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    Posted: 27 Feb 2019 at 10:46pm
Hello all! 
And ThankYou! for the chance to possibly add a little, from a different view[point]! 
I have been going through a bit of "six degree's of separation" all because of the Ceramic Cartridge that Mr Slee found and put it up against the idea of RIAA/Magnetic use of Cartridges giving us a platform that we are happy enough to walk on until someone comes and resurfaces the platform with carpet! Well, almost! 
I read with amazement the Forum Topic: questioning-phono-sanity_topic1370_ where the Sonotone 9TA[HC or not] was found to give a wonderful account of itself. I first came across this cartridge when I had to do repairs to an old Kriesler Model 11-95 that has a Garrard Type AT6 Turntable, 9TA SD Diamond Stylus. Going on UK ebay where the best Turntable Spares are found [I think..?] I was surprised to find this Cartridge, New! and in quantity! Degree 2! Being interested in HiFi, Turntables [which I try and do repairs on and get new Stylus for] and having made the Moving Coil version of the Silicon Chip Phono Preamp; I was ecstatic to find that Mr Graham Slee [famous in my books!] had a Kit I could make! Then doing a further search on the Customers Kriesler, I find myself back on this website on the subject of the 9TA! Click in another degree! 
 Remembering I had an old Valve Book that had Schematics in the back, I would like to ask Mr Slee if he had seen the "PREAMPLIFIER FOR CERAMIC PHONOGRAPH PICKUP" schematic in the RCA RECEIVING TUBE MANUAL? It uses a single 6J7 valve in a Cathode-Follower (Low Impedance) Output design. 
 Seeing that I have come to the bottom of my writing space, I will leave it there for now, being a very happy chappy to be able to make a contribution, hopefully of some worth! Wink
Kind Regards,
DogBox [Steve]    
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 7:31am
Hi Steve, welcome (and by the way the box expands to fit your writing so please keep going).

I'm taking a wild guess here, but I think you may be upset with me because you expected to see a circuit/product that would preamp the 9TA?

I can put that right. And even before I get in drawing mode I can point you at this magazine: https://www.americanradiohistory.com/Archive-Practical/Wireless/70s/PW-1976-07.pdf - you need page 229 (39 in your browser page counter).

It should cost less than £10 in parts, and can be easily modified to work on two E-cell 9 volt batteries wired in series. Just remove R17 (15k resistor) and take the positive supply to R13-C9 junction. Making C9 100uF will improve matters using a battery supply.

The components are numbered such that it makes 4 channels which is 2 stereo channels because it was intended for a twin-deck. Obviously you only need 2 channels. C5 isn't really required as the cartridge itself blocks DC because it is the equivalent of a 600pF capacitor. C1 should be better than a ceramic, and a 47pF polystyrene should be more suited. The BC184 transistor (as well as all the other bits) is available from Rapid Electronics, but I used a BC109.

I built this in July 1976 after constructing the PW Easy-build Disco, and it sounded good to me at the time (aged 21).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DogBox Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 10:15am
...I think you may be upset with me.." who me? LOL No way! 
I was just wondering if you had seen the RCA schematic and 'their take' on a preamp using a valve? 
Was going to try and upload it if you wanted/thought worth it? 
 I am definately not clever enough to be even get a 'bit miffed' - maybe envious at your talent - but have no reason to be angry.. 
 Actually, thinking about how the industry went about recording, I seem to remember learning from that silicon chip build that Decca had their "ffss" Full Frequency Stereophonic Sound that they cut their records to, so you had to alter the RIAA filtering to suit. I found your article really interesting and was waiting for your take on promoting Ceramic Cartridges - even suggesting a design and a preamp to go with it that would revolutionize our record playing experience! I saw you make a prototype preamp.. didn't it inspire you enough to 'run with it a little more..?' I think the question still remains: Is "magnetism" the "best driving force" for vinyl replay..? Is there No Other method for generating a voltage from the patterning groove laid down by the cutting lathe of sound recording...? MM & MC both use magnets. Isn't the Ceramic Pickup able to do "just as good a job" of sound retrival? if not "cleaner" by not having magnets to assist and skewing frequency..? 
 Thankyou! so much for your warm welcome and I think you would make a great electronics teacher! I've already learnt a heap! Now i'll go and check out that magazine you suggested. Thanks! 
Kind Regards,
DogBox   
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 10:04pm
Originally posted by DogBox DogBox wrote:

...just wondering if you had seen the RCA schematic and 'their take' on a preamp using a valve?


