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Thread: Baldwin Orgasonic 54a buzzing

  1. #1


    Baldwin Orgasonic 54a buzzing

    Hi, i purchased a Baldwin Orgasonic 54a yesterday and when i brought it home, everything worked. However, the panoramic setting had a loud buzz. Today i woke up and turned it on, and now the organ has a constant loud buzzing no matter what i do. I took off the back to take a look inside to see if there was anything noticeably wrong(although i dont know much about these things). Some of the tubes get very hot(i dont know if this is a problem). The buzzing seems to be coming mostly from the speaker on the left(if youre looking into the back of the organ). When i turn the amplifier gain down, the buzzing seems to subside but there is no volume. I really love this organ and any help on this matter would be greatly appreciated. Thanks.

  2. #2


    Re: Baldwin Orgasonic 54a buzzing



    The tubes will get hot (esp the power and rectifier tubes) but you want to be sure that you are not getting red plating (more on that later). Does the buzz sound like about 120Hz? Most likely the power supply caps are shot by now which would cause a loud buzz or hum. It sounds like the problem may be in the amplifier rather than the tone generators (let's hope so).</p>

    If you want to use this organ I strongly suggest replacing all of the electrolytic and paper or wax capacitors in the amp section. Definitely want to replace the power supply caps and any caps connecting the plate of one tube to the grid of the next. When (not if) these fail they will usually cause rather significant damage. Ceramic and Mica caps can usually be left alone. Any resistor from the grid of a tube to ground should be checked against its marked value and replaced if out of spec (especially if more than 10% high).</p>

    With knowledge this maintenance can be done without a schematic or service manual but in my opinion it is worth it to get them even if you have to buy them. Here is a useful site for you.</p>

    http://frank.pocnet.net/</p>

    This site is great for downloading data sheets for nearly every tube known to man. These sheets have a lot of useful information including the pin out diagram of the tube (as viewed from below). Tube type will be printed on the glass envelope somewhere as a rule. Not sure of the tube compliment in that organ but you will be looking for numbers like 12AX7, 12AU7, 6SN7, 6SL7, 6L6, 6V6, 6BQ5, EL84, EL34 etc.</p>

    http://media.photobucket.com/image/tube%20red%20plating/AC50/AC100/tubes.jpg</p>

    This pic of four tubes shows normal operation except for the second tube from the left which is red plating. You see that all of the tubes have a glow in the center from the heater that heats the cathode. On the red plating tube the outer electrode called either the plate or anode is glowing red. This indicates that it is dissipating way too much power. This is usually caused by bias that is off due to mis-adjustment or out of spec/failed parts such as caps and resistors. Many tubes have another electrode called a screen between the plate and cathode which also should not be glowing. Sometimes the screen is hard to see unless the plate is designed with holes in it. The screen can pull to much power just like the plate for similar reasons, that is failed components in the screen circuit.</p>

    Replacing the suspect parts is really not as scary as it sounds if you can handle a soldering iron. The folks over at the AudioKarma tube forum can provide some very knowledgeable guidance if you want to give it a whirl.</p>

    If you can post some pics of the amplifier it will help identify what you have. Also note that somewhere in the back there should be a tube map showing what tubes are used and where they go. If you can post a pic of that also it would help.</p>

    mike</p>
    If it is Caesar that you worship, then Caesar you shall serve.

  3. #3


    Re: Baldwin Orgasonic 54a buzzing



    thank you so much for the informative reply and all the help. Like i said, i dont know much about these thing but i hope these pictures are helpful. thanks again!</p>

    </p>

    <span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; ">http://img24.imageshack.us/i/1115091829.jpg/</span></p>

    <span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; ">http://img38.imageshack.us/i/1115091829a.jpg/</span></p>

    <span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; ">http://img69.imageshack.us/i/1115091830.jpg/</span></p>

    <span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; "><span class="Apple-style-span" style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 13px; white-space: normal; "><span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; ">http://img195.imageshack.us/i/1115091830a.jpg/</span></span></span></p>

    <span class="Apple-style-span" style="font-family: Arial; font-size: 10px; color: rgb(51, 102, 153); white-space: pre; ">http://img36.imageshack.us/i/1115091830b.jpg/</span></p>

  4. #4


    Re: Baldwin Orgasonic 54a buzzing



    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">&lt;a target='_blank' title='ImageShack - Image And Video Hosting' href='http://img24.imageshack.us/i/1115091829.jpg/'&gt;&lt;img src='http://img24.imageshack.us/img24/5197/1115091829.jpg' border='0'/&gt;&lt;/a&gt;</span></p>

    </p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">&lt;a target='_blank' title='ImageShack - Image And Video Hosting' href='http://img38.imageshack.us/i/1115091829a.jpg/'&gt;&lt;img src='http://img38.imageshack.us/img38/3319/1115091829a.jpg' border='0'/&gt;&lt;/a&gt;</span></p>

    </p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">&lt;a target='_blank' title='ImageShack - Image And Video Hosting' href='http://img69.imageshack.us/i/1115091830.jpg/'&gt;&lt;img src='http://img69.imageshack.us/img69/3823/1115091830.jpg' border='0'/&gt;&lt;/a&gt;</span></p>

    </p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">&lt;a target='_blank' title='ImageShack - Image And Video Hosting' href='http://img195.imageshack.us/i/1115091830a.jpg/'&gt;&lt;img src='http://img195.imageshack.us/img195/8985/1115091830a.jpg' border='0'/&gt;&lt;/a&gt;</span></p>

