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Old 1st April 2003, 03:34 PM   #11
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stigla,

This sounds like a great project.

If you try out Gary Pimm BBMCCS ,
it would be interesting to hear how you like
them after having tried normal transformer coupling.

Don't worry to much about the Miller capacitance,
build it first, and see how it works, you can allways change it later.

Good luck!
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Old 2nd April 2003, 10:14 AM   #12
stigla is offline stigla  Norway
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Slowmotion;

Thanks for your uplifitng words! I think I will try the BBMCCCS loading as well since I have all the parts for that too. I will report back when I have made some listening tests.

Hilsen

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Old 9th April 2003, 09:33 PM   #13
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hi,

I try LL1680 compare with NP-126 vintage UTC LS50 in same circuit.
Je lab pre-amp.
pls click,

http://users.starpower.net/je2a3/JELsc-TClinepre.jpg

I use 26,76.56 6j5 to test.
U will see the circuit is very simple, then the different of trans will easy to reflex to the result.

the result is np-216 is the best, ll1680 second & ls50 is worse than this two.

The most reason for the pre-amp output is the core must large than pass 15~20ma current. LL1680 only 5ma.
If use different tube had a large current. The core will easy to saturate. Then the high freq & bass will less.
certainly U can use one cap couple between the trans & tube. But If the trans was a quality one & enough current. Why not direct couple?????

Hope U will agree.

thanks

Thomas
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Old 9th April 2003, 10:07 PM   #14
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Quote:
Originally posted by siu sin man tho
hi,

I try LL1680 compare with NP-126 vintage UTC LS50 in same circuit.
Je lab pre-amp.
pls click,

http://users.starpower.net/je2a3/JELsc-TClinepre.jpg

I use 26,76.56 6j5 to test.
U will see the circuit is very simple, then the different of trans will easy to reflex to the result.

the result is np-216 is the best, ll1680 second & ls50 is worse than this two.

The most reason for the pre-amp output is the core must large than pass 15~20ma current. LL1680 only 5ma.
If use different tube had a large current. The core will easy to saturate. Then the high freq & bass will less.
certainly U can use one cap couple between the trans & tube. But If the trans was a quality one & enough current. Why not direct couple?????

Hope U will agree.

thanks

Thomas
Hi Thomas,

If you're going to do a comparison like this, at least make sure all the parts used are appropriate for the circuit. You said <i> the core must large than pass 15~20ma current. LL1680 only 5ma.</i> which means it's not a useful transformer for this application, an LL1660/18mA would have been better and then the test would have been fair. I don't have the UTC LS50 to compare specs to see where it would saturate. At best you could have tried them in parafeed, providing you kept the ratio of choke to trans inductances fairly constant or used a CCS for an anode load.
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Old 9th April 2003, 10:14 PM   #15
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brette.

I test in je lab pre amp circuit is in the same condition.
Now I hadn't LL1660/18mA on my hand, I will order one to test, later I will post the result.

thanks for your opinion.

Do U test or try the NP126 experience?
I had trial,WE, NE UTC LS50& LS151 on hand, so I can test them
in same circuit.

I still find the permalloy core pre-amp output. I know new build james had but too expensive.

thanks for your opinion.

Thomas
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Old 9th April 2003, 10:34 PM   #16
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Hey folks,
I didn't saw the "Sowther"name,when you discussed about trafo's....did you all forget it?
My recent listening test showed that,without any doubt,won any Lundahl hands down!
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Old 9th April 2003, 11:15 PM   #17
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Thomas,

I've not tried the other transformers, but that was not my point. The LL1680 allowed a lower DC bias which means one of two things
- you biassed the tubes lower, which changes how they sound, linearity, distortion etc, so it's not a direct comparison
- you saturated the core

Neither of these give a fair representation of what the trans can do. I'll be interested to hear of your results with the 1660/18

Le Bassuer,

Sowters have always intrigued me, but iron is too expensive to ship 12000 miles. Besides, I have a couple of local winders with excellent reputations I'm going to try soon. However, if you want to send me some, I'll happily try them out.
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Old 10th April 2003, 12:59 AM   #18
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Default OPTS.

Hi,

Quote:
My recent listening test showed that,without any doubt,won any Lundahl hands down!
Really?

They never had that good a rep in the past but what do I know?

Maybe economics wised up this long established British Empire company too?
It always takes them fifty years to notice a change in the world around them from their ivory towers anyway.

Cheers,
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Old 10th April 2003, 08:45 AM   #19
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Default ...OT - sorry...

Quote:
Maybe economics wised up this long established British Empire company too?
Too true Frank.

I hear the British army is going back to the Enfield Rifle - this damm modern SA80 is no good...

If you want a bullpup done right try the FN90....

cheers

James
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Old 10th April 2003, 06:40 PM   #20
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hi Brett,

if later U had time I hope U will try to consume a little bit of private time to test tango NP-126 pre-amp output.
For the cheaper product james, japan famous air tight also use their output trans.
I hope diyer had more choice.
I don't care to post one pair to U to test.
Is it very rare people in foreign area test or use tango or tamura transformers. James too.

thanks

Thomas
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