Lundahl LL1663 PP

[K.A.B]

What to do with LL1663 PP 5K push-pull i have no idea at all.

Anders

 

[schiirrn]

Do you have them sitting around and need a project or do you abou what it was designed for?

 

[Steve Morley]

An EL34 amp springs to mind. 30 to 35 WPC. Hopefully you have a pair.

Steve

 

[mctavish]

Youu could free yourself of thee burden of this question if you choose to sell them to me..... I have been looking for a pair of these...

 

[K.A.B]

Yes i need another project even if i have a few waiting i have EL34 project in next round of building i will try them and i have a pair. No they are not fore sale.

Anders

 

[Steve Morley]

If you can't make an amp that sounds good with the Lundahls it's probably not the fault of the OPTs. I heard a set of Lundies that made a huge difference in an Elekit amp (versus the stock OPTs).

S.

 

[gingertube]

How about:
EL34 Baby Huey Amplifier
There is a group buy for PCBs to suit.
Use EL34, 6CA7 or KT77 or even 6L6.
The 33% UL taps may suit 6L6 better than the more usual 43%.
Cheers,
Ian

 

[6A3sUMMER]

UL taps: 33% will give the tube more effective transconductance (voltage to current gain) versus 43%. One disadvantage is that 33% will give the tube a higher effective plate resistance (versus 43%), so you will require more global negative feedback to get the same damping factor as the 43% tap would get.

But 33% will give more maximum watts out for the same B+ and same control grid bias than 43%.

The 6L6 is the lower transconductance of the tubes in post #7.

You should end up with a good performing and sounding amp, no matter which of those tubes you use.

 

[K.A.B]

Steve Morley@
I already have an SE amplifier with LL transformer and can agree that it can be very good but then the rest should also be good.

gingertube@

I have already assembled most of the components for an EL 34 amplifier, which is a well-known Swedish construction that several DIY builders collaborated with, but it is time for me to build mine. this amp can use whole range from 6L6 to KT88 maybe even the newer kt-tubes.

6A3sUMMER@

Thanks for remember me.

 

[Tubelab_com]

My LL1663's are in a pentode mode push pull amp with 6GF5 small TV sweep tubes. I chose the tubes and transformers because of their low height since the amp is a 2 RU rack mount case. The sound quality is very good. Power output is about 35 WPC.

 

[6A3sUMMER]

Tubelab_com,

Thanks for reminding me of Rack (height) Units, or maybe not.
With many jobs, the US Navy, Feds, and a major T&M company,
I had to work with 19 Inch Racks. Arrrgggg!

But I like your creativity to get tubes doing 35WPC into 2 RU!

 

[K.A.B]

Thank for the answers I have received I may continue to look but i have heard that EL86 may be a candidate but may research more. Of course I will try them on my upcoming EL34 build.

Anders

 

[45]

Yes, it's quite good. Basically same as EL84 with lower anode voltage. You get 18W with just 250V voltage supply (i.e. about 235V anode voltage + 15.5V self bias). Compact and economical.

 

[hpeter]

maybe time to try schade feedbacked pentodes...
should be better than UL