cutting a 78 on VMS at 45

Post: # 19339Unread post **Masterlabs** Mon Apr 23, 2012 12:52 pm

Hi Trolls..first real post after lurking for 5 yrs..
I have an 'Art' project job for a one off 10" 78 to be played on a standard 'Gramaphone' pic attached.I have not cut it yet, but needed some support...
1.I hope to use the one apollo (non acetate) dub I have , given to me by my distributor as a prototype.(no alu base, just looks like a reg 'vinyl 10""
2.I know this is a harder compound than my reg apollo dubs.Will i increase heat?will my saff stylus work?
3.78's have a different grove shape, I have an Ortofon OM5E stylus for transcription purpose which I use alot , but have never cut one with SX74?
4.I have detuned the dialogue to -0.5679 in my Sadie
5. I have done a dry run also.., and looks ok.
6.Why do these obscure / little money jobs , take 4x the amount of time to do..? love of vinyl, or I will not be beaten by a challenge?

Thanks

Post: # 19340Unread post **Masterlabs** Mon Apr 23, 2012 1:49 pm

Also, my Lyrec SM/8 does 78/ and lathe... But I used my ZA 33 to switch to 16.2/3 +22 1/2 for half speed cutting...wich most clients prefer ...dohhh double time for me...

Post: # 19341Unread post **opcode66** Mon Apr 23, 2012 2:05 pm

What is a ZA 33?

PS 66 Programmer Plugs are used to control motor speed, lpi conversion, delays, etc for different RPM and Diameter. Not sure I've ever heard of a ZA 33.

Of course you can alter the speed of the source material and cut at a standard speed so when played back at 78 it will sound fine. You would likely have to adjust your EQ to compensate for the RIAA EQ built into the amp rack since your audio will be pitched lower.

If you want to cut at 78 you need a PS 66 box that is 78. Or, you could convert one of your existing boxes. I can actually build these now. At least the internals. I haven't got to actually fabricating a box.

If you had a spare programmer and wanted it to be converted to 78 let me know. I can also add a selector for switching between the three diameters.

Post: # 19342Unread post **Masterlabs** Mon Apr 23, 2012 2:24 pm

Hi Opcode, A ZA 33 is the Neumann voltage change box used to halve the voltage (380v) to supply the Lyrec at the 3 x 1/2 speed...(huge caps!!) On a VMS special.
I did alter speed of source (original post -.59672)

"You would likely have to adjust your EQ to compensate for the RIAA EQ built into the amp rack since your audio will be pitched lower".
Exactly my friend , what EQ shape , and depth /stylus would you use>>?.

Post: # 19343Unread post **Masterlabs** Mon Apr 23, 2012 2:32 pm

Ps, I dont use the EQ in my amps , I use preset shapes on a GML x 2 for cutting. Flo& Ivo both bypassed/brigged the EQ in my amps.. although I would love better clearer power!!! It wont be long , building as we speek

1

Post: # 19344Unread post **markrob** Mon Apr 23, 2012 3:33 pm

Hi,

Shouldn't the detune amount be .575? (45 rpm /78.26 rpm). Also, if this is to be for a real acoustic phono playback, then I believe you will cut with no EQ if the head is flat vs. velocity. I'd cut the program material lows below 100hz-200 Hz. and the highs above 5-6 Khz. As far as groove geometry, you should be able to use a standard microgroove stylus at a larger depth. The fact that the tip has a smaller radius will not matter as long as the playback stylus can sit in the groove.

Mark

Post: # 19346Unread post **opcode66** Mon Apr 23, 2012 3:40 pm

markrob wrote:Also, if this is to be for a real acoustic phono playback, then I believe you will cut with no EQ if the head is flat vs. velocity.

Excellent point! Duh!

Post: # 19347Unread post **Masterlabs** Mon Apr 23, 2012 3:43 pm

markrob wrote:Hi,

Shouldn't the detune amount be .575? (45 rpm /78.26 rpm). Also, if this is to be for a real acoustic phono playback, then I believe you will cut with no EQ if the head is flat vs. velocity. I'd cut the program material lows below 100hz-200 Hz. and the highs above 5-6 Khz. As far as groove geometry, you should be able to use a standard microgroove stylus at a larger depth. The fact that the tip has a smaller radius will not matter as long as the playback stylus can sit in the groove.

Mark

Now this is what I was looking for...Brilliant, thanks markRob```makes alot of sense,,,

Post: # 19354Unread post **Steve E.** Tue Apr 24, 2012 5:47 am

markrob wrote:Hi,

Shouldn't the detune amount be .575? (45 rpm /78.26 rpm).

Not for Ireland, I reckon. He's in a 50 hz standard country, so the 78 rpm standard is actually 77 71/77 or 77.922077920. So the detune would be .5775.

Splitting hairs for sure!

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