Starting a Magnavox 196-10 Rebuild

Starting a Magnavox 196-10 Rebuild

I picked up this Magnavox 196-10 (and the little Shure M60) from a good friend the other day. He had picked up the very beat up old console at an estate sale and wanted the speakers to restore some of the other consoles he owned.

I had previously restored a little maggie 8608 as well as an 8802. I traded the little 8608 for an AR-XB turntable, but miss that unique single ended sound signature.

Well, the 196-10 seems like a great little amp to get myself back into the single-ended sound, with its beefy OPT's (for Magnavox, anyway) and its robust power supply. I then heard that this little amp drives the 6BQ5's at 14 WPC! Can this be true? Apparently, they are biased extremely hot. Jim McShane suggests taming them down a bit to get the power tubes to last longer. I would have to agree.

Initially, I wasn't pleased with the rather compact chassis of this amp, which did not produce a layout as aesthetically pleasing as the 8600 or the 8802, but after seeing what some folks here on the forum have done with the little amp, I decided to do a full restore and add the little niceties like wood sides, power switch, etc. and maybe even a custom cage.



I will be redoing this as a "boutique amp" with all very good quality parts. I figure since there is such a low count of caps and resistors in this thing, why not go top shelf on quality (not overboard, just good quality) and give this great little maggie a new lease on life. :yes:

Oh, and the Shure M60 is a phono signal extender. I mainly purchased it to see if I could get a little gain in between my turntable and the Fisher 800B. It also has a nice little Telefunken 12AX7, which I am sure is still in pristine shape. There is not a spec of rust on the brightly chromed little chassis, and the thing looks brand new.

Got the cosmetics done

Ordered a complete set of replacement caps and resistors from Jim McShane, along with a few design changes that he recommended.

In the meantime, I removed the molex connector and everything else I planned to replace. Then I prettied it up with a coat of primer and hammer-tone copper paint. Also removed the can cap and replaced with a little cover. Painted the transformer a nice black and added some little shiny acorn nuts and new stainless bolts to hond it to the chassis.

On the back are your standard 5 way binding posts and a pair of good quality rca input jacks - you'll notice that I just painted over the old ones - better than removing them and leaving a big hole in the chassis.



The wood surround is just cheap $2 birch (I think) from Home Depot.





I'd like to find something to cover those homely OPT's, but it is just a humble little console amp - don't want it to get an attitude.

Now that I've slapped the lipstick on the pig, I need to work underneath to make it sound good. That will make me decide whether or not to invest any more time on it.

For simple covers to fit over the OPT, try either the container store or a store like hobby lobby. They often have stainless steel paint cans of various sizes. The smallest of which can be painted and used as nice little covers.

Depending on the size of the transformer cores, the end bells that Edcor sells (http://www.edcorusa.com/c/113/end-bells) may fit. I successfully used two pair to cover the transformers on a 9304 amplifier. Don't forget to either use shoulder washers or fiber washers and heat shrink tubing on the screws (4-40) to keep from grounding to the laminates.

-D

Thanks for the suggestions on the OPT covers, but these darn things are so close together, I don't think there will be any room to pretty them up. I'll rethink it after I finish the rebuild underneath.

A single 6BQ5 is good for about 5-7 watts output so your 14 watts would be the total of both channels.

I have the same little amp. For a short period of time I used it as a a computer speaker amplifier. Stopped using it as I have not recapped it and got nervous. Sounded pretty good, but I figured it could be better with new caps and possible changes. Look forward to hearing your opinion about your results with the upgrades. Thanks!

Magnavox 196-10 Finished

Finished rebuilding the amp last night - ran it up on the variac for a little while and then checked my voltages.
Listening to Stolen Moments by Oliver Nelson on the little 196-10 right now - this amp sounds terrific!! I am very impressed with the amount of gain I am getting out of this little amp on my Monitor Audio Silver 5's which are not that efficient at 89db 1w/1m.

Here's what's changed:
5 way speaker binding posts
inline fuse
new power cord
3 47uf 450 v Nichicon electrolytic caps to replace the can cap
.01uf 1600v cap to replace the original ceramic
Pilot light socket removed from circuit



470pf silver mica caps replaced the original ceramics
Dale 6.8k metal film resistors to replace the original carbon comps

Also split the cathode bias cap in the can into individual 47uf 50v Nichicons with
180ohm 3.75w wirewounds per channel. Each tie back to the wiper on the hum pot.



On the signal side,
.01pf Russian paper-in-oil 630v coupling caps
Dale premium metal film resistors for the signal path
Standard metal film resistors for power
New phono jacks (originals are bypassed)
Also bypassed the balance pot



196-10 Original Component Values---Replacement Component Values


C1a--40mfd Electrolytic 450v===>47 uf 450 volt Nichicon radial 105C
C1b--30mfd Electrolytic 450v===>47 uf 450 volt Nichicon radial 105C
C1c--10mfd Electrolytic 450v===>47 uf 450 volt Nichicon radial 105C
C1d--20mfd Electrolytic 25v====>47 uf 50 volt Nichicon axial (x2 - one for each channel)
C2---.01mfd Poly 400v===>K40 PIO 630v
C3---470mmf Ceramic===>470 pf silver mica
C4---.01mfd Poly 400v===>K40 PIO 630v
C5---470mmf Ceramic===>470 pf silver mica
C6---10000mmf Ceramic 1400v===>.01 uf 1600 volt snubber rated cap

