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CA/BA-F1 Questions From a Newbie

Discussion in 'Exclusively Sansui' started by P.Bear, Jul 3, 2018.

  1. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Just bought a CA/BA-F1 set and cannot find anything in the manual or sales literature that specifically states that the CA-F1 can be plugged into the BA-F1 using the DC input jacks instead of the AC input jacks. It would make sense that you can, given they were designed to work together, but it would be comforting to see it in black & white somewhere.

    Also, can you insert a 10 or 12 band equalizer in line between the CA-F1 and the BA-F1, and does that change which input jacks you should use on the BA-F1 [DC vs AC]? I have several candidate equalizers on hand such as the 12 band/channel Pioneer SG-9800, or the 10 band/channel TEAC EQA-3 or TEAC EQA-10, and finally the 8 band/channel Sansui SE-9 computer run equalizer. And same question pertaining to the AU-717 pre-amp/amp, inserting between the pre-amp and amp section as well as what would be the appropriate switch position [with or without caps]?

    I would prefer not to fry anything if possible.
     
    Last edited: Jul 3, 2018

     

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  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
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    Location:
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    The safest - especially for an 'unknown condition' piece of gear (as is the case here?) is to use the AC inputs.

    If you know how to measure the DC output from the CA-F1 and it shows as very low or non-existent - then you can improve your listening experience and use the DC inputs to the BA-F1.

    Don't be so keen to hook up an equaliser - you may find you don't need it. And regarding where to connect the EQ if you do use one - between the pre-amplifier and the amplifier is the wrong place. I think you will find that the tape loop connections are the correct place.
     
    Last edited: Jul 4, 2018
  3. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    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?
     

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  4. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, 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.
     
    Last edited: Jul 4, 2018
  5. ghamilton

    ghamilton Super Member

    Messages:
    1,497
    Location:
    ASHEBORO NC
    Before you go any further you need to find out if all those "BLACK FLAG" caps have been replaced. That combo is very special and you need to know it's history.
     
  6. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Greetings, and to which BLACK FLAG caps are we referring, and in which unit? The Synergistic Sounds Equalizer, the Sansui SE-9, the Sansui CA-F1, or the Sansui BA-F1?
     

     

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  7. markkb

    markkb Active Member

    Messages:
    201
    Location:
    Mountain View, CA
    The CAF1 and BAF1. Do a search for black flag capacitor (replacement). Apparently it’s not a matter of “if” but rather “when” those caps will fail. When failure occurs they can take out the precious outputs. The original outputs on the BAF1 are no longer available. If the units still have the black flags, (they’re small and look like little black flags) many folks would recommend to replace right away, rather than tempt fate.
    Here’s a start:

    http://conradhoffman.com/BF_caps.htm
     
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  8. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Thanks markkb, I see frequent references to the BA-F1 but not the CA-F1. Also do you know if the BLACK FLAG warning applies to the AU-717's as well?
     
  9. ghamilton

    ghamilton Super Member

    Messages:
    1,497
    Location:
    ASHEBORO NC
    No black flags in the 717.
     
  10. markkb

    markkb Active Member

    Messages:
    201
    Location:
    Mountain View, CA
    Sorry I should have just referred to what I know, the BAF1. Look into the BAF1, and identify the black flag capacitors (unless someone has already changed them out). Then pop the hood of the CAF1 to verify in your unit.

    Post a picture if your unsure.

    That’s a preamp I’d like to get some day. Nice pre amp and amp set.
    Also when your looking into your BAF1, see if you can identify what the output transistors are. Are they the unobtanium NMA1012 and the NMC1012? If so your lucky.
     
  11. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Thanks to you both [ghamilton & markkb].. I'm glad I at least don't have to worry about the AU-717. I'll do a little snooping around in the BA-F1, and I guess the CA-F1 just to be safe. I did get a service manual as well, and it appears to cover many different versions of the BA-F1, at least from a supply voltage stand point.

    I should have mentioned that the CA/BA pair are Japanese versions, with a back panel label saying they are 100 volts AC, but with a label placed over it saying 120 volts AC. I don't yet know if this means someone rewired the power inputs on the power transformer or not, but the dealer claimed they "ran fine" on 117 volts AC.
     

     

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  12. Sansuiman

    Sansuiman Active Member

    Messages:
    387
    Location:
    St. Louis, Missouri
    ^ be careful regarding the line voltage. Unless the transformer was changed to one with a 120VAC primary, you will be running it too "hot". All Sansui Japan domestic market units were fitted for 100V only and were not reconfugurable for alternate line voltages.

    Therefore, transformer replacement was needed for use at a different input voltage. This could be accommodated by a Sansui service rep back when factory parts were available but it's about 40 years too late for that. If an official change was made at a service center, there should be a round foil sticker showing 120V placed on the unit. Of course, a step down can be used if needed, but that is a bit of a bother as well as added expense.

    JDM models are easily identified as well by having much of the information on the rear panel printed in Japanese, rather than English as with all other versions, irrespective of the language spoken in the destination market.
     
  13. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Thank you Sansuiman. So the JDM models don't have multi tap transformers as shown in the [English language] service manuals?

