Lou Dorren: A new CD-4 Demodulator!!! [ARCHIVE]

[jrlinks]

I would imagine there will be plenty of action on eBay CD-4 sales once this is shipped.
Stock up now.
You may still find minty fresh shrink-wrapped copies of your favorite titles. (or a test disc)

 

[The Quadfather]

Tektaff, I believe Lou has already published the schematics. See earlier posts in this thread. But I suspect there will be written material. Jrlinks, the new demodulator uses FM radio type limiting principles, so a carrier level control pot is not necessary. Just plug and play!

The Quadfather

 

[jrlinks]

'Just plug and play!'
So no need for a setup disc now?
Or would it still be a useful adjunct for setting the separation controls?

 

[Quadwreck]

Maybe I missed it, but I still haven't found a price estimate on this.

 

[The Quadfather]

A setup disc could be used to adjust the separation. But it is not necessary. I generally use a Doobie Bros (Tolouse Street) album. They have good separation that is easy to hear. As I recall, the price was also discussed in the early postings of this thread. I believe somewhere around $500.00 . It was a graduated scale depending on the number of units ordered, and the criteria for the cheapest price has been met.

The Quadfather

 

[Quadwreck]

Thanks. At $500 or so, I'm in.

 

[jrlinks]

Will I need to replace my tonearm RCA interconnects with new low capacitance cable
for use with MM type cartridges?
If so how do I determine the correct cable to buy?

 

[erniegiro]

Will I need to replace my tonearm RCA interconnects with new low capacitance cable
for use with MM type cartridges?
If so how do I determine the correct cable to buy?

If I remember correctly, Grado cartridges are immune to changes in cable capacitance.

Maybe Master Dorren or other forum posters can confirm this for us.

One reason I was so happy to hear the demod was going to come with a Grado cartridge was to avoid any doubts I have as far as the cable capacitance of my Sony TT, i'ts at 100pF and that's right at the upper limit of what's allowable and still have good CD-4 performance.

 

[dlaloum]

Yes - I did a series of tests on a Grado Gold1 that I own, capacitance had negligible effect... although lower resistive load seemed to improve sound marginally (for stereo)

I am not sure whether 100k load will be needed with the Grado either.... and the Grados do tend to perform better at around 10k to 15k resistive load (for stereo).

I am continuing to wait with great impatience for the full review of the first unit...

 

[erniegiro]

dlaloum, thanks for the info, I'm also anxiously waiting on the first review!

 

[jrlinks]

Crickets, and only in stereo at that!
I need a new shiny Xmas present.

 

[dlaloum]

Any word on the cantilever that will be fitted to these Grado cartridges? and the Stylus fixing type/style?

Will it be on a par with the Grado 8MZ?
Nude or bonded?

Bye for now

David

 

[jrlinks]

Don't hate me for asking this.
My Onkyo receiver in direct analogue mode has no trim controls
for channel balance.
Does the new demod have outputs with trim?
I ask because I have already decided that one of my 3 CD-4 AT cartridges
can not be used because the left channel is down by 2.75db
No, not a stylus problem, the generator coils are not balanced.

 

[Quadzilla]

Which Audio Technica has the problem? There are lots of AT cartridge bodies floating around out there. Why not look for a replacement body? They are usually pretty cheap, because the stylus is the expensive bit. I got my AT20Sa body for $25 worth of used jazz LPs (I hate jazz anyway), and the guy was happy to get rid of it. I found a brand new genuine ATN20 stylus for $100 with shipping, and I haven't looked back.

 

[jrlinks]

My question was about output trim on the new demod.
I'm sure most users would not bother to measure the channel balance
of their cartridge as I do.
For what it's worth I have an AT20ss, an AT15ss, and 2 AT14Sa.
I had to retire one of the AT14Sa bodies due to the left channel loss.
The others are within .75 db.

 

[Quadzilla]

Sorry ... never mind.

 

[gcalo]

do we know how many RCA inputs there wll be? More than one set?

What about additional inputs (equalized) for reel2reel inputs (with switching) for Project3 and some other 4 channel tapes?

maybe this was discussed and I missed it?

 

[DennisMabry]

do we know how many RCA inputs there wll be? More than one set?

What about additional inputs (equalized) for reel2reel inputs (with switching) for Project3 and some other 4 channel tapes?

maybe this was discussed and I missed it?

Post #467 shows the front and back design;
https://www.quadraphonicquad.com/fo...5-Lou-Dorren-A-new-CD-4-Demodulator!!!/page19

Photo of prototype;
https://www.quadraphonicquad.com/fo...st-Look-at-the-New-CD-4-Demodulator-Prototype

 

[gcalo]

Thank you for that info, Dennis

I need all the help I can get!

 

[jrlinks]

I just received my QSI record cleaning set
And like at least one other member here
NO instructions for use are included.
Anyone point me to a PDF for this please?

Got cleaning instructions I needed from Lou.
All is well.
James