Post by Owen Y on Feb 1, 2019 8:53:42 GMT 12
Analog Planet (Michael Fremer) visits Manley Labs in Chino, California - with EveAnna Manley (current owner, David Manley's former wife & widow, Manley died in 2012). Manley Labs manufacture Pro Audio & HiFi products - a separate company from VTL Amplifiers, founded by David's son Luke Manley, in 1993.
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Post by cartridgeguyonline on Feb 1, 2019 16:54:15 GMT 12
Hi Owen,
Im not sure that is completely right, I thought David Manley founded VTL in the UK, in fact a few of his early models have made in UK on them. Manley was started as the professional audio side of VTL, then was split off with Luke Manley taking over the running of it, I'm assuming EveAnna got Manley as part of the divorce settlement ? There was also a Manley Zarathustra turntable which iirc was made in Spain as a tie up with an English valve amp manufacturer ? I also seem to remember reading about some amps that were made in Spain but dont remember if they were VTL or Manley ?
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Post by Owen Y on Feb 1, 2019 17:12:43 GMT 12
Yes, what you say sounds largely correct too I think, the UK origins we can recall, but I suspect that the original 'VTL' (Vacuum Tube Logic, David + Luke) is a different company from Luke's 'VTL Amplifers Inc'. The 'divorce? I have no idea. She was David's 5th wife. When he settled & later died in Spain, I believe that he was up to his 6th wife!  Some wiki is here. Stereophile's 2013 obituary to David Manley & his 'swashbuckling' life is here.
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Post by Owen Y on Feb 1, 2019 17:15:45 GMT 12
This pic (from Stereophile) tells you a bit about David Manley's lifestyle.... 
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Post by michaelw on Feb 1, 2019 18:17:39 GMT 12
i've got two editions of david manley's the vacuum tube logic book.
great reading !
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Post by Owen Y on Feb 11, 2019 20:50:19 GMT 12
That factory tour was actually rather interesting. Rather a lot of pro-audio-studio gear of course (reflecting David Manley & EveAnna's studio & guitar amp backgrounds). However some highlights: - Steelhead & Chinook phonostages in production. - New SMPS (switch mode) PSUs which will go into future Manley products (and also apparently sound better than their historic 'linear' PSU). (20:19) - Laboriously matching LDRs (Light Dependent Resistors) for a studio limiter - just like what you have to do for your LDR volume controls). (31:15) - The new $4,500 Absolute Headphone amp (with unusual narrow-vertical form factor). - Toroid transformer orientation to minimise hum (for those to say that Toroids are free from EMF radiation) - very interesting. (56:45) - Winding audio transformers in-house (I didn't know that they did that, nor did I know that they previously used Sowther TXs (which they 'reverse-engineered'!) (1:03:00) - New phono-line preamps (with SMPS) due for 2019 release. - Single-ended output sounds better than Balanced, because the latter's "complimentary' circuits replace even-order harmonics with odd-order harmonics (according to EveAnna). - Manley condenser tube mics (a la the legendary Neumann U47) - $3k each but they come packed in Pelican cases it seems!
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Post by Owen Y on Feb 12, 2019 11:38:16 GMT 12
Also interesting (at 46:17) EveAnna notes that the Jumbo Shrimp preamp (12dB linestage) has its volume control at the output end of the cct (with 'output buffer'). Many preamps (most?) have vol control at the input & (as Clarry, for example, has pointed out to me) this means that the signal is attenuated in relation to any tube/circuit noise (ie before hitting the first tube stage). One of the advantages of having the vol control at the output end, is that the incoming signal & any tube/circuit noise are attenuated together = better S/Noise ratio. (In a linestage (where the vol control usually resides), the incoming signal is normally attenuated before output to the power amp section.)
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Post by colinf on Feb 12, 2019 23:35:58 GMT 12
One can achieve low noise that way but the drive requirements of a volume control on the output of a valve line stage, and the fact that the line stage circuit is operating at full volume constantly, both conspire to make the distortion higher than it could be. Low noise and distortion can be had by using two volume controls working together: one on the input and one on the output of the line stage. A higher impedance volume control on the output of the line stage could be buffered by a unity-gain buffer to get low output impedance without increasing the noise too greatly. But having two volume controls is controversial in audiophile purist circles because then you get the sonic characteristics of two volume pots in the signal path. Audio Research had two volume controls on many of their preamps including SP-10 and SP-11, marked as Gain and Volume. Douglas Self has written quite a bit about volume controls in his book Small Signal Audio Design. A TVC on both the input and output would achieve ultimate low noise.
AMR-iFi R&D
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Post by Owen Y on Feb 13, 2019 10:34:55 GMT 12
I hadn't thought of the use of a TVC as a Line OPT. I use a TVC on the front of my linestage, with Line OPT. And, I have spare TVC. Some thought needed....
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Post by colinf on Feb 14, 2019 10:23:16 GMT 12
A TVC on the output would work just fine, as long as there isn’t any DC running through the primary. Ie. You’re not using it to bias the output valve. Are you doing that to cut the noise back?
AMR-iFi R&D
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Post by Owen Y on Feb 14, 2019 11:09:10 GMT 12
Are you doing that to cut the noise back? No, but I could have saved myself the cost of Line OPTs (However, not really as probably not as good performance as a proper Line OPT.)
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