I think I may have that in one of my books: "The preamplifier uses a 7199 triode-pentode in a high-gain pentode input stage..."? If not that one I'd be interested in seeing it.

Originally posted by DogBox DogBox wrote:

I seem to remember learning from that silicon chip build that Decca had their "ffss" Full Frequency Stereophonic Sound that they cut their records to, so you had to alter the RIAA filtering to suit.


Perhaps they meant FFRR? It preceded RIAA and had an upper time constant of 50uS so RIAA (75uS) makes it sound a little dull.

Originally posted by DogBox DogBox wrote:

I found your article really interesting and was waiting for your take on promoting Ceramic Cartridges - even suggesting a design and a preamp to go with it that would revolutionize our record playing experience! I saw you make a prototype preamp.. Didn’t it inspire you enough to 'run with it a little more..?' I think the question still remains: Is "magnetism" the "best driving force" for vinyl replay..? Is there No Other method for generating a voltage from the patterning groove laid down by the cutting lathe of sound recording...? MM & MC both use magnets. Isn't the Ceramic Pickup able to do "just as good a job" of sound retrieval? if not "cleaner" by not having magnets to assist and skewing frequency..?


What could have driven me on to 'run with it' would have been interest from a cartridge manufacturer (third party OEM, that sort of thing). I tried a contact or two but they thought it a crazy idea. But with some modern engineering of the type that goes into MMs or MCs; some good suspension and some better piezo material, it could use a modern type diamond stylus, and might perform as good.

A ceramic gives higher output and best of all, it's flat, whereas a magnetic has a rising response (constant velocity), and would only need the record's own EQ. Instead, with magnetics we have all kinds of noise and gain problems to overcome, as well as EQ'ing the cartridge.

To try and keep up with sales, Sonotone started making ceramics with a built in equaliser to make them output the same as a MM, which basically meant making matters worse. It died. (http://www.roger-russell.com/sonopg/sonopc.htm)

In the end I decided to turn the tables (pun unintended) and put a magnetic equaliser on the front end of a ceramic EQ stage, applied for a patent (and got it), and called it an Accession.

Originally posted by DogBox DogBox wrote:

I think you would make a great electronics teacher! I've already learnt a heap!

I'm far too unorganized for that, although it isn't the first time somebody suggested it. But I'm well past teacher retirement age, and sometimes I have to look-up things I should be able to remember Embarrassed

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Post Options Post Options   Thanks (0) Thanks(0)   Quote DogBox Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 11:01pm
Graham said:think I may have that in one of my books: "The preamplifier uses a 7199 triode-pentode in a high-gain pentode input stage..."? If not that one I'd be interested in seeing it. 
Tried to upload but my dinosaur vista operated thingy-majig will only do PDF Confused Cry 
 However, it uses a 6J7 in a Cathode-Follower Output. The 6J7 is a "Sharp Cut-Off Pentode" which can also be used in a Triode Connection. 
The schematic shows an AF output of 50kOhms..?? Which from previous readings seems high..??? 
 I sent the schematic by email and hope you may be able to help everyone else to see the diagram? 
Also, haven't met a Teacher that had a perfect memory yet! Wink So You'll do fine! 
Kind Regards,
DogBox [Steve] 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar 2019 at 9:01am
Thanks. Got it, and here it is:

Preamplifier for Ceramic Pick Up Cartridge
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar 2019 at 10:08am
As you can see, it's a cathode follower... Confused

Funny, isn't that thing at the top the plate or anode? And a 10n cap connects it to the output? A 50k load? Bass cut from 318 Hz! Yuk!

So where does the cathode go? To the suppresser grid, and via C1 to the screen grid, which is connected via R3 to HT.

So I think we can agree it isn't a cathode follower?



Edited by Graham Slee - 01 Mar 2019 at 10:11am
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