1964 Conn Organ Amp Modified for HIFI Stereo Pt 1 of 2
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- čas přidán 26. 02. 2020
- I purchased a Conn organ from 1964 for $10 at a thrift store in Arizona. I harvested all the vintage electronics and modified the tube amp for stereo use. The original organ was infested with rodents so not restorable.
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You should get boxes for the alnico speakers that were in the organ and use them with the amp. They're full range and are part of the magic of the tube amplifier sound
I did purchase an open back guitar style box and mounted the organ speakers in it. They sound really good but I haven't found an application for them yet. I may use one of them in a 1947 Motorola radio phono combination console that I'm restoring that is missing the original speaker.
I just picked one of these up. My main amp is a voice of music stereo tube amp and I’ve been on tiny for another project. I was a little bummed when I only saw one output transformer and assumed it was mono until I turned it upside down and saw the other one on the bottom of the chassis! I’ve been picking up old organ people can’t get rid of and taking the good parts out. From 2 organs I’ve gotten 70 12ax7 and 12au7 tubes, one mono amp and this dual channel amp! What I usually do with the big capacitor cans is leave them where they are unhooked and just hide the replacement caps under he chassis so it still looks original and you don’t have to cover the holes.
I usually leave the can caps installed and hide replacements also. Since some of them broke in transit and I needed mounting holes anyway, I decided to remove them all. Good luck, that amp makes a nice stereo hifi amp. Let me know if you need the schematic.
A schematic would actually be very helpful.
Send me an email to mguessva@gmail.com and I'll forward the schematic to you.
I just scored a Wurlitzer 7045 tube amp already removed from the organ for free and the spinning speakers that’s came with it
Good find. What's your plan for the amp and speakers?
@@mguess I always wanted to build a tube amp because I remember what they sounded like at my grandparents and dads growing up in the 70s and 80s. Also my father was working on one he didn’t get to fines before he died and it always fascinated me. I consume all kinds of music all day and really want to build one for playing music. On the other side we are quite poor lol and my 14 year old daughter wants an electric guitar so I may build an amp. So I guess the answer is I’m not sure. I like that it’s kind of plug and play which helps me because I’m not that circuit literate yet.
Get a regular preamp you will enjoy it much more
Thanks for the comments. I have already followed your advice and added a Mcintosh C28 preamp about a year ago.
I have a mint 1965 conn like this one. I'm a guitar player. I'm twitching to convert this to an ultra cool stereo guitar head. I made an amp from a kit and read a few books, but I'm not convinced I could pull off a conversion. Some day!
It shouldn't be too much work to make a guitar amp with the Conn organ amp. It makes a great stereo hifi amp. I have the schematic diagram if you need it. Uncle Doug and D-Lab do a lot of guitar amp service and conversion videos.
Very helpful information. Thanks a lot
I'm glad the video was useful for you.
I have a dual amp treble & bass found in Hammond’s earlier models. Treble is type JR 1A and bass is type K. This unit came with a reverb tank.
I was wondering if it was possible or rather worth converting these to a stereo amp. I mean they look pretty dang cool.
I'm not really familiar with the Hammond amps. You would probably need to find a schematic for the amp to see if you can modify it for stereo. The Conn amp was fairly easy to modify.
@@mguess I have a schematic. It actually came out of an old Tone Cabinet Model H-40. I am just getting into this stuff. I converted a Magnavox 9302 amp. This one seems a little intimidating. Do you do custom work?
I'd be glad to help as much as I can. Would you be able to forward the schematic to me at mguessva@gmail.com.
Wow, what a find! And the rejuvination of the amp turned out great. There is no substitute for that warm tube sound, that's for sure. And I commend you on your choice of bookshelf speakers---I'm a big Klipsch fan
Thanks for the comments. I love the sound of that amp. I now have it connect to a pair of Advent Legacy speakers from the late 80's. The small Klipsch speakers are my workbench speakers currently connected to my 1965 vintage Harmon Kardon FM receiver.
Please share where you purchased your Conn's owner's manual. I was given a Conn Deluxe Caprice-465, and I'm having little luck locating a manual for the device.
Thanks in advance
Best,
I believe that I purchased the service manual on eBay. There is one currently listed on eBay for the model 465 for about $20. I think that's about what I paid for mine. Worth it, even though I only paid $10 for the organ.
Did you say you are Virginia? If so what parts? I currently live close to Fredericksburg.
Yep, Fairfax County.
@@mguess Oh wow I’m in Caroline. We moved here a couple years ago and bought our first house. We have family and grew up in all of nova. We are in Fairfax alot to see my wife’s mom.
So you didnt USE the power tranny and the rectifier tube?
How did you power the two amps?