    </p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">&lt;a target='_blank' title='ImageShack - Image And Video Hosting' href='http://img36.imageshack.us/i/1115091830b.jpg/'&gt;&lt;img src='http://img36.imageshack.us/img36/3553/1115091830b.jpg' border='0'/&gt;&lt;/a&gt;</span></p>

  5. #5


    Re: Baldwin Orgasonic 54a buzzing



    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">http://yfrog.com/121115091830bj</span></p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">http://yfrog.com/131115091829j</span></p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">http://yfrog.com/121115091829aej</span></p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">http://yfrog.com/121115091830j</span></p>

    <span class="Apple-style-span" style="font-size: 12px; line-height: 16px; white-space: pre; ">http://yfrog.com/5d1115091830aj</span></p>

    </p>

    sorry about that. had a little trouble uploading the pictures</p>

  6. #6


    Re: Baldwin Orgasonic 54a buzzing

    and also, to add.. it is a bit more of a humming noise thatsoccurring. the panoramic setting is much more of a staticy buzz.

  7. #7


    Re: Baldwin Orgasonic 54a buzzing



    OK. The last picture is where the action is.</p>

    </p>

    Lets attack the hum first as that is the most critical issue IMO. The picture is too blurry to read anything on the chassis (no flash?) but here is what I can tell and/or guess.</p>

    Power transformer is in the back right next to the fuse holder. The big tube to its left in the back must be the rectifier which changes AC output from the tranny to DC. Looks like it might be a 5U4 by the looks of things. In any case as long as it is not showing signs of distress (pyrotechnics) it is probably OK. The metal cans and the cardboard one should be capacitors. I am not sure what the one on the left is for but the two in front of the PT are probably the power supply filter caps. You will be removing the chassis and at that point we can look underneath and confirm/draw out the circuit to be sure.</p>

    First a standard disclaimer. This is a tube amp with very high voltages. The voltage supplied to the plates on the tubes is probably on the order of 300V. The AC voltage on the power transformer will be on the order of 700 to 800V. If you are careless this could cause an early appointment at the pearly gates. No need to be fearful but definitely be cautious. Never put any part of your body inside the chassis when powered up. Use clip leads for all voltage measurements. To take a reading be sure power is disconnected. Make sure large caps are discharged. Connect leads to points to be measured. Triple check that nothing is shorted out by the test leads. Apply power being ready to kill power immediately if necessary. Note the reading. Disconnect power and discharge caps as needed.</p>

    With power disconnected mark all wires that are connected to the chassis with tags made out of masking tape. On any multi-pin connectors I like to put a dab of silver paint on the plug and socket to make it easy to see proper orientation. Disconnect all wires. Use masking tape to mark each tube and socket with an identification number (1 2 3 etc) so that you can get the exact tubes back in the exact sockets from which they came. Gently remove the tubes by pulling up with a slight rocking motion. You can use a rag or chamois if you like to be on the safe side. Now unscrew the chassis and carefully remove being careful not to get your fingers under the chassis in case the caps have a charge. Arrange the chassis on your bench in a way that is stable and won't break anything and allows you access to the underside. It would be nice to take a good picture of the underside and post it here but you should find a wire coming from the rectifier to one of the can caps.</p>

    Safest way to discharge the caps is to make a discharge tool using say a 51k or so resistor with insulated clip wires on both ends. Clip one end to the chassis and the other end to the cap terminal (+) to be discharged. That being said it is quite possible that the caps will be mostly discharged already and yo can check carefully with your meter.</p>

    Now here is what you will see on the bottom of those caps. Each can will probably have at least three terminals. One will be connected to the chassis by a big bunch of solder looking kind of like the Mississippi delta. The others will be connected to various parts of the circuit. These caps will need to be replaced. There are three ways of doing this. 1) the expensive way that is completely original. 2) the cheap way that is difficult but looks original 3) the cheap and easy way.</p>

    1) Find an exact or nearly exact replacement and put it in after finding some way to get enough heat to get the solder off of the ground lug.</p>

    2) Remove the can with this mega heat source, cut it open and stuff it with modern caps and glue it back together.</p>

    3) Cut the leads to the original and mount modern caps underneath the chassis out of sight.</p>

    I you can get a schematic it will make it easier to identify the cap values and how they are wired. If not many (most?) can caps have a legend embossed on the side of the can showing the values (e.g. 30uf [A.K.A. 30mmf] 450WVDC). There will be a symbol beside each specification which looks like the old fashioned shape notes; square, diamond half moon etc. On the insulator underneath the cap the terminals should be labeled with the corresponding symbol.</p>

    The intent is to get proper caps put in place of the existing ones with the right polarity. So the next step is to get the picture of the underside and if possible get a schematic.</p>

    That should give you enough to get started. If in doubt ask as we don't want to damage you or the amp.</p>

    BTW, it looks to me like the four smaller tubes to the front are small signal tubes such as 12AX7 or 12AU7. The six taller tubes in back look like power tubes like 6BQ5/EL84. I am guessing that you have at least two channels there as it looks like the other to transformers are probably output transformer. The smaller one for high frequency speakers or reverb maybe and maybe the larger for woofers. Looks like a nice amp.</p>

    mike</p>
    If it is Caesar that you worship, then Caesar you shall serve.

  8. #8


    Re: Baldwin Orgasonic 54a buzzing



    Sorry, didn't realize how big the picture was.</p>

    mike</p>
    If it is Caesar that you worship, then Caesar you shall serve.

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