LL1630 Pre amp

DutchMark · 8th December 2006, 10:50 AM

Hi,

I have just bought some LL1630 outpu transformers for a pre-amp. I wish to use them in SE mode using E88CC. Any sugestions?

moamps · 8th December 2006, 08:30 PM

Hi:

If the transformer you have is LL1630/5mA, a good starting point may be a common cathode connection where:
+B=150V,
Ia=5-6mA,
Vg=-4-5V,
Rg=1k,
Rc=680ohm,
Cc=100uF/25V,
transformer in anode, DC coupled.

Regards,
Milan

DutchMark · 9th December 2006, 09:24 AM

Hi,

Thanks for your post. In general, would the E88CC be a good choice? Also; will the plate impedance match the LL1630?

/Mark

moamps · 10th December 2006, 11:07 AM

Hi Mark:

I think that any tube with a medium mu and Rp below 5kohm would be suitable for this type of preamplifier. You may also wish to consider tubes 5687, ECC99 and C3m (in triode). Come to think about it, I believe I even saw 6SN7 being used once to drive the transformer in an application where +B was over 300V. Mind you, I don't have any practical experience with the particular transformer you are referring to (I used1660/18mA) so please take my ramblings with a grain of salt.

Regards,
Milan

8th December 2006, 10:50 AM	#1
DutchMark diyAudio Member Join Date: Jul 2004 Location: Vught	LL1630 Pre amp Hi, I have just bought some LL1630 outpu transformers for a pre-amp. I wish to use them in SE mode using E88CC. Any sugestions?

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8th December 2006, 08:30 PM	#2
moamps diyAudio Member Join Date: Oct 2002 Location: Croatia	Hi: If the transformer you have is LL1630/5mA, a good starting point may be a common cathode connection where: +B=150V, Ia=5-6mA, Vg=-4-5V, Rg=1k, Rc=680ohm, Cc=100uF/25V, transformer in anode, DC coupled. Regards, Milan

9th December 2006, 09:24 AM	#3
DutchMark diyAudio Member Join Date: Jul 2004 Location: Vught	Hi, Thanks for your post. In general, would the E88CC be a good choice? Also; will the plate impedance match the LL1630? /Mark

10th December 2006, 11:07 AM	#4
moamps diyAudio Member Join Date: Oct 2002 Location: Croatia	Hi Mark: I think that any tube with a medium mu and Rp below 5kohm would be suitable for this type of preamplifier. You may also wish to consider tubes 5687, ECC99 and C3m (in triode). Come to think about it, I believe I even saw 6SN7 being used once to drive the transformer in an application where +B was over 300V. Mind you, I don't have any practical experience with the particular transformer you are referring to (I used1660/18mA) so please take my ramblings with a grain of salt. Regards, Milan

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