Lundahl LL1517. What is it good for?

Tyimo · 23rd January 2009, 04:07 PM

Hi!

Could somebody tell me What is the LL1517 good for?
Is it possible to use in tube circuit?
Something like the Raven preamp has in the input?

http://www.lundahl.se/pdfs/datash/1517.pdf

Tyimo

ErikdeBest · 23rd January 2009, 04:15 PM

Hi

The LL1517 is designed to be driven from a very low source impedance. The datasheet even mentions 'minus 18' as the optimum source. The frequency response is given when driven by a source resistance of 10 ohms, fed into 600R. Those are too low values for tubes. Ok, a white cathode follower may achieve a R out of 10 ohms and not distort to much when driving 600R, but that is about it in the 'tube world'.

Erik

Tyimo · 23rd January 2009, 04:37 PM

Hi Erik!

I would connect it between the CDP and the tubepre.
I think a solid state CDP has low output imp, it isn't it?

Tyimo

ErikdeBest · 23rd January 2009, 04:53 PM

CD-players do have low output impedances, but if it is as low as 10R I don't know. Best thing is to check your manual. It is also important to terminate this transformer with at least 600R. This can be a tough load, or introduce a LP cutoff in the output coupling cap (if present) is too low in value.

Chech the driving habilities of your CD-player! I don't know if the manual shows this information, however.

Tyimo · 23rd January 2009, 06:10 PM

The manual doesn't shows this information.
I think I have to try it and I will terminate the transformer with 600R +10nF.

Greets:
Tyimo

23rd January 2009, 04:07 PM	#1
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Lundahl LL1517. What is it good for? Hi! Could somebody tell me What is the LL1517 good for? Is it possible to use in tube circuit? Something like the Raven preamp has in the input? http://www.lundahl.se/pdfs/datash/1517.pdf Tyimo

23rd January 2009, 04:15 PM	#2
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Hi The LL1517 is designed to be driven from a very low source impedance. The datasheet even mentions 'minus 18' as the optimum source. The frequency response is given when driven by a source resistance of 10 ohms, fed into 600R. Those are too low values for tubes. Ok, a white cathode follower may achieve a R out of 10 ohms and not distort to much when driving 600R, but that is about it in the 'tube world'. Erik __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

23rd January 2009, 04:53 PM	#4
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	CD-players do have low output impedances, but if it is as low as 10R I don't know. Best thing is to check your manual. It is also important to terminate this transformer with at least 600R. This can be a tough load, or introduce a LP cutoff in the output coupling cap (if present) is too low in value. Chech the driving habilities of your CD-player! I don't know if the manual shows this information, however. __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

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23rd January 2009, 04:37 PM	#3
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Hi Erik! I would connect it between the CDP and the tubepre. I think a solid state CDP has low output imp, it isn't it? Tyimo

23rd January 2009, 06:10 PM	#5
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	The manual doesn't shows this information. I think I have to try it and I will terminate the transformer with 600R +10nF. Greets: Tyimo

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