CA/BA-F1 Questions From a Newbie

So, who knows of a good source of replacements for the caps, and what type would be best? Also are the original caps polarized, as I don't see any markings that would suggest they are?
NP0/C0G disc ceramic capacitors. you can find them in mouser and digi-key
 
Thanks, but I checked both Mouser and Digi-Key and neither one seems to carry 2,3, or 22 pF 125 volt C0G (NP0) caps. They only seem to have much higher pF values and at lower or much higher voltages. For instance 3 and 22 pF 1000 volt 5% C0G (NP0), but no 2 pF caps at Mouser.

I've noticed that they are available in 1%, 5%, and 10% tolerances. There doesn't seem to be any mention of the original Black Flag cap's tolerances in the Sansui Schematics. I assume the tighter the tolerance the better?

Any other possibilities for sources [particularly the 2 pF size]?
 
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If 100 volts is safe to use these look like the best available:
 

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Thanks for replying.
Both units appear to be in excellent condition, and sound very good hooked up via the AC inputs and played back thru Infinity Reference Standard 1.5 speakers.

I have a Fluke 77 Digital Multi-meter that has a 0-1000v DC scale reading down to 1/1000 of a volt [in the 3.2 V DC range, resolution is .001 V, and accuracy is +-(0.5+1) ]. The meter also has a 300mV DC function [Manual says: "Select the 300 mV DC function for best resolution below 320 mV DC" [in the 320 mV DC range, resolution is 0.1 mV, and accuracy is +-(0.5+1) ]]. Specs Attached for Fluke 77.

Also not sure if it would exist happily in an AC circuit in DC mode. Would the measurements have to be taken "under load" to be useful, and with or without actual music?
No, DC offset does not need to be done under load.
With this pair I would be using DC.
 
As for the Equalizer. Are the line levels between Amp and Pre-Amp not compatible with Equalizers?

Now that I think about it, I do seem to remember having a 12 band equalizer 30-40 years ago that was built from a kit by Synergistic Sounds, and when building it you had to make a choice between using it in the Tape loop or between the Pre-Amp and Amp. There were a few minor changes to some of the components [but I can't remember any of the details at this point, and the paperwork is out there in Never-Never Land if it even still exists]. But the advantage of having it between Pre-Amp and Amp was that you could tune your system to your specific environment and speakers with a "Pink Noise" source using the calibrated mic that came with the Sansui SE-9 Equalizer and its 8 band/channel real time display. And, of course, this would result in all your sources [tapes, vinyl, tuner] getting an almost neutral environment to play back in. The Synergistic Sounds Equalizer got torched in a house fire 9 years ago [mostly smoke damage and possibly some heat] but I still have the actual unit itself. I suppose it might be salvageable, tho I might have to change out the 24 slide pots as they where mostly plastic cased, and as I mentioned before, I haven't seen any of the documentation since the fire.
Don't worry about the EQ for now, you'll find you probably dont need it.
Due to the nature of EQ filters, you'll be adding colouration and distortion to the performance of this system.
Most if not all domestic type EQ's are designed to run in the Tape Loops, this is how their sensitivity is set up, if you put it in line with the pre-amp power-amp you will run out of headroom in the EQ and system will be noisy.
Most Professional EQ's are designed around +4dbu standard, so in this case you could use one between the Pre-amp/Power-amp, some have a -10dbu option on them too....
But like I said, don't worry about EQ at this point, I hate graphic EQ's, they are crude, noisy, and rarely improve a system.
That one with the cheap analyser mic, forget it, it doesn't work that well. To do it properly you need a professional setup with FFT which runs into thousands of dollars....
In my opinion those SE-9 type things are toys...
 
If 100 volts is safe to use these look like the best available:
Yep, they'll be fine.
Low values you need to use 1% I used 0.5% Silver Mica all 500V.....

You don't need close tolerance capacitors for this purpose, in a tuner you do, but these are for audio amplifier stability purposes.

Silver mica 1% or 0.5% capacitors are expensive and unnecessary in this application.
 
You don't need close tolerance capacitors for this purpose, in a tuner you do, but these are for audio amplifier stability purposes.

Silver mica capacitors are expensive and unnecessary in this application.
Well, carry on then......I will take my unnecessary silver Mica caps somewhere else.....
 
Well, carry on then......I will take my unnecessary silver Mica caps somewhere else.....

I still have Silver Mica capacitors in my AU-919, and I won't be taking them out anytime soon. On the advice and guidance of some of the luminaries of AK, for subsequent restores including a BA-F1, I have realised that for a number of reasons, not the least being price, that ceramic NP0/COG are better.
 
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I still have Silver Mica capacitors in my AU-919, and I won't be taking them out anytime soon. On the advice and guidance of some of the luminaries of AK, for subsequent restores including a BA-F1, I have realised that for a number of reasons, not the least being price, that ceramic NP0/COG are better.
I went that way, because in those Crown Macro-Tech's which occupy a lot of my time, they use 1 and 0.5% Silver mica for that exact application, I figured there was a reason they chose that particular dielectric....
But, yes they are not the cheapest....
 
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I went that way, because in those Crown Macro-Tech's which occupy a lot of my time, they use 1 and 0.5% Silver mica for that exact application, I figured there was a reason they chose that particular dielectric....
But, yes they are not the cheapest....
That's an understandable and good reason to use Silver Mica 1% or 0.5% (10x6mm) with maybe 1pf or 2pF of strays, as compared to Ceramic NP0/COG, 12.5%, (2x2mm) and virtually '0' strays, at about 20% of the price.
 
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That's an understandable and good reason to use Silver Mica 1% or 0.5% (10x6mm) with maybe 1pf or 2pF of strays, as compared to Ceramic NP0/COG, 12.5%, (2x2mm) and virtually '0' strays, at about 20% of the price.
I realised after the exercise I could have done it that way!! That damned Hindsight thing again!!
 
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Thanks again Kevzep and Hyperion. I gather that after the Black Flag caps are replaced there needs to be some sort of re-calibration of both the CA & Ba-F1? Is that a DIY thing or something to be done at a tech shop?
 
Thanks again Kevzep and Hyperion. I gather that after the Black Flag caps are replaced there needs to be some sort of re-calibration of both the CA & Ba-F1? Is that a DIY thing or something to be done at a tech shop?
No you can just fit them and you are good to go....
 
Well, that will certainly save a lot of hassle.

I've had to order a step down transformer from 120 volts to 100 volts [1000 watts] to accommodate these units and was wondering how likely it will be to introduce electrical noise into the system. I have some fairly good AC line noise filters but they are designed for 120 volts and I'm not sure if I can use them between the step down transformer and the CA & Ba-F1 on the 100 volt side.
 
Well, that will certainly save a lot of hassle.

I've had to order a step down transformer from 120 volts to 100 volts [1000 watts] to accommodate these units and was wondering how likely it will be to introduce electrical noise into the system. I have some fairly good AC line noise filters but they are designed for 120 volts and I'm not sure if I can use them between the step down transformer and the CA & Ba-F1 on the 100 volt side.
Just try it and see how it is.....
Might be okay....there's a lot of filtering in the amplifier...
 
I used npo/cog's in my AU-919 even though my heart said silver mica's due to a mean old billfold that refused to pay for the top shelf parts, no harm no foul and the amp sounds great.
Either way the comments to get the old black flag caps out of the amp is very very sound advice, as you start to go through things you may find them to be soft gooey falling apart disasters in waiting.
-Lee
 
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