    The back panels are pretty much all in Japanese, and I see no round foil stickers. There is just a stick on 120 volt label which appears to have been made with a Brother type label maker covering the original 100 volt label. Would a 1000 watt step down transformer have sufficient margin to run both the CA-F1 and BA-F1 should it turn out they have the original 100 volt transformers?
     
  14. Sansuiman

    Sansuiman Active Member

    Messages:
    387
    Location:
    St. Louis, Missouri
    Sansui did some weird stuff earlier on (pre 1972 or so) with JDM models, but they are seldom seen here in the US. By the time the BA/CA-F1 combo was made all the gear made for sale in Japan was 100V 50Hz only, no multi-tap as far as I've ever seen. There were usually several versions of a given model made, based on the intended destination market:

    - JDM, 100V 50 hz only, no voltage change on-unit.
    - US 117V 60hz only (had to meet UL specs and thus had a 117V input only power transformer, no voltage change possible on-unit)
    - CSA approved model for Canadian market. Much like US version, but often with additional fusing installed internally. Again, no voltage change possible on-unit.
    -UK, 240VAC 50Hz primaries, no convenience outlets on rear panel due to the high line voltage and British safety requirements. Some of these did have selectable voltage but appears hit or miss based on year made. May have been evolving safety requirements in the UK accounted for this.
    - European market export version, 220V 50hz, cord fitted varied by destination country. May have selectable voltage dependent on model and year of manufacture.
    -XX, general export version, usually fitted with a US style plug (two vertical blades, ungrounded) and selectable for 100/120/220/240VAC at 50 or 60Hz. These were the units that were sold to US military in the on base exchange, so the units could be used almost anywhere they were stationed. Also were sold for markets without any other specific sub-variant, provided local safety standards didn't prohibit sale of units so equipped.

    By the early 80's, Sansui added a few other export variants, for South Africa, and certain South American markets. These are referenced in some service manuals of the era, but I can't speak to specific attributes of these versions, having not seen any in person.

    Anyway, it doesn't sound like your amp had an official change made, with the P-touch label applied. Unless who ever did that actually found a factory 120V power transformer for the BA-F1 (and for the preamp as well) and installed them, I'd assume they are still equipped for 100V operation unless it can be determined otherwise.

    Some 100V equipment will appear to work ok at 110-115 volts, but it is very risky and will almost certainly shorten the lifespan of the unit even if no major problems are evident in operation, thus deifitnely not recommended. For that matter, depending on where you are and your local electric utility, US line voltage can be as high as 127V and still be technically in spec. That's a big jump from 100V, and things start smoking at the kind of over-voltage.

    A step down, if employed, needs some "breathing room" over and above the rated consumption of the load attached so at least a 1000W for a BA/CA-F1 combo would be appropriate if these units are in fact still 100V. If you're lucky, the voltage has been properly changed on both units for 120V.
     
  15. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Thanks, but I won't be holding my breath till I can look under the hood!

    Meanwhile, any thoughts on measuring the outputs of the CA-F1 [and potentially some of the equalizers] for DC output with a Fluke 77 meter [see #'s 1-3 above],[so as to be able to safely utilize the DC inputs on the BA-F1]?

    Or how about the question as to whether or not you can put any equalizer between the CA-F1 and the BA-F1 or if it must be specifically designed to go there [see #'s 1-4 above]?
     
  16. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

    Messages:
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    Location:
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    First off I don't know why the push to start ripping apart a amp when you think it sounds good now, enjoy it.

    You don't run the CA-F1 preouts to the EQ inputs and the EQ outputs to the power amp, it's just not done that way.

    You use the Tape input/outputs, that's called a tape loop. You can have the EQ in or out of the system with a flip of a switch. Personally I think you would be better without it.
     
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  17. kevzep

    kevzep Its all about the Music Subscriber

    Because, if you run this amplifier with the known extremely unreliable and unstable "Black Flag" capacitors, its likely in a very short time to have a catastrophic failure.
    Over time those caps become very unstable, and due to the high speed nature of this amplifier, when it fails, it will take out irreplaceable output transistors and other components.
     
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  18. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Hey guys, thanks for your input.

    I just got under the hood of the BA-F1:
    The Bad News
    1] It has a single voltage transformer at 100 volts [Part # PT-701, Stock # 4003071].

    2] I have so far counted 10 BLACK FLAG caps [4x 2pF, 4x 3pF, and 2x 22pF all 125volt]. Can't see any others, but I haven't shifted any of the boards so don't know what may be hiding under them.

    The Good News

    1] All 8 output transistors are originals, and judging only by the sound during the test run, working properly.
     
    Last edited: Jul 6, 2018
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  19. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    Diving into the CA-F1 now.
     
    Last edited: Jul 6, 2018
  20. P.Bear

    P.Bear New Member

    Messages:
    27
    Location:
    Washington, DC
    I just got under the hood of the CA-F1:
    The Bad News
    1] It has a single voltage toroidal transformer [Part # PT-701, Stock # 4003021], which if it follows the pattern of the BA-F1 is the 100 volt version [as the multi volt version shows as 40003020 on the schematics. However, someone put a P-touch label saying "120 volt" on the outside of the can.

    2] I have counted 10 BLACK FLAG caps [4x 3pF, and 6x 22pF all 125 volt].

    The Good News

    Only that the CA-F1 appeared to be working properly during the test run.

    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?
     
    Last edited: Jul 6, 2018

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