6X4 12AX7 6V6 amp looking for info

[bastardbus]

I picked up this killer looking external amp and speaker set up for a `50s hi-fi for $35 yesterday. I will try and snap some pics later.

The tube set up is 6X4 12AX7 and 6V6. It is a Bell Sound Systems model 305-D. I could not find a schematic or info on this model ANYWHERE on the net but a quick visual of it she looks similar to a 5F2a Princeton with obviously different component values for a hi-fi amp. It has a single volume and basic tone control. It has a nice Power Transformer but obviously there is no 5V tap only 6V thus the 6X4 rectifier.

I had planned on doing a champ-princeton type of thing with it but the 6X4 is something new to me. Is this going to put out the voltage and current needed for something tweed or do you guys have some other suggestions. I want tube rectification so diodes are out and obviously I have to stick with the 6X4.

I heard there is some Silvertone amps that used the 6X4...?

T

[Blackburn]

Silvertone models 1481 and 1482 both use that rect and are great amps, which I have both of. I personally think the 6X4 is a great rect. That amp has the exact compliment as the 1481 and here's a thread on mine...

https://tubeamparchive.com/viewtopic.ph ... silvertone

[xtian]

Looks like it's rated 70mA, so that should be fine for a small tweed.

[Phil_S]

Nothing wrong with a 6X4 and you can probably buy them cheap if you need one. If you don't want to use it, change the socket for a 6CA4 (noval), 6X5 (octal), or just use 1N4007's and skip the tube.

Cheap example here: http://www.ebay.com/itm/NOS-DuMont-6X4W ... 5afe35362a

Even the Chinese are making something compatible: http://www.ebay.com/itm/2pcs-NEW-Shugua ... 4d04efa5c8

Sounds like you have a great platform there. Enjoy it!

[bastardbus]

do you have a schematic for the 1481?

I found some on line but they were pretty sloppy...

Thanks

[Satchmoeddie-II]

You have a keeper. That tube compliment is one I use daily while playing in front of the TV. It sounds great, keeps the noise down, which keep other people in the house sane & happy. I got this GA 79 RTV in, and the front logo said Bell, with Bell on the schematic too, but the control panel says Gibson. I only took pics of the back, I guess. I don't remember if it said Gibson by Bell or Bell by Gibson. I know it said "Gibson", "Bell" & "by" on it, or I'd have never grabbed a camera. Stupid me I never turned the amp around. Which side do I need access to to work on it? Oh well. My best guess is Bell made them for Gibson. It is the Stereo verb & trem amp with El84s in it. I fixed it & sent it on it's way. Could have sworn I took pics of the front, but maybe not. I use a little SE amp with a 6X4 one 12AX7 a 6V6GTA and a 6" The Fisher alnico in it. For a pressed paper silvertone student amp it sounds great, but most of that model had a 5" Quam or a 5" Oaktron speaker, not the 6" "The Fisher." The difference is amazing! I had fixed several of those little Silvertones. This one sounds so much better than the usual 5". Found one! See, a Gibby amp with Bell 30 on the front.

[Blackburn]

Here's the schem that looks right.

http://www.prowessamplifiers.com/schema ... _1481.html

I can't believe they put the volume control where they did and was expecting the worst with it anywhere but dimed, but the amp really does have some mojo, especially the old AlNiCo that comes in Silvertone combos. If you're wanting a simple SE amp, just build it up and put the volume control after the first stage, like the Champ. I'd just ditch the tone control. These amps are so raw and open sounding with just a volume knob. I adore these little things.

[bastardbus]

Thanks for the schematic, not much different then a Champ really just a couple component values.

This Bell sure is a crazy looking thing. Here is some pictures of it with the removable speaker and notice the retro spindle legs. This amp was designed for a turntable, tape or tuner.

I was kinda curious how she would sound as-is so I stuck some new electros and coupling caps in her and she sounds pretty good with a 45 playing through it. Not "Hi-Fi" but gets good and loud with great bass. Plugged my strat into it and obviously she had zero gain. It did have a nice clean sound though.

I was concerned with voltages because of the 6X4 but they were PLENTY high enough for a little tweed or any other SE 6V6 amp. They were almost too high actually! I had 371 on the plate of the 6V6 and 326 on grid. The 12AX7 had 169 and 160 on plates.

[boots]

I've modded a couple old reel-to-reel tape decks into great guitar amps, both had 6X4 rectifiers. One was a Silvertone - don't remember the model number. The 6X4 works great in a single-ended 6V6 or 6BQ5. It's kind of saggy, but I like that.

6X4 are getting hard to find, but they are out there.

[Blackburn]

https://tubedepot.com/products/6x4wa-jan

Cheaper than most new Chinese/Russian tubes...

[Structo]

bastardbus

Now that is friggin cool!

I hate to see this vintage stuff get thrown away.

[bastardbus]

bastardbus

Now that is friggin cool!

I hate to see this vintage stuff get thrown away.

YEAH! I thought it was pretty friggin' crazy when I saw it. I have heard a lot of Bell Sound Systems but have never seen anything similar to this thing! Usually you can do a Google search and come up with some info on any old thing you find but I could not find one single iota of info on a Bell model 305-D ...strange.

The thing that is somewhat tempting is the chassis is pretty big and spacious and the speaker enclosure has room enough for a 12" speaker (though it currently houses an alnico 6x9. I really am tempted to bump it to something a tad more but I dunno...kinda cool to keep the original iron and tube set up and just tweak the circuit to something else.

I rebuild all kinds of `50s hi-fi record players and amps and have been kinda busy so have not got to fool with this much more yet. I have just been playing a little `50s 45 player attachment though it while I am working.

[bastardbus]

bastardbus

Now that is friggin cool!

I hate to see this vintage stuff get thrown away.

YEAH! I thought it was pretty friggin' crazy when I saw it. I have heard a lot of Bell Sound Systems but have never seen anything similar to this thing! Usually you can do a Google search and come up with some info on any old thing you find but I could not find one single iota of info on a Bell model 305-D ...strange.

The thing that is somewhat tempting is the chassis is pretty big and spacious and the speaker enclosure has room enough for a 12" speaker (though it currently houses an alnico 6x9. I really am tempted to bump it to something a tad more but I dunno...kinda cool to keep the original iron and tube set up and just tweak the circuit to something else.

I rebuild all kinds of `50s hi-fi record players and amps and have been kinda busy so have not got to fool with this much more yet. I have just been playing a little `50s 45 player attachment though it while I am working.

[bastardbus]

bastardbus

Now that is friggin cool!

I hate to see this vintage stuff get thrown away.

YEAH! I thought it was pretty friggin' crazy when I saw it. I have heard a lot of Bell Sound Systems but have never seen anything similar to this thing! Usually you can do a Google search and come up with some info on any old thing you find but I could not find one single iota of info on a Bell model 305-D ...strange.

The thing that is somewhat tempting is the chassis is pretty big and spacious and the speaker enclosure has room enough for a 12" speaker (though it currently houses an alnico 6x9. I really am tempted to bump it to something a tad more but I dunno...kinda cool to keep the original iron and tube set up and just tweak the circuit to something else.

I rebuild all kinds of `50s hi-fi record players and amps and have been kinda busy so have not got to fool with this much more yet. I have just been playing a little `50s 45 player attachment though it while I am working.