Always read your manual

[poppachubby]

Hey you guys. I thought I had reached the audio apex, boy was I wrong.

A fellow member of the Yahoo Bozak group sent me a copy of the original manual for the 919 preamp. Apparently, I was not using it "correctly".

I had the main volume slider at 7/8, and was using the phono slider to tweak, usually between 3 and 7. The manual says put the phono slider at 10, and use the main volume to tweak.

HOLY CHIT!!!

Basically, everything just enhanced. The most noticable improvement is that low level detail is up in my face now. The dynamic range is scary good, from quiet to loud within two notes. Absolutely gorgeous sound.

I was enjoying good, now thiings are great...almost undescribable. It's just perfect, and I still have yet to upgrade my tonearm and cart!!!

Anyhow just a thought that it's always worth it to see what the manufacturer and designer had in mind for your gear...you just may be rewarded.

The Bozak 919 was indeed an audio statement. God bless Rudy Bozak and Bob Betts!!!

[kelsci]

I had to do a search on google images to see what this pre-amp looked like and found a few pics of it with your name attached. I remember many years back that Bozak was a very respected name. My brother had a friend, long passed away, who knew Mr. Bozak. As far as a pre-amp goes, this 919 is really a nifty piece and looks very professional in its build. I would not doubt the sound quality would be first rate from such a piece.

[poppachubby]

I am quite certain that I have displayed the most images of the 919 in all of cyberspace. I made a point of doing so.

The 919 contains the same circuitry that their professional mixers had. The phono stage is the same as the legendary CMLabs CMA 10-2DL. That unit still fetches $1000 if you can believe it.

I spoke back and forth at length with Mr Betts who posts regularily at the Bozak group. The 919 was designed by Rudy Bozak and him, plus some help from a Studer/Revox engineer.

I thought it was the cat's meow, but now...I am wondering at what price point I would have to spend to unseat it. I have not stopped spinning since 7am, my wife is beginning to get upset.

Here's an interesting read if you are interested in Bozak history. BTW, members of the Bozak family post at the Bozak group also.

http://www.bobsamerica.com/bozak.html

[E-Stat]

... and was using the phono slider to tweak, usually between 3 and 7.
It is the nature of all attenuators that they perform best in their upper range. I would bypass the phono one altogether.

rw

[poppachubby]

It is the nature of all attenuators that they perform best in their upper range. I would bypass the phono one altogether.

rw

Not sure how I would do that Ralph. Having the phono slider all the way up to 10, maximizes the SNR of the 919. It truly sounds glorious, I am enjoying my vinyl in a whole new way. The best part is I am satisfied with my system, and am having alot of fun while listening.

This little revelation combined with my "new" 3A speakers has allowed for the most transparency I have ever experienced. My headphones and speakers are delivering the same info. This is a first for me.

I put the 919's specs against alot of esoteric external phono stages, and it holds up quite well. The RIAA curve is more accurate than most and the SNR is impressive in comparison.

[thekid]

Glad to hear about your "upgrade".

I usually try to download the manual to everything I pickup. It is always good to give the manual the once over before hooking stuff up. With some gear what seems to be intuitve is not really the best settings.

The one time I did'nt read the manual I screwed up what was most likely a perfectly functioning Nak RX-202. What I thought was a jammed door turned out to be a holding screw that secures the tape door mechanism during shipping. Removed the screw and the door opened up fine. Only problem was my attempt to "fix" the jammed door screwed up the timing of the auto-reverse function.

[luvtolisten]

Good point Chubbs &Kid, were are all a little guilty of bypassing the manual in the excitement using of new to us gear. I'm finally getting around to hooking up my Adcom GFP 555 & GFA 535 this weekend. Guess I had better download the manuals first.

[poppachubby]

Thanks for the replies fellas. Manuals are in short supply for the 919. The seller did not supply me with one.

When Bozak released this unit, all buyers got was a temporary manual. Apparently they mistimed the printing of the proper manual that they had intended. This temporary version is what's to be found when searching for one on Ebay or the usual avenues.

Wonderful Judy Ingels sent me a copy of the full version manual, which is really special.

Yes L2L, have a looksy at your guides. At the very least you may get some useful tidbit for running those fantastic machines of yours.

[E-Stat]

Not sure how I would do that.
Wire a jumper around it if you've worked with electronics before. I built a couple of Dynakits when I was a teenager and have subsequently performed some simple mods like that on other stuff. Using a potentiometer with a low level stage like that is not a common practice.

rw

[poppachubby]

Wire a jumper around it if you've worked with electronics before. I built a couple of Dynakits when I was a teenager and have subsequently performed some simple mods like that on other stuff. Using a potentiometer with a low level stage like that is not a common practice.

rw

It's a slider. So essentially you're saying wire it so it's wide open, and direct. I could I suppose...I'll have to look at the schematic.


This is how Bozak and CM Labs made their control units. It's actually a "professional" feature. While I am listening to a line source through the speakers, I can use my headphones through the "cueing" output.

Through cueing, while a CD is playing, I can turn up the Phono while playing an LP and it will come only through the headphones. They also had this in mind for someone who may want to listen to one thing, while taping another. Further still, I can send the phono signal to another amp altogether, using the dual RCA outputs on the rear. Heady stuff...

[pixelthis]

It's a slider. So essentially you're saying wire it so it's wide open, and direct. I could I suppose...I'll have to look at the schematic.


This is how Bozak and CM Labs made their control units. It's actually a "professional" feature. While I am listening to a line source through the speakers, I can use my headphones through the "cueing" output.

Through cueing, while a CD is playing, I can turn up the Phono while playing an LP and it will come only through the headphones. They also had this in mind for someone who may want to listen to one thing, while taping another. Further still, I can send the phono signal to another amp altogether, using the dual RCA outputs on the rear. Heady stuff...

Wire it so that it will bypass the slider.
THE REASON the manual says to set it at ten is to fix a problem, mainly a slider on a phono preamp, a lot easier than just removing it in production.
I guess I can see a rare instance where you would need such a thing instead of setting output at the factory, but its only going to confuse most people.
Which is why you rarely see them.:1:

[pixelthis]

And you wire a bypass to get it out of the signal path, all it can do is screw up the output:1:

[E-Stat]

IIt's actually a "professional" feature. While I am listening to a line source through the speakers, I can use my headphones through the "cueing" output.
If you value that feature over sound quality, then by all means don't attempt to bypass it.

rw

[Geoffcin]

Using a potentiometer with a low level stage like that is not a common practice.
rw

Exactly! And the reason is that with these very low level signals they are much more sensitive to the quality of the connection, and the quality of connector/attenuator.

My guess is that at the 10 setting the attenuator is effectively bypassed, but you still have the signal going through it's contacts. If the slider is clean then you might have little or no signal loss, but the slightest corrosion and you've effectively have an unwanted filter on your phono signal.

[poppachubby]

Well of course it's clean, that was the first thing I did. At 10 the signal to noise ratio is being maximized. Obviously the features are a little far reaching for my purposes, and most folks I would say. I'll have to look inside to see what's involved.