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.
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mediatechnology
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Re: Phono Transfer System Construction Information

Post by mediatechnology » Wed Mar 03, 2021 9:52 am

billshurv wrote:
Tue Mar 02, 2021 6:48 pm
That is certainly the theory. But as it makes no sense from an MC perspective and they use the same cantilevers as MM there must be something else going on. Note that in the paper I quoted the mechanical resonance was frigged to give the answer they wanted but since it then drove the design of an 'inverse resonance filter' to fix the output I think the point was somewhat missed. And he didn't do any tests with vinyl and a square wave test signal it was all theoretical.
Pardon my ignorance but wouldn't the differences in mass at the end of the cantilever and the several orders of magnitude less inductance of the generator differentiate the behavior of MM from MC?

They're similar in that both sound like crap with too low a termination one being a C and the other an R.
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JP.
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Re: Phono Transfer System Construction Information

Post by JP. » Wed Mar 03, 2021 10:19 am

mediatechnology wrote:
Wed Mar 03, 2021 9:45 am
JP. Is that last image a 150 pF or 0 pF load?
The header reads 150 but the .wav file has 0 pF in the path.
I'm guessing 0.

The distortion peak is bodacious.
Similar to what I heard with the '681 lightly loaded.
150pF. The file nomenclature I used at the time was additional capacitance added.

In case it wasn't notice, the distortion is at a difference scale than the FR.

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Re: Phono Transfer System Construction Information

Post by billshurv » Wed Mar 03, 2021 10:33 am

Agree the generator behaviour is very different but the moving mass is similar, if anything lower with MM despite what some people claim so the mechanical performance should be similar UNLESS the compliance is a major contributor. Certainly something to test.

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Re: Phono Transfer System Construction Information

Post by mediatechnology » Wed Mar 03, 2021 10:34 am

JP.: The test record is the only difference?

I did notice the left and right y-axis scale differences.
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Re: Phono Transfer System Construction Information

Post by billshurv » Wed Mar 03, 2021 10:35 am

I had forgotten JP had an account here. So we have JR and JP posting next to each other and I'm already getting confused :D

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Re: Phono Transfer System Construction Information

Post by mediatechnology » Wed Mar 03, 2021 10:39 am

I'm still looking for some clarity about the difference in behavior between termination at the generator, typically by an active input and load R, and reflected termination that is connected at the secondary of a MC transformer.

One's incident the other reflected.
The reflected load has to "transverse the transformer."
My visualization of that is a click and I'm looking in the time domain.
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Re: Phono Transfer System Construction Information

Post by JP. » Wed Mar 03, 2021 10:50 am

mediatechnology wrote:
Wed Mar 03, 2021 10:34 am
JP.: The test record is the only difference?

I did notice the left and right y-axis scale differences.
Yes. TRS-1007 vs. TRS-1005.

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Re: Phono Transfer System Construction Information

Post by Gold » Tue Jun 29, 2021 9:33 am

I have three Studer A80VU Pre tape machines. I’ve never been entirely satisfied with the sound of them. After thinking about and listening to the machines for years I think the source of my discontent is the cable run from the headblock to the electronics. The reason I think that is because the aspect of the sound I dont like is an edginess I don’t hear from my A&0RC or my Telefunken M15. I thinknit is RF/EMI sneaking in during the cable run. Both of those machines have the audio electronics mounted difectly below the headblock. The Next generation Studer A820 has a preamp located below the headblock.

My solution to this would be to mount a preamp at the headblock and send a quazi line level signal to the remote electronics. Sound familiar? I was wondering if it would be possible to adapt the PTS to be a tape head playback amplifier?

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Re: Phono Transfer System Construction Information

Post by mediatechnology » Tue Jun 29, 2021 9:58 am

Paul -

Send me a scan of the A80VU preamp and I'll have a look.

Wayne
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Re: Phono Transfer System Construction Information

Post by Gold » Tue Jun 29, 2021 10:18 am

I thought the main determining factor would be the impedance of the head. I realize the EQ section doesn’t have provision for adjustable low frequency and hight frequency adjust but that can probably be worked around. The 1/4” machine uses a preamp with a step up transformer. The 1/2” and 1” use transformerless preamp.

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