telefunken tubes

[pucho812]

Not sure how long they have been at this but looks like telefunken(USA) is back to making tubes

HMMM.

http://www.telefunken-elektroakustik.com/products/tubes/

They also making a drop in replacement for those expensive vf14m.

http://www.telefunken-elektroakustik.com/products/vf14k.php

 

[jensenmann]

Another sellout of the Telefunken brand. The original Telefunken company had their tube factory in Germany. JJ has nothing to do with the original Telefunken company neither does Telefunken-USA. They pay license fees for the right to use the Telefunken-USA name for their products to the Telefunken - Licenses GmbH. The latter one being nothing else than a company who sells the Telefunken name.

 

[pucho812]

all true.

 

[ruffrecords]

This smacks of the 1970s European mistake in trying to match Japanese quality. They mistakenly thought they could inspect quality in to a product but it is really the equivalent of trying to make a silk purse out of a sow's ear. No amount of selection of JJ production is going to make them Telefunkens.

Cheers

Ian

 

[thermionic]

Although I totally agree with Jens' point that this is marketing-driven, and that no modern company can match TFK quality (according to Oli Archut, some of the metals used in valve production are difficult to obtain / have to be bought in impractically large quantities), I was pleasantly surprised to see that a JJ-tubed mix-amp that a friend designed delivered -95dB THD at its highest harmonic when connected to a calibrated FFT recently. Although I didn't measure noise or microphony, JJ must be doing something right to deliver -95 in a bus amp - wouldn't you say? (well, that and my friend's slide rule!)

 

[fazer]

750 usd for a non original vf14 amazing they are making an atemp at remaking. Lot of coin.  I worked at a studio that has two original 47's.  The difference  between the vf14 and the other with a nuvistor 6cw was breathtaking.  If they can do that it would be worth it.

 

[ruffrecords]

Although I totally agree with Jens' point that this is marketing-driven, and that no modern company can match TFK quality (according to Oli Archut, some of the metals used in valve production are difficult to obtain / have to be bought in impractically large quantities), I was pleasantly surprised to see that a JJ-tubed mix-amp that a friend designed delivered -95dB THD at its highest harmonic when connected to a calibrated FFT recently. Although I didn't measure noise or microphony, JJ must be doing something right to deliver -95 in a bus amp - wouldn't you say? (well, that and my friend's slide rule!)

Stated like that it does seem rather good. However, no level is mentioned and neither is a load. Both will make a lot of difference to the measured distortion. It is not that hard to achieve -95dB THD unloaded at low level using tubes. You don't even need a special tube to do it.

Cheers

Ian

 

[jensenmann]

I do consider JJ tubes as the best currently available. No need to pay premium prices for a long gone brand.
For my last few tube projects I chose JJs over the old german tubes I had available. It seems that in most markets the available old tubes are the leftover unusable ones which everybody with ears and/or measurement gear resells after checking out. JJs always turned out as very usable, at least the longlife versions I bought. I promised myself that I will stop that vintage tube thing and simply buy them new, after having spend lots of €€€ just for checking it out, getting firsthands expierience and then throw the old garbage away... hmm some of them... :

 

[thermionic]

It was 1v RMS into a 600R load. It's a valve 'opamp', wired as a unity-gain VE sum amp. THD went up when the load went to 300R. I didn't test it to destruction in terms of input levels - I just took a quick measurement. I thought -95dB into 600R to be a 'respectable' figure for a transistor stage and was pleasantly surprised to see you could get it with valves.

Having said the above, I wonder what it'd achieve with some TFK valves? My friend who designed the sum amp doesn't go overboard with the whole NOS thing. I think he gets the JJs from Watford, so I assume they're tested before despatch. 

 

[thermionic]

I do consider JJ tubes as the best currently available. No need to pay premium prices for a long gone brand.
For my last few tube projects I chose JJs over the old german tubes I had available. It seems that in most markets the available old tubes are the leftover unusable ones which everybody with ears and/or measurement gear resells after checking out. JJs always turned out as very usable, at least the longlife versions I bought. I promised myself that I will stop that vintage tube thing and simply buy them new, after having spend lots of €€€ just for checking it out, getting firsthands expierience and then throw the old garbage away... hmm some of them... :

I think my friend who's been designing valve gear for 30+ yrs will concur. He doesn't advocate spending $$ on anything - he was distinctly unimpressed with my new FFT analyser; "I can do that with my scope - why did you buy that?"

:- )

 

[ruffrecords]

It was 1v RMS into a 600R load. It's a valve 'opamp', wired as a unity-gain VE sum amp. THD went up when the load went to 300R. I didn't test it to destruction in terms of input levels - I just took a quick measurement. I thought -95dB into 600R to be a 'respectable' figure for a transistor stage and was pleasantly surprised to see you could get it with valves.

