Group Buy Interest?

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So, I just re-tensioned the ribbon on the mic motor and will test later.

I have an ACM-3 ribbon from the first buy with a sagging ribbon. So is adjusting the ribbon something I could figure out how to do with know knowledge of electronics, or would you think I just wait for the new ribbon assemblies (assuming they are on this shipment)?

I think I'm probably going to have to do something hands on with either option, I'm just wondering which option (replacement or adjustment) is the easier for a novice at electronics. Any advice on the two options?
 
I have an ACM-3 ribbon from the first buy with a sagging ribbon. So is adjusting the ribbon something I could figure out how to do with know knowledge of electronics, or would you think I just wait for the new ribbon assemblies (assuming they are on this shipment)?

I think I'm probably going to have to do something hands on with either option, I'm just wondering which option (replacement or adjustment) is the easier for a novice at electronics. Any advice on the two options?
Except for checking the frequency of the ribbon, there's no electronics knowledge involved (I didn't check the frequency) - just steady-ish hands and good lighting.
 
So I guess the next question is how do you test the frequency? :D

This question came up today at Gearslutz.com - here's a cut and paste of my answer...

re: Ribbon tensioning - There are some good pictures and advice at Home Tracked with links to ribbon tensioning procedures at Gearslutz and TapeOp so I won't go into ribbon handling techniques here...

...but I could add the following - since most people don't have the equipment to measure ribbon resonant frequency (sweep oscillator and analog multi-meter) here is a technique that will get you in the ballpark.

As you know, our eye / brain system creates "persistence of vision" - its what makes a series of still images flashed on a screen appear to be continuous, or what makes a fluorescent light appear to be continuous and not a series of pulses. But if the frequency of a repetitive visual phenomena is slowed down enough our vision system will begin to notice oscillation. For example, fluorescent light flicker is more noticeable in countries where 50Hz AC is used instead of 60Hz AC.

So, regarding ribbon tension...

Bring the ribbon up to tension so that there is just the tiniest amount of sag in the middle when the ribbon is horizontal (say 0.5mm), Then tap the motor structure with your finger and watch for the vertical oscillation of the ribbon. You should see a rapid flutter of the ribbon, perhaps around 10Hz rate. If the ribbon is too tight, and the resonance too high, the vibration of the ribbon will exceed the ability of our vision system to follow the motion and it will just be a blur - probably around 50Hz as I note above. So the 0.5mm sag and loss of visible motion define the lower and upper limits for ribbon tension.

You could do a more accurate job by using the spectral analyzer software available in many sound recording applications. In this case, tension the ribbon as above, connect the ribbon mic to your recording system, tap the motor repeatedly, record the thumping, analyze the resonant frequency then repeat the procedure until you get a ribbon tuned to about 42Hz in the case of a Fathead or RSM-4 type mic, or 20Hz for an Apex 205 type mic.

One of the challenges with the Chinese ribbon mics of course is that there is no independent ajustment of ribbon tension separate from ribbon clamping - the exception being the earliest Nady RSM-2 and Tape Op group buy ribbons which we specified to have independent ribbon tension adjustment.
 
One of the challenges with the Chinese ribbon mics of course is that there is no independent ajustment of ribbon tension separate from ribbon clamping - the exception being the earliest Nady RSM-2 and Tape Op group buy ribbons which we specified to have independent ribbon tension adjustment.
That's the main reason I never tried to do it.
 
(6/08) ...Lastly, you guys are getting a lot of misinformation. That is why I first posted my comments. So without calling anyone anything...if you guys want to know to know the truth about this unit, I am happy to tell you. If you have questions, I will answer them as I know the entire history of the units you are getting.
Hey Alan

I was ready way back then. I still am, and maybe others are now too. If you see this, let us know. (Or if there's a link to somewhere you've already explained it, let me know.)
 
Hey Alan

I was ready way back then. I still am, and maybe others are now too. If you see this, let us know. (Or if there's a link to somewhere you've already explained it, let me know.)

FWIW, I PM'd Alan at the time he offered to tell his side. I will respect his desire to keep some of his views off the board, but I will say that his response to me didn't indicate any expectation of technical problems. There was nothing like "you'll regret buying these things because they're fraught with problems".

I have no regrets whatsoever since I still have a trifecta of NO's in shipping :(
 
Hey Alan

I was ready way back then. I still am, and maybe others are now too. If you see this, let us know. (Or if there's a link to somewhere you've already explained it, let me know.)

Perhaps a PM would be in order.....unless your intent is to light the fire on another $#!%storm.
 
moving forward.

well, still waiting for my 81s got my 84's and 1200 and 310s and love them! so far. Hopefully the 81s will be here monday or Tuesday. 6 boxes-249lbs total to Seattle, WA was $230, about 9% of the order cost.
Loving the 84's, they do break up/ sound more brittle than my Chameleons, but I do love them. With the 84s seem very quiet, aside from the "off" spot on the knob that should be off... how did they miss this? seriously!
Well, I posted concerns at the start of this about the psu being in the same case, so far it works for me but it must be a mixed bag.
I think a lot of problems would've solved if we schematics and a list of parts, it's not too much to ask for a BOM before production starts.
There's a vast resource to go over this shit and make sure it's right in the first place. I think we'd all like that.
We all jumped in not knowing what we were getting exactly, it's not Chance, we all jumped in. I'm happy, so far, but it all could be improved.
Thanks Chance! but lets review and fix shit before it ships next time!
and seriously, thanks! only trying to improve on what you started.
 
