Yes, an eBay find, I am wondering if anyone knows much about this little guy?

I intend to use it with my Visaton b200 open baffle speakers, and my Slimdevices SB3 computer front end.

I believe it runs 4-7 wpc, tube rectified etc.

Anyone familiar with it etc?

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ih=007&item=170020494714&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1

I was going to offer the schematic, but I see it comes with one... this was built around 1960 (that's the date on my schematic).

7 watts is VERY optomistic - 2-3 watts per channel is more like it. Should be fine with open baffle speakers, depending on the listening level you want. I use similar amps with my computers at work and home.

Thanks for the reply Tom, I have 96Db speakers, so I would think that for my listening levels, especially leveraging a subwoofer, to do the heavy bass lifting, I should be OK.

This is the first time I have ever seen 3 binding posts, apparently this uses a common negative ground.

Have a great one!

Hi, I have a similar Magnavox 83 console amp with 2 EL84s, a 6EU7 and an EZ81. I think you are going to be really surpised in how good it sounds. I love mine and use it almost everyday. I beleive that the 6n14n/6P14P is similar to the EL84 so my guess would be more like 3-5 watts. I don't know whether the amp is operated in pentode or triode mode. If triode mode you'll prolly be closer to three watts. I wish I knew whether mine was triode or pentode. Either way you'll need speakers with a high sensitivity. Nice amp you got there, enjoy. Loren

Maybe a little spendy at a 140 bucks, IMO. But, it's a nice amp. They have better bass response compared to the model 83 6EU7/EL-84/EZ-81 type amp.
It should be pentode connected, unless the seller strapped the output tubes in triode.

The model 83 has more extension on the top-end, however. It does have good bass for a teeny little choke looking OPT.

If it was my amp, the ruskie tubes would have to hit the road.....good for a push-pull I suppose, but too raspy for a single-ended amp. (That's the impression I got using the Russian EL-84M's in the little Maggotbox.)

I can survive the otherwise "steep" entry fee, this is my first tube amp ever, and some guys I trust suggested this would be a safe entry, for this experienced Class A SS, or digital amp guy.

Can you recommend some tubes, I am welcome the advice!

I dunno what speakers you are going to run that amp with, OB I think you mention......all things considered, with high efficiency speakers you will probably like the amp and it will be a keeper.
The Magnavox 6BQ5 SE console amps are IMO, a poor man's single-ended triode amp.
Rather close to the SET sound for a lot less cash. They just don't get as loud.

If the amp you won on the listing comes in one piece, has good strong tubes, and is plug and play, then it's worth every dime of that 140 bucks.
It's a good single-ended 6BQ5 amp, with modest sized OPT's, and a choke in the PS. (dunno why it has a 5Y3 rectifier, I thought they had 5U4)
You don't get a CLC PS with the model 83, just CRC with the 6CA4/EZ-81 rectifer.

I am poor. So if was hunting for a Magnavox SE console amp from eBay, I would look for something sans tubes and really dirty. Get it for less money, then rebuild the amp.
I forget some folks don't want to cock around with rebuilding a tube amp, and just rather buy something plug and play.

A local audio friend Dan Marshall has a Magnavox SE 6BQ5 just like yours.
In the last 4 or 5 years I've known him, he has cycled through at least a dozen tube amps of various types and topologies. Some stay, most are gone......but his little SE Maggotbox hasn't gone anywhere.
I'll never get rid of my model 83, it's small and reliable, with good tone.
The 83 mates well with my '83 Cornwalls. It just doesn't get that loud.....it does with a linestage...

A Mullard 12AX7 would work well, a Telefunken 12AX7 would probably do good. A RCA 12AX7, or whatever you can scounge up.
The driver tube that comes with the amp may be fine tonewise as well.
Mullard EL-84's sound good in my SE 6BQ5 amp, I like the Sylvania black plate 6BQ5 a little better I think.....Still smooth, with a little more bite. The GE round-plates are kinda the same way, they are a good sounding 6BQ5. Better than the RCA examples I used. Philips EL-84 are okay, a little shouty in the midrange, depends on the circuit I suppose.
New production EL-84/6BQ5 would be JJ or EI I guess.......I have some older EI EL-84's that sound pretty good in the SE 6BQ5 amp, better than the Russian EL-84M's I tried.
Whatever you can afford.........

