Phono Transfer System Construction Information

Construction information for DIY projects, including the MS Mid Side Matrix, Elliptic Equalizer, Mastering Console, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
billshurv
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Re: Phono Transfer System Construction Information

Post by billshurv »

I would agree. Problem is that he currently has an Ifi phono and he prefers 47k on all MCs on that. Explaining the function of loading isn't helping. But I will keep working on that.
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JR.
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Re: Phono Transfer System Construction Information

Post by JR. »

Back in the day I think I terminated my MC input with 20 ohm...

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mediatechnology
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Re: Phono Transfer System Construction Information

Post by mediatechnology »

I noticed that the DL-103 QC frequency response curve had a 1KΩ load.

I have a CBS STR-112 disc with a 1 kHz square wave in a lateral-left-right-vertical sequence.
I want to try the DL-103 with 30Ω, 100Ω and 1KΩ to see if there is a discernible transient response difference.

My listening and noise tests were with a 100Ω termination which is the recommended minimum.

I have a Kenwood C2 preamp that has 10Ω, 30Ω and 100Ω.
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JR.
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Re: Phono Transfer System Construction Information

Post by JR. »

I probably don't have any more left, but i used to sell a 4 station dip switch PCB (gold plated switch contacts) for switching in and out termination capacitors to better load MM carts (24,47,100,200pF). A similar approach might work with resistors for MC (10,20,39,82 ohm). Of course why not use 1% values for esoteric fiddling. :lol:

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mediatechnology
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Re: Phono Transfer System Construction Information

Post by mediatechnology »

You sent me one of those along with the dip switch. I've got it on my bench to build up for a MM capacitor load.

I have 3 jumpers on the MC board for loading.
I was considering a 1:2:5 step of either 10, 20, 50, 1KΩ or 100, 200, 500, 1KΩ on my assembled boards.
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JR.
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Re: Phono Transfer System Construction Information

Post by JR. »

I was going for the classic 1x, 2x, 4x, 8x binary progression so you could cover up to 15x with fair resolution by mixing and matching...perhaps a little wonky for hifi market. all switches open gives you the nominal load termination.

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billshurv
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Re: Phono Transfer System Construction Information

Post by billshurv »

Last time I tried messing with MC loading I nearly went mad so personally ignore it other than setting to manufacturers recommendation. And I don't change cartridges 4 times a day like he sometimes does. I am not going to offer him a 4 way option as that's just way too much soldering for me :D
Gold
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Re: Phono Transfer System Construction Information

Post by Gold »

I've never had any luck flattening out cartridge response via termination. Most of the time the problem with cartridges sounds like a resonant peak. I've never tried to measure it. Terminating an MM cart with capacitance forms an LPF, right? How could that possibly work?
billshurv
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Re: Phono Transfer System Construction Information

Post by billshurv »

well that is one of the things I want to investigate further. There is no accurate electromechanical model of an MM cartridge out there despite many attempts over the years. Thanks to Hans I now have some accurate electrical models so can hopefully extract the mechanical performance from that.
billshurv
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Re: Phono Transfer System Construction Information

Post by billshurv »

Have clarified the spec and I don't have to handle the return from digital RIAA as that will go into another amp input, so I can use post RIAA gain on the analog path. Sweet. Boards in hand, time to order components :)
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