Thierry
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  • HI Thierry,
    I recently enjoy reading your posts about the Studer A723,I own a pair.
    I have recently had to repair them & also read your comments on the Revox forum where you discussed manufacturing the circuit boards. Do you have any boards you could sell? I would be interested in paying for these to be made again.
    thanks
    Jake
    Salut Thierry,
    Par respect, je commence par google translate.
    Je dois réviser le 1801 que j'ai acheté en 1976. Les magnétophones me fascinent, quel appareil est votre avatar.
    Dans Bose 1800 Series 1: je l'ai fait à nouveau
    utiliser EPCOS 22000uF 100V
    Comment ce choix a-t-il été déterminé? Un autre membre du forum - Aokman - a utilisé une capacité très élevée; et non sans problèmes ...
    Cordialement.
    Thierry
    Thierry
    Forgot to answer about the tape recorder, it is an AKAI GX 400D, extremely rare and quite huge ! I also have Studer tape recorders and a wonderful Schlumberger F500 that you can see here https://photos.app.goo.gl/gW3sRpKfeyviKZmW8
    Thierry
    Hi Thierry, greetings from Ireland, I am restoring a Bose 1801 and have cleaned up boards and restored chassis similar to your resto. I now have to replace the board components but I am a bit confused on resistor types as per your pics, did you use higher wattage metal film for all? Also when you replaced the ceramic caps did you use same values for your polystyrene replacements? many thanks
    Thierry
    Thierry
    Hi JS4000, apart from R3 where I tripled the wattage, all other resistors are of same wattage, only difference is that I used metal film resistors to replace all of the carbon ones. Almost all are 1/2W. For the polystyrene caps I used exactly the same values. I hope it helps. Thierry
    J
    JS4000
    Thanks Thierry! Those poly caps are pretty hard to find! Would electrolytic caps do if I cant source? Did you bother to refresh any of the diodes? I have the same rectifier and opamp as you have specced ready to drop into boards.
    Hi!

    Few days ago, my Bose 1800 series IV (CAVER PM-1400) Power Transformer has blown out. Can anyone could provide the transformer's Primary and secondary winding specification to repair this?

    Thanks!
    c) Do you know the difference between the 1800 Series V and VI? I've googled and googled and not really found anything solid. The Service Manuals seem to all be for Series VI and not V but from a few Series V photos and vids I've watched, they appear identical with the covers off. As for the internals parts, IDK. THANKS!
    Thierry
    Thierry
    As far as I know the only difference between series V and VI is, for the latter, a feature called "Sequenced power on". This allows amps to stay in in standby mode and automatically power them on one after one to avoid drawing too much current from power line.
    G
    gattaca
    Thank You!!! That is most helpful!!!
    this 420 char limit is insane..
    b) I checked your photos but did not see a part number for the 24V 2 wire fan. I've seen ADDA in other photos but not enough clarity to read them. Do you have a photo of the part number they used?
    more...
    Hi Thierry, Loved your postings on the Carver PM-1400 and Bose 1800 V/VI. I'm about to buy to a couple of the Bose 1800 Series V units to have them re-capped etc.. I have a few questions.

    a) I notice they used high-quality Nippon caps! Did you find the Nippon caps were fine even in these 21+ year old units?
    more...
    Hi Anthony, the 1600 being complex design it will be very difficult to diagnose an issue. Do you have the schematics ?
    Hi Thierry

    Im Anthony from Sri Lanka , I bought a Bose 1600 VI amplifier ,I faced same issue twice , an unusual sound from the left channel , once I repaired it and this time still struggling to
    find the fault , I need to repair this or replace the entire circuit board . Could it be possible to help me out please .

    Please email me on rajiv.fernando@hotmail.co.uk

    Thanks

    Anthony
    You nailed it..a cracked solder joint eliminating c1, cr21, cr20, and r58 from the circuit, I haven't put it under load yet...notice this amplifier inverts phase from input to output..normal? I'll put a 10 ohm load on it tomorrow and run it up a bit...Thanks..
    • Like
    Reactions: Thierry
    Thierry
    Thierry
    Hey there, glad you found the culprit. Otherwise this thing is built like a tank.
    Cheers,
    Thierry
    've got an 1800 open right now and the channel 1 heat sink goes up to 110 degrees F. with 2 leds showing from the 1k signal no load..channel 2 stays at 66 degrees F. I have to dig out my O scope, and will, but is this something you have seen? I changed the input IC on one of these channels 2 or three years ago and it worked fine for a couple years....I'll look for distortion when I get me scope out...TNX
    Thierry
    Thierry
    Yes I have seen this when something goes wrong in the global feedback loop. Can be tricky to sort out, many issues can be found. I would first investigate for dry solder joints around U1 and its passive layout parts.
    Either this channel is oscillating (ground fault) or the negative feedback loop is open somewhere. Good luck and Happy New Year
    • Like
    Reactions: jrczz
    hi Thierry- referred by Bilbo Baggins IRT my Bose 1800 Series VI pro amp.

    Right now I'm PC >> Schiit Modi Multibit (or Phono) into Schiit Freya preamp >> Bose 1800 amp >> KEF 105.4s (new Falcon caps).. The sound often seems 2D and muddled, delivers fatigue, even with HD Track quality files or LP.

    Is this common using this model in home? ..possibly a problem with the Amp, DAC/ Pre or the Listener? :D

    Patrick
    Thierry
    Thierry
    Hi Patrick,
    Sorry for very late reply.
    What you describe is strange because the 1800 VI has exactly opposite character on any system I have tried it : have you tried another source ?
    Happy New Year,
    Thierry
    Thierry
    Thierry
    As a side note, I sold 2 of my 1800 VIs to guys with various speaker systems and they describe it as a noticeable improvement in their setup (lifelike sound, lots of details and depth) hence my doubts about your sources, including DAC and preamp.
    Hello Thierry, I have read your 1801 builds and you have done some fantastic work! I have just bought one and will be doing the full overhaul, I can work from your thread pics but I thought worth asking if you had a parts list? Can I ask why you populated C10 and C11 on the modules as they were empty from factory? thanks, Jason
    I see you already have experience with repair of this amplifier. I need a replacement transistor 102433 with Red logo for Bose 1800. I seek to avoid replacing all 14 devices with new. Do you have any that you could let me have, please? Good used parts will be fine!

    Thanks, Steve
    Thierry
    Thierry
    Hi Steve, Un fortunately I don't have any of these left. Did you try eBay ?
    Thierry
    Hi Thierry,
    Tomorrow, my speaker will be ready. I have another one of these speakers(A723),which is not working and it doesn't have the drivers. I can give it for fixing, but what can I use in place of these three drivers? Do you recommend doing it?
    Thanks
    Hi Thierry, I did download a hifi engine 40 page pdf, that says it is the service manual, but desnt really list all the capacitors or resistors or transistors, etc...
    Is what you have have those details?
    Else I may purchase it from ebay?
    Best, Henk
    Hello Thierry, I was reading your message on the AR Model R; I have one where the output voltage R = 1volt, L = .4volt. So it looks like I have to replace the amplifier components.
    Would appreciate your Service Manual for this and any suggestions you may have, in your own experience.

    Thanks

    Henk Portier 781-449-9990
    Data Recovery, Inc.
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