R1---1meg Balance pot ===>Replace w 1 475K PMF per channel
R2---1k ohm Hum Balance pot===>Clean well & reuse existing pot
R3---100k ohm Carbon Comp===>(remove with bal. pot)
R4---47k ohm Carbon Comp===>.5 watt 1K carbon comp
R5---220k ohm Carbon Comp===>.5 watt 221K PMF
R6---1.5k ohm Carbon Comp===>.5 watt CF
R7---470k ohm Carbon Comp===>.5 watt CF
R8---4.7k ohm Carbon Comp===>.5 watt CF
R9---6.8k ohm Carbon Comp===>.5 watt 6.81K PMF
R10--100k ohm Carbon Comp===>(remove with bal. pot)
R11--47k ohm Carbon Comp===>.5 watt 1K carbon comp
R12--220k ohm Carbon Comp===>.5 watt 221K PMF
R13--1.5k ohm Carbon Comp===>.5 watt CF
R14--470k ohm Carbon Comp===>.5 watt CF
R15--4.7k ohm Carbon Comp===>.5 watt CF
R16*--56 ohm Carbon Comp 2W===>180 Ohm 3.75 watt WW (x2 - 1 per channel)
R17--6.8k ohm Carbon Comp===>.5 watt 6.81K PMF
R18--3.3k ohm Carbon Comp===>100K PMF 1 watt

V2 & V3 6bq5===>6P14P-EB Matched Pair

MF=metal film
PMF=premium metal film
CF=carbon film
WW=wirewound

** On C1d and R16 - I separated the channels and used the values listed. If you keep them together, use the original 56ohm value.

I bought all the caps and resistors and tubes from Jim McShane - he does a great job matching the tubes and provides top quality components. I had previously refurbed my Fisher 800B with one of his kits and was very satisfied with the quality of the components and the recommendations he made.

wweigle said:

I have the same little amp. For a short period of time I used it as a a computer speaker amplifier. Stopped using it as I have not recapped it and got nervous. Sounded pretty good, but I figured it could be better with new caps and possible changes. Look forward to hearing your opinion about your results with the upgrades. Thanks!

Click to expand...

This is the best sounding magnavox amp I have restored so far - I strongly recommend refurbishing it - it is well worth it. To date, I have refurbished this 196-10, an 8608 single ended, and an 8802 6v6 push pull.

In the system...

Here's the little 196-10 in my system. I mainly stream MOG via Sonos (behind the amp) through the Emotiva XDA-2 DAC.

I've to got to find me a pair of >97db efficient speakers to mate with this little amp. The Monitor Audios sound terrific, but I can detect a little distortion at my preferred listening level. The resolution is terrific though! As the amp breaks in, the sound becomes more and more detailed.

Next up, rolling a pristine Telefunken 12AX7 in place of the original Magnavox branded pre tube.

You do fantastic work. You really went above and beyond in the description of your upgrades. Very much appreciated. Looks like I need to start planning Thanks again!!!!!!

Looks great. I have a console with an 8802, I love the way it sounds but don't use it often because it has the original caps. I'm deathly afraid of attempting replacement of them. Can I ship it to Texas? LOL.

69chargerse said:

Looks great. I have a console with an 8802, I love the way it sounds but don't use it often because it has the original caps. I'm deathly afraid of attempting replacement of them. Can I ship it to Texas? LOL.

Click to expand...

The 8802 was the easiest amp to refurbish. There is plenty of real estate under that chassis! A complete recap and resistor replacement along with some fancy new power tubes really spruced mine up.



Seriously, if you can wield a soldering iron without burning yourself, you can replace the caps and resistors in the 8802, especially if you are leaving it in the console - it would just be a matter of a one-for-one replacement of parts. The only area you would have to get a little creative is when replacing the can cap - I don't know if the original spec is still available, but replacing it with individual electrolytic caps or even get Hayseed Hamfest to custom make a can cap to match your original.

wweigle said:

You do fantastic work. You really went above and beyond in the description of your upgrades. Very much appreciated. Looks like I need to start planning Thanks again!!!!!!

Click to expand...

Thanks! Breathing new life into these humble little Magnavox amps is a rewarding experience.

Ak'ers certainly love beating that dead cat back to life,
I hope it serves you well for many years to come. Cheers

Individual Bias Modification

I was asked how I wired the separate bias mod on the 6Bq5's so here's a quick diagram of the new arrangement:



Here's a photo showing the terminal strip with the dual cap/resistor combination. Both are grounded to the center post of the terminal strip with leads going to the center tap of the hum pot and back to pin 3 of the power tubes.

Hi
I picked up a magnavox console(free) with the 196-10 and want to rebuild it but i'm going to use it in the console(it's in good shape).Should I go to the extent you did or keep it stock?
Much thanks
Estev

Estev said:

Hi
I picked up a magnavox console(free) with the 196-10 and want to rebuild it but i'm going to use it in the console(it's in good shape).Should I go to the extent you did or keep it stock?
Much thanks
Estev

Click to expand...

If you are going to keep it in the console, you should just replace all of the capacitors (with the exception of any ceramics.) You could also replace the resistors as well - it's not that much more difficult or expensive and will definitely also restore the sound back to original. Other than that, I would keep it original.

Thanks. In replacing the caps, keep with the same values?

Yes, if you are going back into the console, you should keep the same values. You can use the list I posted earlier in this thread, but keep the caps/resistors from the hum and balance pots. Deviating a little on the electrolytic caps like I did is fine - that's the parts recommended to be from Jim McShane - he knows his stuff. Also, you should check with him for the components - he supplies quality stuff.