Having said the above, I wonder what it'd achieve with some TFK valves? My friend who designed the sum amp doesn't go overboard with the whole NOS thing. I think he gets the JJs from Watford, so I assume they're tested before despatch.

If it is a valve op amp wired unity gain then it will have plenty of NFB. I expect you could put any brand of tube in there and achieve almost identical performance. As in many good designs, its the topology not the components that determines the performance.

Cheers

ian

 

[pucho812]

I recently replaced some 6386 tubes with the JJ versions. Not bad all around and definitely a nicer price around 120.00(usd) vs a NOS 6386

 

[thermionic]

I recently replaced some 6386 tubes with the JJ versions. Not bad all around and definitely a nicer price around 120.00(usd) vs a NOS 6386

Interesting. Could you get a chance to look at performance on the AP with RCA vs JJ?

 

[pucho812]

I might be able to. Just need some RCA 6386's  I may be able to beg or borrow for such a task. I'll see what I can do.

 

[sodderboy]

It's mechanics, physics, chemistry, and metallurgy. We all probably downloaded that 30's tube design book. You would think it possible for a tube manufacturer to copy the metals, mica, shapes, correctly scented vacuume, and re-create any tube. 
The trend over time has been to achieve the same performance with less material for all things electronic so if it looks different I would expect the same performance but not same sound.
Mike

 

[PRR]

> telefunken(USA)

This is self-contradiction.
________________________________

> -95dB THD

0.002%

A single naked tube can do 5% near clipping. Assuming 300V supply, clipping is near 60V peak or 40V RMS. So 1V will tend to be 5%/40 or 0.13%.

To get -95dB or 0.002% we need another 62:1 or 36dB of NFB.

A high-strung 12AX7 approaches gain of 62 in one stage. A multi-stage or Pentode amp would do a lot better.

OTOH a 600 Ohm load requires a BIG output bottle or a transformer.

Given big hammers, I have little doubt that a "loudspeaker amp" could be crimped-up to deliver -95dB THD at 1 Volt into low-Z loads. I had a Fisher 2*7189 amp which could be strapped unity-gain, and with high idle current might beat 0.01% at 1V into 16 Ohms. I would not want a stereo pair under the desk (except tonight when it will be very cold).

-95dB THD does suggest that many-many "minor" corruptions have been foiled sucessfully, good show.

 

[CJ]

good read on NOS quality,

https://web.archive.org/web/20131122142039/http://www.jumpjet.info/Pioneering-Wireless/eMagazines/VTV/VTV19.pdf

 

[thermionic]

> telefunken(USA)

This is self-contradiction.
________________________________

> -95dB THD

0.002%

A single naked tube can do 5% near clipping. Assuming 300V supply, clipping is near 60V peak or 40V RMS. So 1V will tend to be 5%/40 or 0.13%.

To get -95dB or 0.002% we need another 62:1 or 36dB of NFB.

A high-strung 12AX7 approaches gain of 62 in one stage. A multi-stage or Pentode amp would do a lot better.

OTOH a 600 Ohm load requires a BIG output bottle or a transformer.

Given big hammers, I have little doubt that a "loudspeaker amp" could be crimped-up to deliver -95dB THD at 1 Volt into low-Z loads. I had a Fisher 2*7189 amp which could be strapped unity-gain, and with high idle current might beat 0.01% at 1V into 16 Ohms. I would not want a stereo pair under the desk (except tonight when it will be very cold).

-95dB THD does suggest that many-many "minor" corruptions have been foiled sucessfully, good show.

Ok...confession time. My memory is less than great. It was into a 10K load - not 600R... (I discussed it with my friend after posting here). I remember (if you trust me...) that the increase was minor-ish when 600 was switched in, and harmonics really jumped up when the 300R load was switched in.

My friend is a proper old-school tube circuit designer, though. You should've seen his face when I recently gave him a graphing calculator that my girlfriend found in a drawer -  he was made up :- )

 

[PRR]

> my girlfriend found in a drawer -  he was made up :- )

Must be British. Here that phrase would lead to lipstick and mascara.

> a proper old-school tube circuit designer
> I recently gave him a graphing calculator

Old-school? Many fine designs were done with a slide-rule, maybe not even that. I spent some time that way before I built the $99 Sinclair 4-banger calculator kit. Screwed-up, it wouldn't display any "7"s, though I learned to work around that. Soon TI introduced a "scientific" LED pre-made for not a lot more. Still have one, though LCDs avoid the annoyance of finding the re-charger halfway through a hot session. Had a grapher, didn't understand it, I have eXcel if I really need to draw myself a picture.