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Author Topic: Happy Holidays to all  (Read 8106 times)

Offline stellavox

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Happy Holidays to all
« on: December 19, 2008, 06:43:25 AM »
This is going to be a rambling missive with (I guess) two purposes; one to inform folks what I?ve been doing since the beginning of the summer, the other to reinforce my opinion about what I refer to as the ?ultimate? audio accessory-  an equalizer.

Let?s start with the recent past:  I had a GREAT time at VSAC 2008 - was also disappointed by the low attendance and the lack of what I will call a ?DIY turnout?. It seemed like everyone was there to sell something. I?d opine that the DIY wave may have crested with VSAC 2003.  Enjoyed seeing the Bottlehead and Tape Project entourage along with a few of you Project participants.

In the tape deck world - Had an opportunity to finish up my ASC 6002 deck (at the moment I can?t find or don?t have a picture of it all back together again):



The 6000 is a direct descendant of the Braun TG1000 (a VERY NICE sounding machine) and was one of a few neat HiFi products produced by a group of personnel who left to form Audio System Componeten in the late ?70?s when Braun decided to discontinue that consumer product line.  Whereas the 1000 could only go to 7 1/2ips and hold a max 8 ?? reel (some kind of European standard), the 6000 could play 15 ips and hold a 10 ?? reel.  It has very nice tape handling; what I?ll call ?quasi ? constant tension? via the use of a mechanical/electronic feedback mechanism ? if you look closely, you can see that the outer tape idlers are mounted on swing arms which are coupled to a photo-optical assembly.  This then produces a variable DC component which when when added to the AC feed to the Papst reel motors varies their speed proportional to tension (pressure on the rollers).  The heavy, machined capstan assembly is belt driven from a DC motor with speed feedback via an integral tachometer.  The 6000, while "common" in Europe was never imported into the US and this must be one of a very few here ? a friend actually carried it over from Germany on a trip.  It did require a little work (shorted electrolytics) and tweaking of the playback EQ but was worth it as its audio quality is exceptional ? due in large part to the Bogen heads.  Next related project is to modify my Tandberg infrared remote control to operate it.

Current tape machine fav is the Lyrec Frieda  (never heard of it ? too bad - neither did I till a few years back ? veerrry rare) which blows away most other decks I?ve heard and nudges the Stella.

Over the summer a friend stumbled across the remaining inventory of Cello Inc. in a Bridgeport, CT warehouse.  I?m not going to bore you with a long story of that (currently) defunct brand, beyond saying that they produced some of the world?s most highly respected audio components.  Chief among them was the Audio Palette, a six-band equalizer and sibling, the Palette Preamplifier. 

Among the discovered parts were a set of populated printed circuit boards for the Preamplifier along with enough documentation to allow me to get it going.  There was no cabinetry, so I proceeded to have the sheet metal and front panels fabricated to my own specifications.  The front panel engravings are identical to the original with the exception that no mention of ?Cello? appears, to keep away from any potential copyright problems (and Front Panel Express wouldn?t reproduce it anyway without written permission from the trademark owner).

What I did differently from the original product was to separate the equalizer portion of the Palette from the preamplifier section and fabricated a 10 meter umbilical cable to connect both units.  This allows the equalizer to be placed right at my listening position to make adjustments in ?real time? without moving from my seat. The controls on the equalizer are identical in function to the original and it is mounted on an original accessory Lucite stand with 4 casters (wheels) on the bottom so it can be easily moved.



The (separate) preamplifier has 5 inputs with the other level and balance controls identical to the original Preamplifier, with one exception.  In the original Audio Palette, the ?Equalizer In-Out? switch offered the ability to reverse the absolute phase of the outputs (180 degrees) whether the equalizer is in or out of the circuit.  This feature was eliminated on the Palette Preamplifier but I added back to this version. The preamplifier is also self-powered (the original Preamplifier required a separate power supply) and supplies power to the equalizer over the umbilical cable.
 


Now in previous posts I?ve extolled the virtues of having some kind of frequency contouring ability in your HiFi system.  With a tape deck, high frequency adjustment can be easily? accomplished by making the ?R? in the high-frequency equalization network variable (and accessible).  An equalizer adds even more capability to all sources BUT I?d opine that the problem with most all equalizers (and the reason that they have been categorically trashed) is that they introduce a sound of their own.  The Palette seems to be about as neutral as it gets ? aided by the fact that the equalizer section can be bypassed via a front panel switch on the preamp. I've used it mostly in a "subtractive" mode to help take the edge from female vocalists on a few CD - actually allows me to listen through the program rather than having to eject after 2 songs.  Next plan to go back through my tape collection and probably use it in an "additive" mode - mid bass and the like.   

Finally, a few words about my current system ? speakers are Quad 63?s driven by a tweaked Lazarus Class A hybrid 50 watt amplifier.  Homebrew, center channel, Quad woofer with self contained combiner / amplifier / 4th order low pass filter from 100 hz down.  System goes down into the 20?s.  CD is a Norh CD-1 and Tape includes the Stellavox; (borrowed) Lyrec; ASC and a MCI JH110 deck with modified electronics.  FM is a SUMO Charlie (of course) with a tubed output. FM in Oneonta NY sucks ? that?s why I added an SONY XM radio tuner (not half bad). 



The device on the rug in front of the center speaker is the best antidote to bad sound that I've found.

