Deep Grooves Mastering - Project Bladerunner

[Ciuens]

They are different procedures, but it is still a "professional" procedure.
I can also show Neumann procedure:^

http://www.taloowa.com/files/Download/SAL_SX%20alignment.wmv

I consider the Caruso a professional cutting head, are you?

Ciuens

[opcode66]

If you aren't measuring true disc response then it isn't a real metric.

Did you notice that Chris never measures drive directly in the video? There is a drive trimmer that is adjusted, but, not while monitoring the drive output. Watch the video and report back where the monitor selector knob is pointing in thw video while drive is adjusted please for the group.

The differences in the end result which is a cut disc could be enormous even though everything checked out by meauring drive. Once you apply to disc the stylus, everything changes. And if a system isn't perfect, negative feedback can't account for all the changes. You know that. Therefore, measuring reaponse on disc is the only honest way.

I don't own a Caruso cutterhead. I can make NO judgements of its performance.

What I can most assuredly say is that the Caruso preamp system does not include a phono preamp, and therefore could not be demonstrated in a calibration procedure such as the one I've described. Which is the only way that you can actually measure true response on disk. It would cause more customer service requests for Flo to demonstrate a process that people couldn't follow with his stock preamp. Do you understand the difference now? And why he might not demonstrated the way I am describing? I have never ever said that his cutterhead is not a professional cutterhead.

[Sillitoe]

Innovation turned to immitation, I've got the no metal blues.

[opcode66]

Show me the modular design in
Neumann??? Not there. Innovation...

Show me the neodymiums?? Not there. Innovation.

Of course I want to emluate the things Neumann was doing right.... Wouldn't you? Like properly measuring response on disc.

I could go on with the innovations found in my work, but, that suffices.

[opcode66]

Here are the official Neumann calibration instructions so there is no room for misjudgement.

Page 4 - Explanation of procedure starts

Page 6 - Calibration of heat sensing AC Bridge Circuit for tripping the electronic circuit breaker called a SEL. You calibrate the temperature here.

Page 7 - Pickup calibration via the timmers in the phono preamp and a NAB disc. RIAA is turned off for this procedure.

Page 7 - Beginning calibration procedure. Feedback Amount is adjusted while monitoring feedback and a drop of 9d is dialed in. Not while cutting. But, also not while monitoring drive... 5K tone is used at 0VU (no iRIAA) that gets dropped to -9.

Page 8 - The calibration process continues. Now we monitor PU and adjust Drive Level and Feedback Monitor Level while cutting 1K tone at 0 VU. Once you read 0VU adjust drive while monitoring PU, then you adjust 0 VU for feedback monitoring. RIAA is turned on for these procedures.

Now the system is completely calibrated. Not once was drive every monitored or measured. Cutting is absolutely a required part of the procedure to calibrate Drive Level, Feedback Amount and Feedback Monitor Level (which are the three trimmers on a Caruso board). A NAB tone disc is also required as well as a calibrated VU Meter. A multimeter and a function generator can be used to check the VU meteres 0 VU = 1.228 VAC with 1K Sine Wave. The same function generator can be used as a sound source for generating the 5K and 1K tones required for calibration.

All professional cutters I know who own a Neumann system follow this calibration process to prepare for cutting master lacquers on their system. The final measurements and checks of the system performing with feedback applied are done so while cutting and monitoring feedback. The drop is 9db. And, this will likely be the exact same procedure for calibrating Mantra. If everything was performed correctly you'll be cutting to spec and have flat response.

Pages 9-10 are a distinct bonus since they explain the math that is performed in the BSB's.

[markrob]

Hi Todd,

Got it. You are right, in the groove is the final arbiter of performance. Second best would be at the feedback monitor as this should be close to what is cut. Measuring at the drive level is not the best place, but is easy and gets you in the ballpark.

In the case of the instructions you posted, going for 9 db drop at 5K makes sense as you would not expect to attain as much feedback as you would at the system resonance (more like 20-30 db there). They elected to pick a cal point well outside of the resonance and far from the point that feedback becomes 0 as a nice repeatable reference to avoid any variations caused by the damping at the resonance. They also know know that the head exhibits well controlled open loop gain and phase response in this region.

So, given that, how much feedback are you able to apply and by what measurement method? I ask that because from the rips, it does not appear that you are able to apply enough feedback to flatten the head response. You are able to kill a good amount of the peak at your system resonance. In this case there is benefit to the feedback, but the head will still require major amounts of EQ externally to flatten.

This all may be moot if you are saying that you will not be offering this head for sale in its present form. If that's the case, then its not worth spending much time on characterizing its performance.

