star GE 6201 for it's bass and have used this one in my microphone preamp. What models have you triewd and where?
Recent 6201 tries: Currently, I'm using an amazingly good 6201. This is the Hamburg made Valvo gold pinned 6201- white labelled, with "Falcon" (- actually an "Adler" or eagle for German army issue). After searching years for the blue labelled (rugged, mobile designation), pinched waist Valvo, I am sorry I didn't try this one before. If this version is this good- the Blue series must be be unbelievable!
I've been using my favourite Siemens triple mica E81CC- a very elabroate structure with double gettter supports and the splatter shild above the plates, but the Hamburg 6201 has just an wonderful mid range and is detialed and smooth as can be. BTW, this one looks like a more conventional ECC81 with short plates and signgle support, but the micas are extra thick and there is a support rod for, the plate structure. The dynamics are not as obviously 'fast' as the Siemens, but really more refined and the resolution and 3D effect is outstanding. The mid-range matches the previous winner in that area, the Mullard M8162- which is a nice one itself. The sound is not surpisingly closest to the Amperex Bugle Boy ECC81 (both are Philips), but I think the Valvo 6201 adds an additional kind of authority to the BB sound. Clean and clear! A bit more lively than the Sylvania GB-6201 which is a very "low key" 6201. I've tried a lot of 12AT7 types, but may have to revise my order of preference. Thanks to tubemonger for bringing this one to my attention!
Cheers,
Bambi B
12AT7s at home:
USE 7> 2, 2, 1, 1, 1
Siemens E81CC- 3 mica- NOS
Valvo 6201- gold pins-Hamburg- NOS
Siemens ECC81- NOS
Mullard M8162 NOS
Sylvania GB 6201-steel pin- NOS
Sylvania GB 6201 gold pins- NOS
Amperex Bugle Boy-France- NOS
GE 6201 5 star- 3-mica NOS
RCA -HP- NOS
RCA 6201 2-mica black plate- NOS
Sylvania JAN 12AT7WA 3-mica 1958 -NOS
Sylvania 12AT7WA-GoldPrint- 3 mica -USED
GE -NOS
Westinghouse- black plate-NOS
Telefunken ECC81- USED
Philips JAN- NEW
Telefunken ECC801S- NOS
Telefunken ECC81- NOS
Have anyone had any experience with these? They are rugedized versions of the 12AT7 M8134.
Hay anyone had experience with GEC A2900.
Is there a sinlge triode 12AT7/6201 alternative? I know the 12AX7 has some single cousins? Are they 7 or 9 pins types?
I'd be grateful foe som info.
Best wishes
DM
EC92 is a single triode with same characteristics as each section of 12AT7.
David Crittle
retrovox.com.au
The only two 6201's were a Sylvania GP and another that I could not get a brand marking. Overall even the cheaper EH and Ei's were better sounding all way around, even over a $50 sylvania. However I do have on order a GE 5 star, giving it one more try.The Sylvania had wonderful mids and treble. Truly velvet smooth but again the bass issue was a serious problem. And I'm not talking about listening to Rap level bass - this is low level classical music.
The application is for a Fully modded PAS with Curcio's boards. Wonderful, excellent preamp. And NOTHING like the original pas.
Thank you very much for such a complete explaination. I look forward to the posting you mentioned comparing the two.
thanks
charles
I recently built a 12AT7 triode front-end for a Dynaco MkIII. I tested about a dozen tubes with a signal generator and a scope, to see which tube gives the largest undistorted signal in this circuit.
The only tubes that passed this test were two Sylvania 12AT7. I had an "almost passing" RCA 12AT7. All the rest failed miserably, including two 6201. I should say that all these tubes are new and were tested for leaks and emmisions.
Maybe my sample is too small, but it sure makes you wonder...
Cheers
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]