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Old 2nd December 2010, 09:38 PM   #41
RCruz is offline RCruz  Switzerland
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Sounds like Miam...
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Old 2nd December 2010, 09:43 PM   #42
Salas is offline Salas  Greece
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Better subjectively to both of us than the amorphous Lundahl we used in the first one. No one gave its nominal ratio when 47k loaded mind you. Could give about 9.5X when measured with the DVM (very high impedance) but dropped 30-40% in real use. When the naked input gave 43dB exactly as modelled when I measured it, the SUT got it up to 58dB total. It also rose THD significantly when we downloaded it at 18K. So we went to 47K as recommended in spec.
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Old 3rd December 2010, 06:45 PM   #43
Salas is offline Salas  Greece
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Further news are that the Itch also played very successfully a Sumiko Blackbird HiMC, of course without the SUT. No other changes were felt to be necessary.
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Old 3rd December 2010, 09:32 PM   #44
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by Salas View Post
Better subjectively to both of us than the amorphous Lundahl we used in the first one. No one gave its nominal ratio when 47k loaded mind you. Could give about 9.5X when measured with the DVM (very high impedance) but dropped 30-40% in real use. When the naked input gave 43dB exactly as modelled when I measured it, the SUT got it up to 58dB total. It also rose THD significantly when we downloaded it at 18K. So we went to 47K as recommended in spec.
So you mean the setup ratio is dependent of the load and amplification right ?

I am seriously considering "stepping up" my 48dB riaa with a 10x lundahl for use with a 0.15mV cart but the more I read the more I am convinced this is not an easy process.
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Old 3rd December 2010, 09:39 PM   #45
Salas is offline Salas  Greece
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I don't know, its a quirk that I did not have time to investigate enough. Maybe its individual to those tube phono matching that I had seen it. I am sure I got less than nominal ratio when in circuit in 3 cases and 2 types. Maybe its because the primary was floating, grid current, can't say as for now. There is also 1:5 and 1:20 configuration option in Lundhal.
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Old 3rd December 2010, 09:50 PM   #46
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Yes.. but it also affects reflect load to the cart.... IMO (as an unexperienced guy in this aspects) it might be quite difficult to match some carts to some TX.
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Old 3rd December 2010, 09:52 PM   #47
Salas is offline Salas  Greece
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But, wait a minute... if primary is floating and cart was surely not grounded, that is balanced transfer. The secondary sees a single ended circuit that has a signal ground. Mustn't we lose dB if it is magnetically analogous to converting from balanced to SE?
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Old 3rd December 2010, 09:56 PM   #48
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He he.... brain storming.... and you did not get hum with this configuration I guess
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Old 3rd December 2010, 10:02 PM   #49
Salas is offline Salas  Greece
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Nothing untoward with the cart and phono in the real system. Went to another system with HiMC, bypassed SUT, no problem reported from there again.
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Old 3rd December 2010, 10:03 PM   #50
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Seems like magic to me.... must try that configuration.
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