The nice thing about this amp is, you can always tune it a bit more, and put better connectors on the chassis etc. so if you get sick of it it'll sell nicely on the 'bay :D

Good points all, thanks for the tube suggestions, I will try to sort them out, once the unit arrives.

Here is a link to some pics of the drivers in question, a german 8 inch full range unit, awesome build quality, and very nice sound.

http://www.audiocircle.com/gallery/thumbnails.php?album=446

Here is a link to some pics of the actual open baffles themselves, in my unfinished basement listening cave!

http://www.audiocircle.com/gallery/thumbnails.php?album=54

I have already had two folks get in touch with me, and ask for dibs, if I want out of the unit, at cost etc, so I am happy to experiment.

I suspect I will like it, but having never owned a tube amp, am not ultimately sure...

I am scoping out better speaker connectors etc, and suspect that I will poke around it a little - but electronics are not my strong suit!

I think I need to start selling my pile of SE console amps off based on that closing price.

Sure, you just need to find 2 idiots like me and the other guy who tried to snipe it last second!

:D

I think I need to start selling my pile of SE console amps off based on that closing price.Let me know when you start.
Sure, you just need to find 2 idiots like me and the other guy who tried to snipe it last second!I'm your huckleberry.

"Here is a link to some pics of the drivers in question, a german 8 inch full range unit, awesome build quality, and very nice sound."

Duh....Visaton...I should have read your first post a little more.....nice drivers.

I've never heard a OB set-up before, it would be interesting to hear.
That little SE amp should sound rather good, never know until you try it.

Does the Slimdevices SB3 have some sort of a volume control?

You are right about the SEP amp, I look forward to exploring the synergy with the OB b200 full rangers.

http://www.slimdevices.com/pi_squeezebox.html

Here is a link to the Slimdevices homepage for the SB3, it sure does have a volume control - I sold off a Nakamichi cd player, external DAC, and tube preamp, once I discovered this jewel. I also had it highly modded by Wayne at Bolder Cables - http://www.boldercables.com/servlet/Detail?no=372 - He has done work for me before on a DAC, and some digital amps also. Great stuff.

The SB3, once connected to your computer, basically replaces a transport, a DAC, and a preamp - since I use only that source, I don't need anything else - just an amp, and speakers.

The unit arrived yesterday, and is functional. Good.

Swapped in some matched 70's EI EL84's, a Tung Sol 12ax7, and a GE 5Y3.

Good sound, not fantastic, not super amazing, but good. Nice mids, decent (if a little wooly) bass, and extended (if a little gritty at times) treble.

I think it will be worth investing a little more in, to update the PS cap, the output caps, and put some real binding posts on.

MORE than enough volume, with my Visaton open baffles, and kept me in the chair for 3 hours last night, for the first time in a long time.

Nice to have Class A again, and a great introduction to tubes.

Thanks for the hand holding guys! :thmbsp:

If I were you I'd take a look at the impedance of the output transformers and maybe try to replace them. I figure they're a large contributor to the high and low end clarity, and Hammond's 125 series should already be an improvement, if you don't want to go with the enclosed models. AFAIK you can't go wrong with using derated OPT's.

I have a similar Magnavox amp using 2 EL84's 1 12AX7 and a 5Y3. Using the origional speakers and cabinets the amp sounds great. What you need to do is in the feedback circuiut there should be 1 resistor 100 ohms I think going to a .1 UF cap with the caps negative end connected to ground. Replace that resistor with one at least 220 ohms to tone down the treble a bit (they had to compensate for the high resistance volume control origionally used with the amp). Also for improved bass replace the coupling caps between the preamp tube and output tubes with at least .1 UF. Also if your amp is similar to mine there should be a 47K resistor connected between the input jack and preamp tube. I would recommend you remove that resistor, connect a 1meg resistor between the preamp tube's grid to ground and connect at least a .1 uf cap between input jack and grid of preamp tube. this protects the preamp tube when nothing is connected to the input jacks and also protects the device connected to the amp should there ever be a shore between the plate and grid on the preamp tube. Same applies for the other channel. The output transformers should be fine. I've tested my amp and with these mods and the origional 12 inch speakers I get down to around 30 Hz and in a 12 ft by 12 ft room it gets pretty loud. Puts out best I can tell around 5.5 watts. What I did for my amp was to install a 100 K dual ganged volume control.

