That amplifier was not a three channel tube amp. It was set up as a bi-amplified stereo amplifier. There are two single ended OT underneath for the treble amplifiers, and two push-pull OT on top for the lower frequencies. The box that you pulled off from the top was responsible for separating frequencies on each stereo channel and diverting signal to the correct amp and channel. In original configuration each amplifier in each channel was responsible for powering either a horn tweeter or an AlNiCo woofer. Before you tore it apart, that WAS quite a rare and valuable amp. FYI. In any case, I’m glad to see another Maggie back in service.
@@travisvodden6845 These amplifies are being sold mostly on ebay, the restored examples can bring in quite a bit of money. Even the unrestored but functional amps can still fetch several hundred dollars. It is all about knowing what you have and if it works properly. Some of the lesser Maggie or RCA tube amps don't sell for that much.
As you stated this is a bi-amp unit with 2x 6V6s for the high end and 4x 6V6s for the lows. I have not yet found a schematic online. It looks like you have set yours up just as a full range stereo amp and eliminating two of the output tubes. The pictures I've seen of an unmodified unit online are not great, but it looks like the speaker outs are via one of the Molex connectors. There appear to be output screw terminals for one channel (?) with "H-C-L" (high-common-low?). Are the two smaller stand-alone transformers high frequency speaker outputs, and the low end channels through the big black transformer? Do you know the crossover frequency originally used? NOTE that I am not referring to the unit in this video - it has been changed from the original design. I am referring to the original 1960 bi-amped console amplifier.
Hey Shaun, the power amp sections have 6V6 tubes . . Not 6L6. The high frequencies are handled by a single ended 6V6, while the lower frequencies have a push pull configuration. This means there are 6 total output tubes, and 4 output transformers. The large transformer provides power for the filaments and the high voltage needed to run the amp. There are many resources online to help guide you through vacuum tube electronics theory if you want to learn more.
I think that vintage amps sound so much better then the new amps of today . they really make you feel every sound and breath and makes you feel like you are in the recording studio as it is being recorded . Magnavox really made great gear and it is too bad that companies of today do not take pride in what they are doing . in my opinion vintage gear is the best . thank you for posting this and I look forward to more videos happy july 4th
This was originally a bi-amp unit with 2x 6V6s for the high end and 4x 6L6s for the lows. I have not yet found a schematic online. It looks like you have set yours up just as a full range stereo amp and eliminating two of the output tubes. The pictures I've seen online are not great but it looks like the speaker outs are via one of the Molex connectors. You are clearly a way more knowledgable tube tech than I am but I would be curious as to your thoughts on restoring one as a bi-amped unit. There appear to be output screw terminals for one channel (?) with "H-C-L" (high-common-low?). The original unit had two output transformers on the inside and two on top for the four speaker outs (L-R high, L-R low). Anyway, nice work! I'm a lifetime sound engineer for live and film/TV postproduction but I am now getting my feet wet with some restorations of old gear I have owned for years (just finished the Fisher KX-200 I got in 1974 and it came out great and sounds amazing!)
Thank you for your video. I have a Magnavox 9302 that had been restored by someone else. Looking at the bottom of mine it has the electrolytic capacitors replaced and a fuse added but the original death cap is still installed. I will replace that and add in a cl-80 thermistor. Thank you again
Man years ago I found a medalist in the monroe louisiana dump( early 90's) I salvaged the power amp and the pre amps( discreet) sections. It was my boss that already saw it many times just sittin rotting on the way into the dump. He's the one that told me, " Hadley you oughta get that amp" So one day while we were there they dropped me off with some pliers while they dumped. Needless to say years later bout ( 6) i built a boutique head. Looked good. Black vinyl white tweed gold backplate neon light ,toggle switches, Tried to make it look like a marshall. Put three jacks for the input. Left both and right. The both was a switching jack.