Nuff for now - Keep your heads clean and your tails out!

MERRY CHRISTMAS

Charles

O yeah, THANKS Steve for the info on how to use Imageshack to upload and attach photos.
    



Offline xcortes

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Re: Happy Holidays to all
« Reply #1 on: December 19, 2008, 09:37:35 AM »
Good for you Charles!

I was going to ask you about the eq frequencies and Q but as they say "google is your friend":

http://www.celloseattle.com/ctdocs/prodserve/peripherals/audiopalette.html

Frequency Adjustment Controls:
25 kHz control: +/- 24 dB in 1.00 dB increments
5 kHz control: +/- 12 dB in 0.50 dB increments
2 kHz control: +/- 6 dB in 0.25 dB increments
500 Hz control: +/- 6 dB in 0.25 dB increments
120 Hz control: +/- 14.5 dB in 0.50 dB increments
15 Hz control: +/- 29 dB in 1.00 dB increments

http://www.stereophile.com/solidpreamps/692cello/index.html



And happy holidays to you too!

Xavier Cortes

Offline classicrecordings

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Re: Happy Holidays to all
« Reply #2 on: December 19, 2008, 11:09:05 AM »
Finally, a few words about my current system ? speakers are Quad 63?s driven by a tweaked Lazarus Class A hybrid 50 watt amplifier.  Homebrew, center channel, Quad woofer with self contained combiner / amplifier / 4th order low pass filter from 100 hz down.  System goes down into the 20?s. 




You are a man after my own heart.  I have been thinking of using 3 Quad ESL 63's in my main system.  I would love to hear how it is working out and how much of a difference there is once you add in the center speaker.

David
David Stangret
HK Citation 1 Pre-amp, Thorens TD-124, Ortofon 309S arm, SPU cartridges, mono block tube amps, Ars Acoustica LaDiva speakers, and I'm still trying to decide what machine to go with.
http://www.classicrecordings.ca

Offline ironbut

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Re: Happy Holidays to all
« Reply #3 on: December 19, 2008, 12:20:30 PM »
Fantastic report Charles. I love those Quad 63's. For the benefit of our newer members, Stellavox is Charles King who wrote the original "Greening of the Revox G36" article in Audio Amateur a while back. He also wrote the original instructions for rewiring the RS1500 for direct output of the heads to the existing RCA jacks that can be found on the Bottlehead site under the Seduction phono stage. Here's a link to another great article of his adventures in the high end; http://www.sixmoons.com/industryfeatures/oswaldmill08/oswald.html
Those of you who have an interest in restoring an old G36 would do well to search out his original article. He never seems to be lacking in truly interesting projects.
Charles, like I said before, I was very impressed with the Audio Palette when I got the loan of one for a bit. Every once in a while I see one for sale but still at mind numbing prices (for a used eq at least). I've wondered if taking a couple of channels of eq from a mixing console or outboard studio eq and upgrading the parts could come close to a Palette? I'm sure you must've mapped that circuit pretty thoroughly. What's the key to it's transparency? As I recall, another thing that I really liked about the unit was the ease of use (frequency points and bandwidth?).
BTW I was wondering if you found your notes on upgrading the record section of the RS1500? If I recall correctly, you said that you'd replaced the coupling caps and while I not very good at reading schematics, it looks like the record amp has 8 transistors coupled with C136-C144. Does that sound about right?
Well, I think I've bombarded you with enough questions for now,..
Keep up the good work and don't be such a stranger.
steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
 HE Audio Jades

Offline stellavox

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Re: Happy Holidays to all
« Reply #4 on: December 20, 2008, 06:44:21 AM »
David, regarding the Quad setup - of course it sounds great, what else would I say.  Honestly though, the woofer work was triggered by rebuilding and listening to a pair of 989's in the room.  I can see why Quad produced them and why other folks try doubling up on the 63's (and 56's for that matter). The extra bass is worth the experiment [it is axiomatic that guys can't get enough bass].  Since it's mostly mono I figured I could get away with a single center channel speaker - but set back 18" or so to (hopefully) preserve the time alignment.  No cone woofer can match the speed.  By the way it uses four full range panels (not the ones with the semi-circular rings).  Now if I could find the supports for a 989 to build a six panel unit!!!!!.

Steve, email me separately about the equalizer.  Regarding the Technics record - from the 1520 manual, the caps (in one channel) are C 113,116,121,124,129 and 134.  If you won't be needing/using a mike level inout, I'd look into bringing the high level input directly into the record level pot which could eliminate 113 and 116.

Cold where you are?

Charles 

Offline ironbut

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Re: Happy Holidays to all
« Reply #5 on: December 20, 2008, 12:30:10 PM »
Thanks Charles. That info about the Technics is really great. The weather here is a little cold for N.Cal but since I used to live in your neck of the woods (NW NY) it's tropical in contrast. I can tell by the airline delays that you guys are getting hit hard.
I agree with you about electrostatic mid bass especially. Folks who've never experienced the speed and snap that a large panel can produce are always shocked when they hear it for the first time. It's really hard to listen to anything else once you've been spoiled by it. I demoed the newest smaller Quads in my system when they first came out (love the new look) and they're very nice too. The same shop that loaned them to me has a pair that they drive with a pair of 211 mono blocks and it's wonderful.
steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
 HE Audio Jades