Several years ago my brother won an eBay auction for the same type '60s Magnavox console amp, modified by the seller for plug-and-play use; a class-A SEP with an added power switch, 3-prong AC cord, and fuse protected. It put out about 2-3 WPC driving a pair of 98.5dB efficient Klipsch Cornwalls...with its Ei Elite gold-pin 6BQ5s, a single Electro Harmonix 12AX7, and a NOS '51 Sylvania 5U4G blackplate rectifier, this li'l amp was a fantastic sounding performer mated to the Cornwalls and my 6SN7 SRPP linestage pre. Had I not ordered a 300B SET amp at the time, I would've bought the Magnavox from my bro and had it completely gone over with high quality caps and any other electrical upgrades/mods, new gold plated RCA jacks, 3-way binding posts, then stripped and finished off aesthetically...chrome chassis, wood cabinet all around, et al! It would've been nice...when I received my 300B SET amp, my bro later sold the Maggie after buying himself a Dared 6V6-based integrated amp (that flea-powered Magnavox still sounded sweeter than the new Dared...oh well, you live and learn)! :yes:

If you ever need to replace the power transformer a Hammond 270FX works great. Also do not use a Sovtek 5Y3 they tend to short and ruin power transformers. Construction looks like a 6X5 with a 5V filament instead of 6V. There's nothing quite like the smell of a burnt transformer :)

I was going to offer the schematic, but I see it comes with one... this was built around 1960 (that's the date on my schematic).

7 watts is VERY optomistic - 2-3 watts per channel is more like it. Should be fine with open baffle speakers, depending on the listening level you want. I use similar amps with my computers at work and home.


hi tom,


im a tube newbie and a friend gave me an amp 197 a week ago! and i would like to modify it a little!! will it be possible if i can have a copy of thr schematic...i've read some mods on this thread and i would like to do it with mine!thanks btw it sounds amazing a lot better than my pushpull amp!!!sounds so sweet it makes me weak!!!!!:banana: :banana: :banana: thanks

It depends whether the amp was used with a tuner or just a record changer as to whether they used a 5Y3 or 5U4.

to the thread starter-- how did you determine the size and shape of your open baffles?

blabla check this out if your amp uses 12AX7 driver, 6BQ5 output tubes and 5Y3 or 5U4 rectifier http://audiokarma.org/forums/showthread.php?t=103661 In it I have described some mods and have provided a schematic and parts list with those mods listed. The only thing your amp needs is three nine pin tube sockets and 1 octal socket.

hi tube radio,


thanks!!! il order the parts that i need and ill keep you fellas updated on the improvements...:banana: :banana: :banana:

Ok. And yes there will be a major improvement in the sound of the amp when you are done. :music:

blabla check this out if your amp uses 12AX7 driver, 6BQ5 output tubes and 5Y3 or 5U4 rectifier http://audiokarma.org/forums/showthread.php?t=103661 In it I have described some mods and have provided a schematic and parts list with those mods listed. The only thing your amp needs is three nine pin tube sockets and 1 octal socket.

I got my ol' tube Lambda DC bench supply ready to boogie, and a half-assed breadboard setup on a junk endtable.

I've got the typical magnavox SE 6BQ5 circuit pretty much lashed up with a 12AX7 driver. (So I can roll a few....I have about six 6EU7, and a ton of 12AX7.)

Ala mono, so crosstalk won't be a problem. :)

I'm going to try some of your mods you list in that thread.
It will be nice to quickly change out things with the breadboard setup, noodle around, optimize I suppose...

In terms of how to size the baffles, I experimented with some free s/w, and then asked some questions of folks on DIYAUDIO etc.

I became so enamoured with the resulting sound, that I now use biamped OB subs, and co-moderate this - http://www.audiocircle.com/circles/index.php?board=90.0

And the big monster of all OB threads, this on on AC too - http://www.audiocircle.com/circles/index.php?topic=19253.0