Comparison

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Comparison

Postby SBRunyan » Tue Jan 10, 2012 2:03 am

I am trying, with great difficulty, to make a decision between two of Mr. Leven's designs. I don't have enough experience to make a comparison myself and always enjoy hearing what others think, so I am curios to hear what others believe the relative merits of the two SE designs by Mr Leven that utilize the EML 300BXLS. The 20 watt circuit uses the 6SN7 and the 14 watt uses the 6H30 as input tubes. So what do you believe are the relative merits of these two designs ? Thank you so much. :D

14 watt using the 6H30 http://www.4tubes.com/SCHEMATICS/LUNDAHL-TRANSFORMERS/!LEVEN-Germany/300B-SE/index.htm

20 watt using the 6SN7 http://www.4tubes.com/SCHEMATICS/LUNDAHL-TRANSFORMERS/!LEVEN-Germany/300B-XLS/index.htm
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Re: Comparison

Postby SBRunyan » Fri Jan 13, 2012 7:07 pm

I am sorry, was this a stupid question?
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Re: Comparison

Postby Admin19 » Fri Jan 13, 2012 10:25 pm

The 14 Watt works on a lower plate voltage, and is a large size amplifer. So larger than a normal 300B. It can be build as Stereo Version or as Monoblock Version.

The 20 Watt works on higher plate voltage, and the power supply is larger. This is a king size amplifier, and can be only be build as mono blocks.

I think the choice comes down to this:

For a stereo Amp you can only take the 14 Watt Version. For monoblocks you can build the 14 Watt or 20 Watt version depending on the power you require.

For the rest they are individual creations, and differences in the driver stage I would mainly see as such.

Mr. Leven, please correct me if I am wrong ;)

Best regards,
Jac
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Re: Comparison

Postby SBRunyan » Sat Jan 14, 2012 12:07 am

Jac, Thanks for the reply.

Could you or Mr Leven address the tonal differences of these two amplifiers ?

What if any difference in sound does either of these 300Bxls amps have as compared to a 300B ?
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Re: Comparison

Postby J. Leven » Sat Jan 14, 2012 11:08 am

The Power at standard 300B amplifiers are 8 to 10 watts, 300Bxls 14/20 watts.
Just as important as the power tubes is the circuit layout and components of the amplifier.
A standard power supply with some 3k output transformer, 6SN7 driver and a 300B output tube is still no good SE amp.
If I have a personal evaluation noble, like stereoplay, plays the 300BXLS-SE-14 in the top class, the LE - 300BXLS-SE version 2 in the absolute top class.
The prerequisite for this is good hifi equipment, with speaker above 87 dB
J.L.
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Re: Comparison

Postby SBRunyan » Sat Jan 14, 2012 7:18 pm

Mr Leven and Jac thank you very much for taking your time to answer my questions.

Mr Leven when you say "If I have a personal evaluation noble, like stereoplay, plays the 300BXLS-SE-14 in the top class, the LE - 300BXLS-SE version 2 in the absolute top class."
Is the version 2 amplifier the schematic that uses the 6SN7 tubes or is there another version of the 300BXLS-SE-14?
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Re: Comparison

Postby J. Leven » Tue Jan 17, 2012 9:04 am

I am referring to the circuit with 6SN7 driver.
LE - 300BXLS-SE is the name of the schematic, version 2 is the index change.
A change in the circuit will also change the index, at small changes from 2.0 to 2.1,
with large changes from 2.0 to 3.0.
The index is shown below in the signature field of the schematic

J.L.
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Re: Comparison

Postby SBRunyan » Wed Jan 18, 2012 11:58 pm

Thank you so much for the clarification.
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Re: Comparison

Postby alden » Thu Oct 09, 2014 8:52 am

I think serious tube amplifiers should be used without feedback (even though the damping factor then will be poor). I however use feedback in my amps. But way lower than in the original Williamson amp. I think feedback is cheating. This is because if you choose linear tubes you do not need feedback. But the output transformer is a limiting component so some global feedback is entiteled. But choosing good OPTs (like Lundahls) you may actually design tube amps without any feedback whatsoever while they still will would sound very nice. Me, I am on the verge of designing new tube power amps. I have decided to use Lundahls OPTs and triode connected KT66's yielding one third of the price for rediculously expensive and overrated 300B's. The KT66's will be of JJ-Electronic brand.
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