Mark

[flozki]

i try to stop post here. and i try to make it as a one shot.
just because its always refered to "ask flo.." or because caruso comes into the talk.
i dont want to be part of this discussion. so please leave me out in future.

good things seem to come from west coast and we can not cope with that.
( think pink and it seems there is now even free coke in l.a.)

i am baking small breads and i can not rule the cutting world. everything is slow here.
we watch the snow hills from far and take all the time we need to build the swiss made crap.
so no chance to jump on the innovation train.


all i have to say about caruso , how to setup you can read on
http://www.vinylike.com
i update from time to time and i try to make the support better every time i get some customers feedback.
and i do email or bilateral support for customers.

and all pro users please check
http://www.flokason.ch

please once again:
caruso is a cheap non professional system made out of ordinary unsexy aluminum
and should not be compared to "think pink" or other professional products.
it has its particular sound which you can hear and compare. make your own judgement. some like it some like it not.
but most of the time there is a standard 5cm/s tone and there is also an originial unprocessed file with information about playback system etc.etc.
do the same with a neumann. a westrex and whatever. so feel free to post your cutting results.
i love to hear what people do with it. but always do it this way otherwise it does not make sense and it does not help to
make the product better.

now
what i read here about alignment is just totally different to what i knew so i tell you my old boring stories how it is done by old skool people like me.
last time i promise!

all feedback driven systems have a main resonance frequency.
so search that frequency (for a brand new neumann head it was 1k. for caruso its around 1.1-1.2k at current version) and from there apply feedback.
check the point where it starts oscillation. then leave a safety margin (typ. 3 dbs) and you are safe. thats the way to do from a point of closed loop theory.

if you read westrex alignment manual thats how it is done.
if you read caruso alignment manual thats how it is done.

if you read neumann then its different , for good reason.

the 5k the minus 9dB point is chosen by neumann for safety reason. they did not wanted to play people with a 550W system in the heads main resonance!
so they did their measurements and checked how much this is on a frequency not too close to the resonance.
thats where the 5k come from. this is a virtual value. well chosen but has nothing to do with the regulation loop.
a good stable head and system will be >14 dBs. if you reach 15 perfect. the best and last state of the art vinylium repairs with ceramic feedback coils reached around17-18 dbs
that was the top of the top i have ever seen.
important is to know the 9dBs and thats what you have to set on that system

but this was done for neumann. with their particular amps system and does not give a comparable value for other heads, amp systems. even on most worn out Sx74 it
is not really the case anymore....but we can live with it.

so they only real way to know about stability is the test with main resonnace and see how far ou can go from there.
1. you need a open loop plot.
2. then you close the loop and apply feedback at the main res. frequency. until you reach point of oscillation.

on westrex it was typ. 29-31dBs.
on Caruso i can go to 42 with a particular amp. on qsc amp it is only 32 or so. so all the amp , preamp is part of the system
if i use caruso on neumann SAL system i reach also something like 29-32 dBs.
all the ingredients define the soup.
(if you use the caruso pcb you have to figure out all the values yourself. i just communicate values that work for me.
absolutely no warranty if that works.)

this max number is the interesting figure. nothing else.

then alignment is in a first instance always done on FBmonitor. this works well.
check with playback system is the ultimate and best test...
but i dont know too many people who can perform that with same accuracy as with the feedback monitor. at least up to 15-16k its possible to see if the head is linear
even with a neumann head.


a linear needle is needed. (neumann standard was shure V15 which is hard to get .discussion about jelco replacement quality are ongoing and not clear answer)
a nice preamp is needed. sorry if you dont get one with the cheap caruso board...
a perfect aligned tonearm is needed.
a perfect test tone disc is needed. which is at this moment is not available in a decent quality. jvc TRS-1007 is the one you need.
if someone has mint condition i will buy at least 100 pcs.
unless you dont see a perfect flat sweep from your TRS.1007 forget about this method.
or just align it by comparing .trust your ear. sometimes much better results.

so far to the playback method.

the much simpler would be cutting test tones and look over the record with a torch in 45 degree. if bands are all in parallel you won.
this nice and parallel pattern is also a quite rare appearance. but thats something that works.

pink noise adjustment is ok if you want to do the last bit of fine tuning. but does not tell about the system stability. so do that only when the FB is aligned properly.
fab filter can help but its a matter of personal taste.

ok over and out
as the french say: "Ça Plane Pour Moi"
thats how it works for me and a few others ..


maybe a good test record ?
Plastic Bertrand
"Ça Plane Pour Moi"

[opcode66]

Thanks for confirming my points. Much appreciated. As to the rest, I already knew. But, glad that you finally disillusioned everyone. Caruso is mid grade. And you are just one guy doing stuff, not The Vinyl God. And, overall, you would rather not deal with people. So, it is good for everyone here to understand those points.

