The Secret Society of Lathe Trolls

Frequency response isn't the issue, damping is. (The 68 and 74 are within 1dB to 10Hz)The reason is the cutterhead is running out of feedback control at the bottom octave. Neumann uses shelving Eq to correct for this. But when you feed in stuff an octave below this it gets unhappy. I can hear it on ...

OK... Gotta give away a neat secret here. The trick to making the 732 really work outside of an Ortofon system is to put inverse RIAA AHEAD of the side chain in the limiter. This is exactly what the 732 sees in the Ortofon system. If you feed flat program into it, it really doesn't work right. It's ...

The SX-74 has 2 drive coils, two feedback coils and a pair of heater connections. Are you just asking for the pin-out?

Hi Yann,

The RIAA encoding in the VG1 was done passively IN the power amp. There is a step up transformer, then the RIAA, then the power amp

Best,

Kev

Hi Dietrich, Zuma problems can be infuriating. John Bittner did an amazing job with development and keeping 'em running for close to 30 years, but he's DONE with them. Looking at it from his standpoint I understand. There are no more parts. As far as the Zuma 2000 I think he sold ONE and that went t...

I have a Neumann ZA 12/68B for sale. It is specifically for changing styli in the SX 68/74 heads and could be easily adapted for others. PM me.

Hi All, Just gotta jump in here. You can rewind to your hearts content but the magnets used in the 74 were higher flux than the ones in the 68. So you won't get the 74 sensitivity. That having been said a 68 is still a fine cutterhead. I have both and a 68 is a perfectly good backup. The frequency r...

Sorry for double post I got an error message that sending failed...

Hi Yann and Mossboss, I should change my middle name to RIAA... I think several points are being missed here. First, the Neumann inverse RIAA is quite accurate, certainly within a half dB from 20Hz to 20kHz. Second, on the Neumann schematics I have seen, 3 caps are paralleled for each cap to "nail" ...

I think several points are being missed here. First, the Neumann inverse RIAA is quite accurate, certainly within a half dB from 20Hz to 20kHz. Second, on the Neumann schematics I have seen, 3 caps are paralleled for each cap to "nail" the value. They were also polystyrene caps which is about as goo...

Third, St John's Wood? Abbey Road? I visited there in 1989. Very cool. Your staff gave me a very warm reception. I appreciate it! I believe your cutting rack is an SAL-74. The mod was the SAL-74B or VG-74B (The VG didn't have the tracing simulator, which nobody uses any more anyway) I too am impress...

Record Technology, RTI does most of the audiophile product plating in the US.
They also press a bunch of it.

Flo, you jumped into fast forward on the Motown story. Motown had a VMS at MoWest in Hollywood in 1972 when I worked at Artisan Sound. It was in a room about the size of a closet! No SP02 or Compudisc then...they hadn't been invented yet! It is possible that the lathe I saw was upgraded as you descr...

I use hundreds of Apollo lacquers in a year. I might get one reject in a box of 25) 14". It tends to be higher in 10" and 12" but not 20%. Are you using their "best quality" blanks? I only use masters (no drive hole). No dubs.

Hi,

It really depends on what you are using them for. I cut refs on blanks with marks. If they aren't deep you usually won't hear them. If records are made from them, the defects will show on the pressing. I don't think stylus wear is an issue unless they are gouges.

Stanly Lipshitz and Walt Jung covered all the aspects of RIAA and inverse RIAA back in the 80s. It is still the best info on the subject. ALL the guys who jumped on the "5th pole" thing got it wrong. Hagerman is one of 'em. If you read the Stereophile article sited in my first post it explains that ...

Everyone in L.A. is pretty helpful to everyone else in town when someone needs a part. I was wondering if this forum has the same spirit going on an international level. Glad to hear that is the case. I cut from CDs if that is what I'm sent, and I also use a TC22 to derive preview. I prefer to cut f...

Marcos, thanks, good to be here. I guess I qualify as a lathe troll if ever there was one! Steve has a nice thing going here. Mossboss: Glad to hear they have a lathe cranking in Australia. I got an email and some follow up pressings from a young guy cutting in Japan and he's doing some very nice so...

I hear ya. When I was still doing a lot of Rap and Dance music on vinyl I was constantly pulling out what little hair I have left! The top end would rip your ears off. Cutter current and temp were going sky high and if you filtered or HF limited the client just couldn't understand why it couldn't so...

Just reread the Positive Feedback thingy. Sorry, I misread the part about square wave response. He said 100Hz not 100kHz. My custom system cuts beautiful 1kHz square waves. I don't recall what they look like at 100Hz but the limitation would be the head. All I know is my system is ruler flat to 10Hz...