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Line output transformer

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Posted on November 20, 2016 at 06:08:48
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
Dear Kevin,
Do Lundahl offer any premium standard amorphous parallel feed line output transformer with primary impedance around 3.6K:600R??

The tube is bias at 100v 30mA.

Thanks!
Regards,
PPT

 

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RE: Line output transformer, posted on November 20, 2016 at 10:19:42
drsx
Audiophile

Posts: 366
Location: around
Joined: September 11, 2005
That's a turns ratio of 2.5:1. The LL1676 will do 2:1 or 4:1. The LL1930 will do 2.9:1, but it is on nickel.

 

RE: Line output transformer, posted on November 20, 2016 at 14:50:56
KevinC
Manufacturer

Posts: 2906
Location: NC
Joined: April 19, 2001
The previous post answers your question as close to your goal as Lundahl can come.

Kevin Carter
K&K Audio
www.kandkaudio.com

 

RE: Line output transformer, posted on November 21, 2016 at 19:02:33
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
Therefore, do both Lundahl line parallel feed OPT have pri impedance closed to 3.6K or more??

Also, do they offer silver winding for both??

Thanks!

 

RE: Line output transformer, posted on November 22, 2016 at 06:28:31
KevinC
Manufacturer

Posts: 2906
Location: NC
Joined: April 19, 2001
Sorry, but no silver wire versions for either.

Either of these transformers have adequate primary inductance for parafeed use with source (plate) impedances greater than 3.6K.


Kevin Carter
K&K Audio
www.kandkaudio.com

 

RE: Line output transformer, posted on November 26, 2016 at 08:59:36
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
Does it mean the primary impedance of either model have higher than 3.6K??

 

RE: Line output transformer, posted on November 26, 2016 at 10:13:05
KevinC
Manufacturer

Posts: 2906
Location: NC
Joined: April 19, 2001
To quote the Lundahl website:

The primary impedance of a transformer in an application, as seen by the source, is the primary no load impedance in parallel with the transformed load. The "primary no load impedance" for a gapped tube amp transformer is the primary inductance. The "transformed load" is the secondary load as seen from the primary winding (Load * (turns ratio)*(turns ratio)). Thus, the transformer by itself does not have an impedance that can be used without a context.

The transformers that we have been exchanging posts about can be used with sources in the 3K-6K range, but the load reflected to the primary is a matter of the load impedance.

Historically, transformer manufacturers listed windings impedances that were in the middle of the range designed for. Lundahl does not do this.




Kevin Carter
K&K Audio
www.kandkaudio.com

 

RE: Line output transformer, posted on December 1, 2016 at 11:55:21
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
Hi Kevin!
Recently, I found primary impedance would work the best compare with 3.6K in my circuit.

Do you have anything like that from Lundahl? Again for parafeed line application.

Thanks!

 

RE: Line output transformer, posted on December 2, 2016 at 18:22:55
KevinC
Manufacturer

Posts: 2906
Location: NC
Joined: April 19, 2001
What is the load impedance for your parafeed circuit?

Kevin Carter
K&K Audio
www.kandkaudio.com

 

RE: Line output transformer, posted on December 3, 2016 at 07:01:57
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
I'm seeking 6K:600R output transformer for my parafeed line stage.

And my friend is seeking a very high quality line output transformer for his 417A (one tube per channel) for his project, whether 10K:600R adequate? Does amorphous core available for such a transformer?

Thanks again!

 

RE: Line output transformer, posted on March 10, 2017 at 07:44:05
pushpulltriode
Audiophile

Posts: 762
Joined: September 20, 2000
For 6H30, and just found out recently. 6K is the best, anything more than 3.6K is just fine.

 

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