The Secret Society of Lathe Trolls

Instead of a new motor it seems it could be easier to get a different sized idler wheel to replace the 78rpm one. I'm not sure of the size you need - but if you measured the 78rpm and 45rpm idler wheels you should be able to calculate it - and then maybe get a machine shop to fabricate one for you....

I have a copy of the original documentation for the Grampian and they recommend a silicon fluid of 500 centistokes. I bought a bottle (which as little as the head takes will last a lifetime) from Spectrum. It's about the consistency of cooking oil. Two or three drops is all that's needed. Hi, Thank...

What I was trying to do was have the ending of the record loop instead of a lead out. This might be too tough for a newbie such as myself. When you master the audio, just loop the last 1.8 seconds of the audio several times. When you hit this point in the program, use the hand crank to create your ...

Hi,

I made one for myself awhile back as a DIY project and the dimensions he provided in the auction description match what I found for a 6N. They are all outside-in screws, which is what you want.

Mark

Hi Mossy, Sorry, but I think you are wrong here. The time it takes to make one revolution is what is important, not the length of the groove at a given diameter. If the loop is timed for N number of beats in 1.8 seconds (the time per rev at 33.333 RPM), then it will fit no matter where you are on th...

Hi,

I wonder how much of that rule goes back to the days when pickup tracking force was measured in oz. rather than grams?

Mark

Hi Mossy, I don't see the need to adjust loop times at inner diameters. The rotational time is the same anywhere on the disc. I took a look at how well the locked groove overlapped with an eye loop. You could see where the groove widened a bit. Possibly due to some slight movement of the head as I d...

Hi All, Just gave it a try on my 6N. I did check the platter speed with a strobe disc, but it was not off by any significant amount. No need for any loop time adjustment. So, I created a drum loop in Cubase at 133.333 bpm and printed about a minute to a wav file. Loaded it in to my computer, started...

you need a controller for the head, to move it up and down. neumann lathes have a electric controlled headmount, with a coil and spring inside. I use the famous vinylium pitch98 controller for the locked grooves. it is possible, to adjust the downtime of the head very exact. 1.8 seconds at 33RPM. I...

History of Recorded Sound is located in Culver Scully/Westrex service, Ampex service and Gotham/Grampian repair. ******** Hi Len, Welcome. I see you do work on Grampian heads. Do you have any copies for sale of tech info on the heads (e.g. manuals, service notes etc.)? Do you know what the correct ...

Hey Mark, do you have the active correct curve for the grampian? Do you calculated? Cheers Hi, I don't know if a fixed filter would work for all Grampian heads due to tolerance variations. That's where cutercollector's approach comes into play. I've used Har-Bal for this and it works well. As to le...

Yes and no. CD4 indicated that the RIAA curve to be applied would be quite different than the often published curve if the cutter head or pickup was a constant amplitude device. In the case of pickups, we talked about ceramic devices, which are constant amplitude by nature. He indicated that many of...

Hi, How are you dealing with the RIAA curve? The Gramian is flat vs. velocity, so the RIAA curve applied during reecording is the mirror of the published curve for playback with a magnetic pickup. Are you intending to aproximate this using the EQ? This might be doable by aproximation using the graph...

I'm pretty sure that the 821 cannot handle consistently loud (modern) cuts as well as an SX74. There are some fundamental problems with pushing the resonance frequency of the moving assembly of a head up that far (ie making it that lightweight) that compromise head life if used at high levels. It w...

Hi, Glad to see you got hold of a nice setup! As to your problem. It might be the positioning of the bracket that holds the motor. There are two screws that when loosened, allow you to move the motor in relation to the idler wheels. I'd guess you need to move it a bit closer on the 78 side. Also, if...

hi mossy i think that the size of the hole is the size of a universal drill tip ..iam not sure if it is the first measure of a drill bit, but hey thats just my hunch. .like a drill press and they are 100s of years old .... . Hi, As far as I can see, its smack dab in between a K (.281") and an L (.2...

Hi, Take a look at US patent numbers 2187512 2530284 and 3184242 for some of the types designed by Capps. Not sure if yours is included. Also In the Robert K. Morrison Book, "Disk Recording 1930-1960", there is a reprint of an article by Capps describing the technology. If you don't have this book, ...

Hi, Sounds like you are far along now. You need two wires to energize the coil inside the cutter head just like a speaker. The polarity is not critical. You need to determine if the coils is low or high impedance. If its low, (8-16 ohms) you can drive it with one channel of a standard modern stereo ...

Anybody--help In a dual triode tube such as the 12ax7, used to amplify both left and right channels, how is channel separation maintained? Is there some sort of partition inside the tube or is it dependent on the distance separating the two sections.? Thanx for any info. ESTG/ They are seperate sec...

No, i speak about made a "special order" iriia filter in conjuntion (phase) with the filter in the feedback loop, i believe here is the problem Ok, I understand now (sorry about being so dumb). You are looking for a for a filter to flatten the response of the Grampian head. I would leave that to so...