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Magnavox console 6v6 pp console amp


whamo

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Hey all, about a month ago on my way to the post office I seen an old console on the side of the road. So I checked it out and it had a tube amp in it. I've seen these go on e-bay for $60 or so with no tube in them and real shabby looking. I had the day off today so I started messing with it. I don't have a variac so I just went for it since I have nothing invested. I found out how to bypass the switch and such and it works. I hooked up a cheap speaker and the laptop and it doesn't sound too shabby. It consists of 4 6v6's, 2 6eu7's, and a 6ca4. I think I'm gonna put nice phono and speaker jacks on it and keep it. I need to find the schematic too so I can replace the caps and such. I think it's a good score overall for free. I'm gonna try it out in the bedroom with my heresy's next. Let's see if I can post a pic.

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I can find the schematic for the 175XX series from the Yahoo groups Magnavox friends group.

This is 6V6 push-pull as well, but uses a 5U4 rectifier with a little one henrie choke in the power supply, and 12AX7's as driver tubes.

Other than that, the circuit is pretty much the same thing. Check out the quasi-bias scheme with the hum or balance pot tied in with it.

I suppose there is three versions of this circuit. The series like yours, (143XXX?) with the 6CA4/EZ-81 (mmm..mullard) rectifier, with a no choke CRC type power supply, and 6EU7 driver. 6 volt version of 12AX7.

The 175XXX series, with the 5U4 rectifier, and choke PS, with 12AX7 drivers.

Then there is the 9300 series like I have, which is a 6BQ5 push-pull with a 5U4 rectifier with the little one henrie choke, and 6EU7 driver tubes. There may be a 6CA4/EZ-81 rectified, CRC type power supply 6BQ5 version with 12AX7 driver tubes, who knows.....

It would be a easy rebuild, replace the coupling caps and the PS can capacitor. My stock can cap in my 9300 lasted a couple years, but it finally took a dive, so I'll have to find another cap and make another pass through the amp. The 9300 has excellent midrange and highs, but while there is decent bass with decent extension it is a little light.

One of these days I'd like to find some nice high quality 6.6K primary OPT's at about 20 watts. Something with some good inductance for bass, but not at the expense of the good midrange and top-end.

The maggotboxes are good sound for dirt cheap.

Good luck.

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Thanx Mike, I checked out the magnavox friends site. They do some pretty cool stuff over there. I'd like to use some hammertone green on mine like cruisairs (isn't he a forum member here?). Thanx again for the helpful info as google was no help for this one. Mark

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  • 1 month later...

Hey all, well I've been busy working on this magnavox 8802 and I figured I'd post a followup of my progress. I installed a new power switch, IEC powerplug, speakerjacks, coupling caps etc. I was going to paint it but I figured that would be a sin since it shined up so nice. I had a friend make a nice oak frame for it. I got a new 6ca4 and two 6eu7 tubes as well. I also put some nice stainless steel feet on it too. Now all I need to do is bypass the balance control and bypass the 1.5k cathode bias resistors for the driver tubes with 20uf caps. According to a "Friends of Magnavox" forum member this will address the shy bass problems. I think it sounds wonderful and I like it better than my ST70. However my ST70 is strictly stock. I think that will be a up and coming project pretty soon. Anyways it was a lot of fun. I hope I can get a pic to load now. Take care, Mark I also need to figure out what to do about the pilot light either add one or remove the wires.

post-17845-13819321685224_thumb.jpg

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That turned out nice. Good work, Mark.

I need to go through my PP 6BQ5 Magnavox amp again. I already have side panels cut out in red birch to use. I may paint or powder coat the chassis this time......

The Magnavox console amps aren't bad amplifiers with a little TLC. I'd like to hear the 6V6 PP version.

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Sorry my mistake

according to that schematic, it's Push-Pull

I thought I could only see only 2 wires on the primary sides of the output transformers but it was the secondary side, plus it's somewhat "odd" that the coupling caps to each push pull pair are of a different value (.047 vs .0047) which had me thinking SET (still unsure why that's the way it is as it seems to me the PP pair would quite imbalanced)

Sorry

WOT

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That's cool. Thanx. All I know is it sounds like the angels singing. And it it has room for improvement and I didn't spend a whole lot of dough on it so I feel I can experiment and do as I see fit with it. Plus it's relaxing and fun too.

That's definately how it happens... you got it BAD! [:D]

WOT

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