I am mostly saying "ask Flo" to people who are your customers. They should be able to ask you questions sir. I will continue to point people to you for answers about your products.

( think pink and it seems there is now even free coke in l.a.)

Exactly what are you insinuating??? I would like this explained.

Don't worry about a thing jelly been! All will be worked out in the final head for sale. My response will only improve dramatically from here. Did someone come along and pass judgements on Caruso while still in development? Did you even document the development? No. So, for anyone to say that my feedback isn't quite closing the loop yet would be making a very premature judgement seeing as though I've performed about 5 feedback cutting tests so far.

So, chill everybody. Don't worry about it. Things are coming along exactly as they should be.

It sounds to me more like someone is worried that I've come too far too quick.

A quick search of the forum for "9db" will result in a number of posts from Flo wherein all he talks about is 5Kz and 9db of feedback. Just fyi folks. A few references of 22db at 1K. But, most of the talk revolves around the Neumann spec of 5K and 9db for calibration. Which is the one I will be following. Cheers!!

[opcode66]

So, given that, how much feedback are you able to apply and by what measurement method? I ask that because from the rips, it does not appear that you are able to apply enough feedback to flatten the head response. You are able to kill a good amount of the peak at your system resonance. In this case there is benefit to the feedback, but the head will still require major amounts of EQ externally to flatten.

Way too early to make that sort of sweeping conclusion. I feel that way for two reasons. First, I have no metal. Metal will affect the response. It will affect the feedback. Everything....

Second, I have yet to tweak the components on the Caruso board to match my cutterhead. The drive coils and feedback coils are not the same as Caruso. I built my boards about a year ago following the Caruso Preamp V 1.23 schematic and I selected values for Caruso. I have been running all tests with values for Caruso. If we are going to be fair, we need to wait for me to select proper values and replace them on my test boards.

If you look at the schematic, there are many places where the values selected would have a difference on the amount and quality of feedback. R606, C401, R405, and R410 specifically. I haven't tweaked any of those values. Compounded by the fact that my impedance on my feedback coil is twice that of what it was for Caruso when the 1.23 schematic was made. With no tweak to R606 FB-GAIN having been made, this certainly accounts for less fb available to be applied than expected. It doesn't point to a problem in the physical design necessarily. It is simply that I haven't created a proper environment for testing yet. I will get there. And, results will continue to improve. Without all the details from my end, it might be easy to form the wrong conclusions. I'm trying to document as fully as possible and as time allows for me. Please be patient. And, stick with it. I'll get thing performing much better soon.

Things improved markedly and noticeably with feedback for me. Without even applying "proper" feedback. So, just imagine what corrected boards and metal are going to do for my overall performance, Markrob!

When I put the name Mantra on my video instead of Bladrunner x.x.xx then let's start truly benchmarking it. Coolio? I am still in development. And this is not my only project. I do lots of other stuff as I'm sure most people here do. But, all results indicate that I am on the correct path, moving along as expected, and when all the stars are properly aligned, this will be a hell of a head.

[opcode66]

I plan to purchase a precision Mini Metal Lathe first and get rolling with that. Start making things like the push rod/bobbins and torque tubes. The springs I will have made for me. They will be punched from spring steel likely. Other parts will be made with the assistance of a CNC to come later.

So, I would love some input from Trolls with metal knowledge. For a Precision Mini Metal Lathe I am considering the following:

http://www.ebay.com/itm/361428875298?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

s-l500.jpg

OR

http://www.ebay.com/itm/Bolton-Tools-9-x-19-Metal-Lathe-Machine-BT0919-/381241424019?hash=item58c3c27893:g:WasAAOSwKIpWBGLS

bolton.jpg

OR

http://www.ebay.com/itm/7x14-Precision-Mini-Metal-Lathe-infinite-variable-speed-2500RPM-550W-DC-motor/390734932029

20.jpg

I like the Bolton but I'm not sure I need 9" x 19" for these parts. The first one seems pretty good to me. Thoughts???

[Bahndahn]

First one is the best bang. The middle one is immense overkill.

The digital RPM on the first one is the selling feature.

Contrary to what the auxiliary photos tell you: NEVER LEAVE THE CHUCK KEY IN THE CHUCK!