I am not a fan of the old can caps, as I would have replaced it with poly's if you have enough room underneath, and I would have placed some really good foil coupling caps in the signal path before the output stage. I would have replaced the power cord, with the 3-prong with a IEC filter and you can use after market hi end power cords with it! I would have used the parallel 5u4gb rectifiers together. That's all I would do, and built a really nice wood casing around it! This is just my 2-cents worth. Also could not hurt to replace the existing choke in the PSU, with a higher Henry rating. I do like the fact you took out the tone circuit, and took out the center channel! Not needed.... Good job!
It was not a "center channel", it was a "bi-amped" system. Two bass channels and two treble channels.. Center channels were used when RCA had "Living Stereo" reel to reel tapes before records were released in stereo. I think only RCA and Motorola did center channels on their amps..
This is a 4 channel amp. 2 bass channels running in push-pull with 2 output transformers on the top of the chassis, and 2 treble channels running in single-ended with 2 output transformers inside the chassis. You can see all 4 output transformers in the video. This is a great amp for bi-amping. Why did you remove the two treble channels?
Basically it has been ruined, not "restored".. It would have been so nice to hook it up to some special bookshelf speakers and wire the bass and treble separately..
What a waste removing the HF Amp and making it a fullrange stereo amp. In its original form 2 LF amps and 2 HF amps crossed over @ 1200hz it can be an excellent amp for driving an Altec A7 system.
I just discovered your channel and am happy to subscribe, looking firward to seeing more great restoration videos. But I am wuite surprised you didn’t notice the configuration As a bi-amped stereo unit instead of seeing a center channel. I should think a fairly cursory examination of the circuit (let alone a Sams) would have given you a clue (eg. How many output transformers does it have?). Interesting hobby you have!
I tried to go to your www.blueglow.net site but got this message: This site can’t be reached Not sure what the deal is with it. I was glad to hear you mention what you did about making a secure connection with the wire and not depending on the solder to hold things together. I have a particular "irk" about that habit of many people. I prefer the N.A.S.A. method, which is pretty much what you said to do. I am curious. Since you made all those holes to provide the mounting for the banana jacks and the RCA style connectors...and I think the fuse holder as well... WHY did you put the power switch so far away from the entrance of the power cable? There looked to be ample room to install the switch near the fuse holder and would have saved running so much wire carrying the AC around the other components. True you kept it away from the most important area, but I am just curious why you chose to do it the way you did. When you mentioned that the original configuration was with 3 channels, I thought it would be great to use one for a "Sub Woofer" source...but I guess the owner either didn't have a sub woofer, didn't want a sub woofer, or something like that. When you mentioned that you took out one of the rectifier tubes I winced...thinking it was so cool the way they had done that...but once you mentioned the excess power drain, it made more sense to me. There is a video I wanted to share with you ...I think you will enjoy it. Hope so anyway: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BnR_DLd1PDI.html Thanks for uploading your video!
Before stereo records, there were pre-recorded stereo tapes that had a "left-right and center", but that was primarily RCA "living stereo".. This amp actually has two bass channels and 2 treble channels, which was very nice for early stereo.
Is there not an issue regarding compliance with modern electrical safety regs if using cloth covered cable? Or would it just be illegal to use it in a brand new amp but ok in a unit that came fitted with such wiring from the factory & therefore the work is classed as repair / modification & not construction? I'm not familiar with the regs for (what I assume would be for) portable appliances & am curious how / if they would apply to seemingly antiquated components like cloth covered cables? Loving you videos by the way; very interesting - just one thing (that ISN'T meant as a criticism by any stretch) that i notice on all videos lol this: whenever any power tools are used, they are always really loud compared to the dialogue. This must annoy headphone users. I wouldn't know how, but if the overall max Vol level could be limited to that of the loudest dialogue, it'd make for a much more pleasant viewing. Doesn't detract from the thumbs up 👍 for all your vids on vintage hifi though....kind regards