Perhaps a PM would be in order.....unless your intent is to light the fire on another $#!%storm.
I have no intent to start a shitstorm. Since these things are fraught with problems, I'd like to know their provenence, and I'll bet a lot of others would also.

I have no ill will toward chance - quite the opposite - I'm grateful for having these, and all the work he put into getting them. I'd guess he was an innocent dupe in all this, with the Chinese playing us all like a cheap fiddle.

So I think a public explanation, from different points of view, of what went down would be welcome, especially in light of the possibility of future group buys (though if I were chance this would be the end of them. :))
 
Crazy,

You're treading a fine line..............;)

So many people chose not to believe Alan back then, too many resorted to outright insulting comments, (especially regarding Alan's reasons for posting certain info), which were not only directed at Alan himself but at some of us who were aware of at least some of what he knew, that inviting him to re-enter this thread is "questionable".

FFS, someone recently took exception to me telling someone else to "watch their PMs" because I chose to answer an AH oriented question privately rather than risk adding more fuel to the smouldering fire.:rolleyes::eek:

:cool:
 
One would like to think so but unfortunately, there's too many who will take ANY opportunity to take pot shots at Alan, regardless of what he has to say.

:cool:
 
I have no ill will toward chance - quite the opposite - I'm grateful for having these, and all the work he put into getting them. I'd guess he was an innocent dupe in all this, with the Chinese playing us all like a cheap fiddle.

I can't speak for Chance, but if he's anything like me, I'm sure he'd appreciate it then if you PM'd alan directly. We've all been down the path several times and I don't think any of us particularly care to go back. Then, if there's anything you think we all should know, feel free to share.....

I for one am sick and tired of the "altruism" of a few members of this group (not yourself) who try to convince the world of the good will of other manufacturers (who shall remain nameless) towards this particular GB.
 
There was nothing like "you'll regret buying these things because they're fraught with problems".

It's safe to say that samples from any company will never have problems. It is safe to assume that any defective units would have been weeded out of any batch produced for demo purposes. Therefore, unless he had a run of them built, he probably never saw these problems.

Unfortunately, it is quickly becoming clear that the supposed delays to test every unit were complete B.S. The delays were probably because the company was busy building products for bigger clients. Then, when they got a few free cycles, they set up a line, then cranked our pres out. Because they were so late, they didn't have time for any real testing much more extensive than "plug it in and make sure it doesn't smoke", so they just tossed them into a boat and hoped for the best. Heck, some of them had wires unplugged. If those passed QA testing, my name is Elmo. That shouldn't even have passed the physical inspection stage before case assembly... before QA testing.

The failure rate we're seeing here is pretty much unprecedented. These units have a higher failure rate than I'd expect from a first round prototype production....

In any final production run at a legitimate manufacturer, 100% of units are tested, and a burn-in test failure rate of 1% in a test cycle would shut down the line. A customer failure rate of 5% would get the line shut down permanently (likely along with the manufacturer in question). Thus, a customer DOA failure rate of what appears to be on the order of 100% for an entire run (I have yet to hear reports of any completely non-humming 81s or 73s) is absolutely unheard of---absolutely unprecedented. That goes beyond criminally negligent, all the way to completely and utterly incompetent.

Based on the failure rates I'm seeing here, I can't believe ANYBODY deals with this manufacturer for anything. I wouldn't hire them to wipe my a**, much less manufacture products for me in the future.

Don't get me wrong, I don't blame Chance for any of this. We knew it could be a crapshoot. I never in my wildest dreams would have expected the level of negligence I've seen on the manufacturer's part, though. Chance, I think you should inform the manufacturer that short of them doing an entire new TESTED production run (including shipping) of the 81s and 73s for us, future rackmount hardware will be manufactured by someone else. And stick to it. You deserve better than this s**t. We all do.

If you want a good manufacturing plant (at least for building pres), get in touch with Quanta over in Taiwan. I'm pretty sure you'll get better results (assuming they'll do runs this small). They are, at least judging from their website, moving into the space of being a full-service engineering support house (doing board layout, etc.). At the very least, they'd never ship you hundreds of units without doing the slightest bit of testing....
 
In any final production run at a legitimate manufacturer, 100% of units are tested, and a burn-in test failure rate of 1% in a test cycle would shut down the line. A customer failure rate of 5% would get the line shut down permanently (likely along with the manufacturer in question).

I run about a 3% initial failure rate on testing :o but my warranty claims rate is about one-tenth of that . . .
 
I can't imagine how stressed I'd be if I had been reading all these threads and had not received my pre's yet. Fortunately (for me at least), I picked mine up right away and have been thrilled - using them all the time since plugging them in. Yes there are issues, but even with the issues, I'm still very happy as I have 6 pre's that are very different than my API's, SH, Purple and D&R's. Ones that are absolutely useable. And I believe that soon, we will have useable EQ's as well. Hang in there guys!!! It's not as bad as you think.....
 
I can't imagine how stressed I'd be if I had been reading all these threads and had not received my pre's yet. Fortunately (for me at least), I picked mine up right away and have been thrilled - using them all the time since plugging them in. Yes there are issues, but even with the issues, I'm still very happy as I have 6 pre's that are very different than my API's, SH, Purple and D&R's. Ones that are absolutely useable. And I believe that soon, we will have useable EQ's as well. Hang in there guys!!! It's not as bad as you think.....

Wow. Which model(s)? If you have 81s or 73s that don't hum at all, you may be the first to post here. :)
 
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