Thanks for the questions. The power transformer is being used. The amplifier chassis uses solid state silicon rectifiers to provide the high voltage DC for the amplifier section of the circuit. This part of the power supply uses a voltage doubler circuit to provide up to 450V DC. There are two extra tubes (0A3 and 6DN7) which provided regulated DC voltages to other sections of the organ which are no longer present, ie tone generators. I have used the amp without these tubes installed and it works fine. I usually leave them installed because the 0A3 voltage regulator tube gives off a nice glow which I use as a pilot light to let me know the amp is powered up.
@@mguess ok thanks-
Im understanding more and more here.
So you added silicon diode rectifiers in addition to the 'taps' off the tubes.
Im a guitar player, and ive been collecting these old salvage projects for 50 years, and ive just finally settled into a new place, so im beginning to sift through them to build some guitar amplifiers.
I have several like this so i have to determine whats best to keep and how to build a separate amp from the 2nd half.
Its so exciting when these amps come to life.
Hi Ed. I didn't add the silicon rectifiers. They are part of the original 1964 vintage organ amp. I'm still using them unmodified. This circuit doesn't use a tube rectifier like most guitar amps of the 60's vintage. I think solid state rectifiers were just becoming available and reasonably priced. I think it probably made it easier to implement the voltage doubler circuit which required 3 diodes. It also may have saved a bit on the power transformer but I'm just speculating on that. Good luck with your tube amp projects. They definitely have a cool vintage sound which is hard to duplicate with transistors.
Understood the organ tube amps were designed for instrument music only. Do you think they have narrow frequency response than audio tube amps?
Thanks for the comments and good question. There were some capacitors in the output stage of one channel and the negative feedback loop of the other channel. I believe these were there to alter the frequency response of both channels for the organ. I just removed the capacitors as part of the conversion to a stereo amp. After the conversion I performed a frequency sweep of both channels and determined that they have a fairly flat response from 20 Hz to 20 KHz.
if you put a stereo preamp between the turntable and the power amp you'll get the most out of that thing ...you probably are aware of course
You are correct and I recently did just that. Check out a recent video on my current system configuration. czcams.com/video/77wais1rl-I/video.html
@@mguess i have this very amp and it just developed a hum which i KNOW are filter caps..150 uf at 300 volts is a wierd value for power caps and its hard to find ...im trying to see wht you used and how u applied it
I used electrolytic capacitors rated at 450 volts. These are easy to find. You can always go higher in voltage ratings but not lower. Good luck with your project and let me know how it turns out.
@@mguess cool ty its a lil wierd arrangement on the original power supply but ill work it ,,,,i believe the 150 /300 volt cap is the culprit as its carboard and bulging on the top
@@steveeolio The power supply in the old Conn amp is a voltage doubler design which is why it can produce 420 volts with capacitors rated at 300 volts. If you are still using all the original electrolytic capacitors you may want to replace all of them. I have the schematic for the amp if you need it.
great video. any chance you might share that schematic?
Sure. If you want to forward me your email address I'll send them your way.
@@mguess just my username @gmail.com
I'll jump on this too; I have the same amp at home and it's due for a refurbish if you have the schematic electrically available. Thanks!
I have this exact amp hope you are still active on here .May i also have a copy of this schematic
@mguess - I have the same amp and would love to have a look at that schematic - Would you be willing to share a copy of it? Mine like yours looks like it had low hours. I still have a pair of the Conn house labeled 7868 - I sold the other pair to a gentleman that was repairing an Ampeg guitar amp. Plan to use mine for a Stereo bench amp to drive a pair vintage Advent speakers. I plan to use the EH7868 for replacements or rewire with octal sockets for use with 7591. These are cathode biased output stages, so I may re-bias for use with 6L6GB/5881.
I'd be happy to email you the schematic if you could forward me your email address.
I just came across you video about a “Conn Organ Amp Modified for HIFI Stereo”. By coincidence, on February 25, 2020, (which is just 2 days before you posted your You Tube video) I brought home a Conn Rhapsody, Model 627 organ from my aunt that passed away. I removed the tube amp, Leslie speaker, the 2 dozen 12AU7A tubes, and a few other goodies. I, too, intend to use this amp as a stereo amp and use the Leslie speaker for my guitar. Your video(s) are very good and I have watched them several times. May I correspond with you by e-mail for more detail? I have a g-mail account and my user name is dwlum51. (I also retired in 2013 as your home page stated about you.) I already purchased the Conn service manual for this organ.
I'll send you an email. Good luck with the amp and leslie conversions.
What's the best organs to get Amos from. There are always people giving them away where I live! Thanks for the video on my Infinity 3007s. Turned out badass ! Do one on the old 7kappas please! Hahahahaha
I'm not that familiar with organ amplifiers, the Conn in the video was the first one the I have worked on. However I would probably pick up any organ with a tube amp if it was cheap enough. Luckily for me the Conn amp was easily converted to stereo use which is what I wanted. I'm glad your Infinity speaker restoration was successful. The are great sounding speakers!