[Bahndahn]

Also, don't forget to pick up:

a couple axis' worth of magnetic-base dials:

Screen Shot 2015-12-04 at 12.36.49 AM.png

a bore gauge with tips:

Screen Shot 2015-12-04 at 12.37.45 AM.png

some outside micrometers:

Screen Shot 2015-12-04 at 12.38.23 AM.png

some inside micrometers:

Screen Shot 2015-12-04 at 12.46.16 AM.png

Continues on next post..

[opcode66]

Sort of what I was thinking. On both counts. The first one. And, don't leave the key in.... You made me laugh!

I have a dial bore gauge and an outside micrometer already.

So, I'm thinking that one, combined with something like a bolton stand.

stand-B250-600x600.jpg

I also want to get a watchmakers lathe to do fine detailed work as well. Something like this

http://www.ebay.com/itm/Boley-Watchmakers-lathe-for-precision-work-Outfit-in-original-wood-box-/262170221895?hash=item3d0a901d47:g:nlwAAOSwniRWN-gT

s-l1600.jpg

[Bahndahn]

a thread gauge:

Screen Shot 2015-12-04 at 12.39.00 AM.png

some HSS blanks for the required small tooling:

Screen Shot 2015-12-04 at 12.43.22 AM.png

grinder for said tooling:

Screen Shot 2015-12-04 at 12.36.25 AM.png

and, of course, a copy of machinery's handbook:

Screen Shot 2015-12-04 at 12.41.41 AM.png

My mechanical/aerospace engineer mentor always reminds me: "your machining is only as precise as you can measure it"

The watchmaker's lathe is superfluous if you have the right mini-lathe. They, for some reason, are highly fetishized and therefore expensive. All of the money towards a the watchmaker is better spent on collet sets, index wheels, magnification equiptment, and tooling for the mini-lathe as it is going to be more rigid and capable.

[opcode66]

good things seem to come from west coast and we can not cope with that.
( think pink and it seems there is now even free coke in l.a.)

This must be what you are talking about, right?

Free-Coke.jpg

maybe a good test record ?
Plastic Bertrand
"Ça Plane Pour Moi"

I have something even better picked out! Inspired by you, sir.

[rsimms3]

I've been looking to get a small hobby lathe over the past 6 months or so. From the little bit I have read you'll want to find as much information on the lathe you choose to ensure it has real precision and not just precision in the name. I looked at the first listing, but not the second two, for specs on tolerances and such and didn't see any. A lot of those mini lathes use plastic gears and can be sloppy. Some of them are not strong enough to cut steel over and over again before something goes wrong. Not saying the ones you listed are, just do your research after you pick and before you buy. A lot of those mini-lathes are just rebadged so you might get the same thing at Harbor Freight for a cheaper price with their 20% off coupon.

[Snug Music]

Hey Todd, I .. just see that both boards operate at your Caruso-PreAmp via a single power supply! Is that right? Presented as from a single power supply?
Or was it just for testing?
By the way ... Thanks, I got the two Boards of Flo !!

Greeting Scotty

[Snug Music]

Oh Todd,..
, and .. what's still missing, would be a model building CNC milling machine. Without this machine, I would not have come this far with my project to build the head.

Otherwise you are destined for 1 week on grinding ... smile

Scotty

[opcode66]

One power supply for both boards.

I'm going to get the metal lathe acquired and setuo first. Then, immediately after, I will get the cnc. That has been the plan.

Can you tell me the make/model you are using? Do you like it?

[Bahndahn]

I hope I'm preaching to the choir here in the best way possible, and with that assumption in hand I will keep thinking aloud:

Indeed, it is likely a good idea to get a lathe first, but it is equally rivalled with the CNC. Heres why:

Lathe pros:
-Great for cylindrical work with precision
-Particularly powerful for custom threads - this is debatably its main advantage.

Lathe cons:
-LOTS of tooling, measurement, and ancillary equiptment required for even basic work.
-Limited to cylindrical work or 'facing' other shapes in a four-jaw chuck [another expensive accessory]
-drilling precise holes anywhere other than the center of the object requires an expensive accessory such as a milling attachment or a a 4-jaw.
-precision repeatability depends on YOUR technique, patience, and ability.
-setup for each new tool takes a while, depending on your post and measurement setup..

CNC pros:
-All shapes can be obtained within the constraints of your axes setup
-precision is as repeatable as your machine is precise
-less tooling required
-it is automatic! you won't spend hours trying to get it right [after you've set it up properly]

CNC cons:
-more than 3 axes is expensive
-jumping into automated machining doesn't teach you all of the fundamentals of machining
-etc.

Worth considering- the lathe is a slow, manual road.