What is Monaural, Dual mono, stereo in fact?

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oszkar

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Joined 2013
Measurement taken from filament to end top of the rotating pot axle, 2,2 cm axle length. With the filament it is 2,5cm.
I will appeal to a friend in the electronics repair field to supply me with a couple of these.
In the meantime, can someone advise in modding my Technics SL-PG500A CD-Player? Is it worth? I have options of buy for Kenwood DP-7050, Onkyo DX-706, Sony CDP-970. I had recently a Kenwood DP-1100B and it sounded warm and lovely but the lens is dying!
 

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djmeverett

djmeverett

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Here's a good spec sheet for Bourns pots that might help you find the correct standard dimensions etc. There are several MFG's for pots like these so you should be able to find the right one comparing the two you have in there with these.
50kR, dual gang with PC board pins and the right shaft spline/length are the critical measurements.
You did mention that they were "stepped" or switched and not "continuous"...which might not be potentiometers but actually rotary switches.
 

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oszkar

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Seen your message! Went to the radio shack today and got two of these 50k x2 pots! Once fitted by trial, measurement and first look the caps for the pots will fit just right, no left - right movement, so that should be good. I'll say! By sunday will have them fitted in! Until then, what happens if I replace the lamps inside with led's, for the indicators that is? I replaced before one such lamp in a Technics RS-AZ7 Cassette deck, painted it in greea and worked like a charm and still does very good this day as well!
 

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oszkar

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In the meantime, what should i get to make my technics SL-PG500A sound more darker it is transparent and bright! I also have a DP-1100B Kenwood, sounds like I am in love with it but it's laser recons only some original and burned cd's, on one burned CD it read 3 Tracks out of the 8 Tracks TOC, than read through all tracks. I could borrow a 20 Mhz Oscilloscope from a friend if it is a worthy job!
 
danielwritesbac

danielwritesbac

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startfetch.com
In regards to post 50 and 51, the trouble there is "comb filtering" which is a raspy bright noise. Little coin size tweeters can be put close enough together to prevent that; however, for the big bezel tweeters like yours, AndrewT's answer is correct at post 51.

We should always suspect that AndrewT's answer is correct. I push boundaries both high and low so that I may find the optimal middle ground eventually. He calculates that locale better than I could ever do by calculations, since I'm actually not good at math and he does it both superbly and applicably. These approaches are opposite and frequently lead to a disagreement or a lively discussion. As slow as my approach may be, I can prove practically that most of what he says is true. That bit might not be fascinating; However, what is really very interesting is that in cases when he and I agree, that is as close to a guarantee as you can ever get, and that tweeter arrangement is wrong.

Therefore, please don't make critical judgements based on the output of those speakers. Comb filtering distortion is unpleasant and that arrangement will cause it. If you had desired to use parallel tweeters, those bezels are far too big--they keep the elements too far separated and this distance will cause brash distortion.

In regards to CD player incompatibility with CDRW, try different brands and never write music CDs faster than 16x. Here in the USA, inexpensive sony branded cmc mag which just happens to have the codes (inside the CDRW blank) set for "Maximum is 16X" even though that package advertisement says 52X. It is very popular and considered reliable, even though the media is "lowest bidder" and that's because it routinely burns at 16x or lower. Sneaky! And effective!

In regards to darker sound, try a capmulti, like Kmultipler, in the power circuit. A capacitive multiplier is unavoidably a virtual inductor, which will naturally throw away all of the "brash" tones. That is not my taste; however, it is doable and it works very well. I like the Kmultipler when it is followed by "tracking pre-regulator" to freshen the sound. Perhaps Kmultiplier followed by discrete reg may be optimal.
 
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oszkar

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The big ones are for loud music and they do good. I listen to music for aspects and impresions on the Heco Alegro 350 i think they are, Dappolito design. I want the cd player mod with the multiplier and tracking preregulator. That is what I am after. BTW is it something bad wrong with my DP-1100 since it does not read only one original copy and a burned cd at 16X? Could I open up the Laser cartrige in pieces to clean all prisms.
 
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djmeverett

djmeverett

Member
Joined 2011
oszkar said:
Seen your message! Went to the radio shack today and got two of these 50k x2 pots! Once fitted by trial, measurement and first look the caps for the pots will fit just right, no left - right movement, so that should be good. I'll say! By sunday will have them fitted in! Until then, what happens if I replace the lamps inside with led's, for the indicators that is? I replaced before one such lamp in a Technics RS-AZ7 Cassette deck, painted it in greea and worked like a charm and still does very good this day as well!
Click to expand...

The incandescent lamps in there (3) are listed as 24V 40ma lamps so I think you could use the LED's with a 1k - 1.2K 1W dropping resistor in series. Depends on the LED spec of course to get the exact value but that should be close.
 
danielwritesbac

danielwritesbac

Member
Joined 2007
startfetch.com
Not enough information.
Firstly, what is the color of the LED?
Typical forward voltage drop.
Red 1.6v, yellow 1.8v, orange 2v, white 3.1v
We will need to put that into the calculator at post #72.
That size led is typically 20ma max peak, of which we should derate to 40%, about 8ma.
We will also need to put that into the calculator at post #72.
The power supply voltage given is 24v. Did you measure? Is it DC?
We will also need to put the measured voltage into the calculator at post #72.
Now then what does the calculator say to use for resistor values?

Quality control: With the LED safely lit up, measure the voltage across it to double-check the forward voltage drop estimate, and re-calculate with the accurate real forward voltage to see that we didn't pass 8.6ma.

P.S.
It may take at least 6 led's to replace a light bulb.
 
djmeverett

djmeverett

Member
Joined 2011
oszkar said:
Yes, I did! Only the Phono Stage Light(Green Light) and the Recording Indicator(red line) are still bulbs! The tones work flawlessly.
Click to expand...

Were you able to take those measurements that Daniel mentioned on the LED's and resistors?
It might be something to double check after they've been on for awhile because like he said they could be running a little high in the current department and might get hot. You said those were 10watt resistors in the pic but they looked like 1/2watt or maybe 1watt...???
Anyway good to see and hear it is back in good condition.
 
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