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Old 23rd February 2014, 08:45 PM   #12121
Salas is offline Salas  Greece
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Quote:
Originally Posted by pellesmil View Post
Changed input load to 200ohm, the plan was to see if the midbass could be reduced
Went from 100ohm naked Z-foil to a 200ohm Dahle cmf55

The change was as expected , a little less midbass along with the other disadvantages you could expect going from a excellent resistor to a fairy ok resistor,

The bass peak is less prominent along with some reduced lower bass,
Not good to say how much is because of the change in value VS how much is because of the change in quality.

For those who are interested the CMF55 has some artifacts in the treble (distortion) the sound-stage is smaller and the lower bass is less detailed

Will order 150ohm and 200ohm in naked Z-foil,
You are buying load resistors in the proper load range and quality I think. Regarding your bit bumped up midbass revisit the VTF with extra care, those 33 series seem very demanding in regard to setting IMO. Not that they protest but they have significantly more to give when everything is just right. +/- 0.1g can be the answer. Their styli are apparently very precisely done, thus extra sensitive to how they sit in the groove. The MicroLine tip especially is highly accurate with minimal inner groove distortion (IGD) and it could clear 25cm/sec velocity in independent tests. Looks like its coming from Namiki Precision Jewel Co. Ltd. Japan, possibly for Lyra and Dynavector too, only they name it "Microridge". After VTF, VTA, & antiskating are thoroughly balanced, only then the loading can be really judged in synergy. The point where loading is too light (high) is usually hit when the surface noise migrates from "around the music" to "over the music". Use some complex dense cut like New Orleans Jazz, Cape Verde or Brazilian Ethnic, or classical with choral sections to fine tune for max resolution and tonal balance. The more mouths and instruments without glare you can distinct, the better. Then play Daft Punk and Sonic Youth for instance and see if the bass is overpowering or the guitars had lost healthy edge. Some Springsteen and PJ Harvey to judge weight and "air" in known voices etc. A voice from a live concert commenting or announcing something should appear dead center and have reverberation on it, emanating rather behind the plane of the speakers, background dialogues or audience cheer, chanting and whistling should be intelligible.
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Old 23rd February 2014, 09:10 PM   #12122
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I am (belatedly) about to start my project.
I will order custom transformers this week - flux drain and shielded 50VA 36V toroids. I have everything else set to go aside from a pair of 8.2-8.5 for Q4 - I do have a pair 8.11/8.05 - will these do? Alternatively if anyone has a good match pair within the range they wish to sell and ship to Australia - I would be keen.
I'm looking forward to this
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Old 23rd February 2014, 09:57 PM   #12123
Salas is offline Salas  Greece
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They will do, you may end up with 0.XdB less gain than target its the only price. Not a problem if the cart is healthy for the chosen config. Just 0.7% dif in IDSS matching won't matter significantly. What cart and gain setting are you planning?
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Old 24th February 2014, 01:54 AM   #12124
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I'm building for a 40db gain for OM2 black MM cart
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Old 24th February 2014, 02:11 AM   #12125
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Maybe 2M Black? One of the best. Plenty of output and when the gain is low the matching is making less of a difference. Also test points get stabler due to high value R2. Good luck and let us know your progress. Another good one MM in cheaper budget is AT440MLa.
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Old 24th February 2014, 03:21 AM   #12126
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Of course yes 2M Black - I've had it for a while. I've got everything done now aside from most of the resistors and the PSU. Should be able to test it out sometime over the next 2 weeks.

Quote:
Originally Posted by Salas View Post
Maybe 2M Black? One of the best. Plenty of output and when the gain is low the matching is making less of a difference. Also test points get stabler due to high value R2. Good luck and let us know your progress. Another good one MM in cheaper budget is AT440MLa.
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Old 24th February 2014, 03:51 AM   #12127
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Also a reality check - for 40db gain, and 12.5 IDSS - am I susing 91R R2 as at the bottom of the notes on gain, as opposed to the 369BL matching notes suggesting 5.1-6.8R - they seem a long way apart
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Old 24th February 2014, 04:31 AM   #12128
Salas is offline Salas  Greece
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Yes, its right. Your cart's signal level is 10-20 times more from MC or LMC too, asks for higher Vgs bias headroom to fit in (R2 Vdrop) plus your cart's motor impedance in the 1.2K renders R2's Johnson noise irrelevant as it swamps the 91R.
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Old 24th February 2014, 06:21 PM   #12129
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Quote:
Originally Posted by Salas View Post
You are buying load resistors in the proper load range and quality I think. Regarding your bit bumped up midbass revisit the VTF with extra care, those 33 series seem very demanding in regard to setting IMO. Not that they protest but they have significantly more to give when everything is just right. +/- 0.1g can be the answer. Their styli are apparently very precisely done, thus extra sensitive to how they sit in the groove. The MicroLine tip especially is highly accurate with minimal inner groove distortion (IGD) and it could clear 25cm/sec velocity in independent tests. Looks like its coming from Namiki Precision Jewel Co. Ltd. Japan, possibly for Lyra and Dynavector too, only they name it "Microridge". After VTF, VTA, & antiskating are thoroughly balanced, only then the loading can be really judged in synergy. The point where loading is too light (high) is usually hit when the surface noise migrates from "around the music" to "over the music". Use some complex dense cut like New Orleans Jazz, Cape Verde or Brazilian Ethnic, or classical with choral sections to fine tune for max resolution and tonal balance. The more mouths and instruments without glare you can distinct, the better. Then play Daft Punk and Sonic Youth for instance and see if the bass is overpowering or the guitars had lost healthy edge. Some Springsteen and PJ Harvey to judge weight and "air" in known voices etc. A voice from a live concert commenting or announcing something should appear dead center and have reverberation on it, emanating rather behind the plane of the speakers, background dialogues or audience cheer, chanting and whistling should be intelligible.

Thank you Salas, very god explanation,
i belie i run about 2,2g weight and slightly negative VTA, (tonearm lower in the bearing end)
I ll do more adjustment when the final Riaa cabinet is done
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Old 24th February 2014, 06:45 PM   #12130
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I need some advice, I see a lot of builds with Clarity Cap in place of C4, but I have Mundorf Silver, is Clarity better?

The same goes for C3, in this case I have Obbligato Gold, are there any better alternatives?
Thanks to you all.
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