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Exhibition reproducer sound differences

Posted: Sun Jan 08, 2017 7:43 pm
by Markola
Hey guys, I could use your input on an issue I’ve occasionally noticed with Exhibition reproducers, which is a big difference in sound quality between repros of seemingly similar conditions.

Today I compared two Exhibitions, both which came with VV-IVs I’m currently restoring. One repro is serial #47,443A (on machine #24,682-A) and the other is #613,152N (on machine #398,490). If they’re both original to their machines, they were made during/before 1912 and 1918, respectively. So let’s call them “older” and “newer” for clarity’s sake.

They are in similar condition and both have been “semi-restored” (by the same guy) with new gaskets and back flanges, but everything else seemingly original. The sound difference between them is striking. The older one has perhaps the best sound I’ve heard from an Exhibition – full and fairly warm (not harsh or brittle) and reproduces midrange instruments like clarinet, sax, and voice in a fairly life-like manner. The other (newer) one is much quieter and quite brittle sounding, missing the warm midrange of the older one. (I tested both on the same machine, same record, same needle.)

One obvious difference is the size of the flanges (see pics). The newer one is quite a bit deeper, and the whole reproducer is thicker than the older one when compared side-by-side. (In all pics, the older is on the left and the newer is on the right.)

SO… is the sound difference primarily due to the flange difference? And can I put the flange type of the older one on the newer repro, or will it not fit? Do some manufacturers make better sounding flanges than others?

Or should I start by adjusting the tension of the flange screws (the newer ones seem tighter than the older) followed by maybe adjusting the tension of the needle bar screws, in an effort to make the newer sound like the older?

(I’m not touching the older one, btw. I love the way it sounds as is. I’m going to use it as the standard to try and bring the others up to, once I get a better handle on how to “tune” the Exhibition reproducer.)

So please, let fly with your tuning tips! And thanks in advance! :D
Mark

Re: Exhibition reproducer sound differences

Posted: Sun Jan 08, 2017 8:10 pm
by gramophone-georg
I'm going to go with the one with the thinner flange having better spring adjustment and what appears to be much cleaner pivot points. It's possible the tension springs on the worse sounding one need to be replaced, too.

Try swapping the flanges and the screws with them first to see if that fixes it or not, then you'll know for sure.

Re: Exhibition reproducer sound differences

Posted: Sun Jan 08, 2017 10:13 pm
by Remmotors
The flange should have limited affect on the sound. The gaskets, diaphragm and tension of the springs are what affect sound quality. The gaskets should be lightly shellacked to the diaphragm and the diaphragm must NOT touch the side of the reproducer body. The springs should be adjusted so the foot of the needle bar just touches the diaphragm. The foot should neither push nor pull on the diaphragm. You will be amazed how well an Exhibition reproducer can sound when properly adjusted.
Roy

Re: Exhibition reproducer sound differences

Posted: Sun Jan 08, 2017 10:51 pm
by Markola
Thanks, Georg and Roy. I'll see what I can gain by adjusting the tension on the needle bar.

So, are these two different iterations of the Exhibition, or the same version with the only difference being the flanges? (They were apparently made several years apart, so I could believe some modifications were made in the interim...)

Re: Exhibition reproducer sound differences

Posted: Sun Jan 08, 2017 11:14 pm
by wjw
Hey, Mark: I have found that another big factor in "tuning" these things is the mica. If you had several spare diaphragms you could flip them around on a hard table and note that some make a lively ring as if they were glass and others sound dead like plastic. The ringers of course sound better in use.
- bill

Re: Exhibition reproducer sound differences

Posted: Mon Jan 09, 2017 9:39 am
by Henry
Ditto remmotors and wjw comments. The mica and front gaskets are crucial, as well as the needle bar adjustment and wax seal. One observation: I did not shellac the front gaskets as per Victor instructions; I believe this step functions merely to hold them in place when assembling the other components; I don't think that it affects sound reproduction if everything else is properly done. My Exhibition serial is #859294N, and I believe it to be original to my VV-XI #370333G (1917).

Re: Exhibition reproducer sound differences

Posted: Mon Jan 09, 2017 11:30 pm
by Markola
Thanks for the replies so far - lots of good info here!

Can you buy new mica diaphragms that are the same thickness as the original ones?

(I can easily believe they make a big difference. I'm a drummer and an audio engineer, and the drumhead makes as much difference as the drum itself, and the diaphragm of a microphone - regarding thickness and tension - makes a huge difference in sound quality.)

Thanks again,
Mark

Re: Exhibition reproducer sound differences

Posted: Tue Jan 10, 2017 4:22 pm
by Remmotors
Mark,
Ron Sitko, (518) 371-8549 has good quality reproduction mica diaphragms, white tubing, rear flanges and a host of other parts available. He is a great guy and will be happy to help you out!
Roy

Re: Exhibition reproducer sound differences

Posted: Tue Jan 10, 2017 7:49 pm
by Markola
Thanks, Roy - much appreciated! :D