New Baldwin Organ Amp Project

[Platefire]

Here is some pixs of the Baldwin Organ amp. I've been thinking I could probably use existing chassis, gut it and rebuild it but it would be quiet a job and it wouldn't be too pretty when I got through. I've been looking at the Marshall 18 and the 2022 except I don't need but 1 input/1 channel and could use the other 12AX7 stage for some other activity! Platefire

[jojokeo]

I don't see where the extra ax7 socket is that you're referring to? 18watt lite = 2 ax7s & 2 el84s.

There's not a lot of room for many controls. The input where the wires come out, a vol, tone or treb & bass, and a master leaving enough room for a light or light & switch or a switch w/ a light built in. Remove the two can caps and your board will fit nicely there.
You could drill and add a socket for say a low heater drawing pentode safely enough and maybe hit it after one or two ax7 stages?

[RicharD]

The chassis is rough but with a little steel wool and a shot of clear coat, it'll be fine.  On the back I'd force a square peg into a round hole and put an IEC where the remote speaker is.  Leave the fuse and put the power switch where the power cord is.  Yank that pot and put the speaker jack there.  Looking at the gut shot, you can pull everything in the top left corner.  This makes room for a cap farm or maybe a choke.  I'd make the face the side that is at the bottom of the gut shot.

That thang scream Stout although there are many possibilities.  IIRC, the blue secondaries are 15 or 30V.  You could do a fixed bias circuit pretty easily.  Personally I think 6BQ5's are better run cathode bias.  I would do a EF86 V1 and copy the Stout from the PI back with the addition of a tilt switch at the PI tail.  Them old Baldwin output transformers sound fabulous.  They're worth pulling and using in a ground up build if you're up to punching a chassis, otherwise it can be done on the cheap for the cost of resistors, capacitors, and the whatnots.
 

[Platefire]

Thanks for your suggestions! I took a look at the Stout and I like that a lot. About what I had in mind. Pretty sure it will be a Stout. I'm strongly considering putting it in another chassis though. I been thinking about an 18 watter for a while and thinking I may as well do it right. I took a look at the Stout pictures in Dougs library and think I've got another old 100 watt chassis I could cut down and plate up the holes like those pixs and have a lot more room. So I'll go dig that old chassis out and have a look and see what the possibilites are. Platefire

[sluckey]

I just recently converted an old Hammond AO-39 to an 18W Lite. I was back and forth between Doug's Stout and the 18W Lite for several days. Tossed a coin and the Lite won. Here's my project. It may give you some ideas. You have enough real estate on that old chassis to build either.

http://home.comcast.net/~seluckey/amps/hammond/hammond.htm

[RicharD]

The Stout is a cool circuit.  I add a switch at the PI tail to switch the wiring between typical and Doug's tilted mod.  I usually don't mess with the clean/OD switch and wire it straight over drive.  The next one is gonna have a EF86 front end.

[jojokeo]

I like Doug's tone control, is that a "low loss" type that's w/ a twist from the standard Tweed type tone control? It's one of those "why didn't I just do that" things that's right there infront of your face but failed to see.

The Stout is a cool circuit.  I add a switch at the PI tail to switch the wiring between typical and Doug's tilted mod.  I usually don't mess with the clean/OD switch and wire it straight over drive.  The next one is gonna have a EF86 front end.

Could you expalin the "tilt" control please? I'm not familiar w/ that. In fact today's the first time I've seen the Stout in maybe a year or more.

On the EF86 I just designed an amp w/ both the EF86 and a stage of an ax7 both hit from the input jack similar to a paralelled ax7, each w/ thier own vol & gain controls. That sounds fun to put w/ this? I don't see much diff btwn the 18watt & Stout PA sections?

[RicharD]

see attached.

[jojokeo]

Thank you, now what does it sound like when the switch is flipped?

[sluckey]

Doug's tone control is straight up 18W Normal channel.

[RicharD]

With Doug's PI mod, the output of the PI becomes unbalanced.  This makes 1 output tube amplify more than the other.  It doesn't really seem any quieter but there are a lot more over-tones when heavily over-driven.  Someone equated it to being similar to running a output tube amp with only 3 output tubes.

[Platefire]

Sluckey

Took a look at your Hammond project and that turned out real clean. You didn't comment on how it sounded, so I was wondering? I think your chassis is a little longer than mine and your transformers are layed out in better locations than mine. If I was to use the existing chassis I would be inclined to put the controls oppisite end of the transformers even though it does have a mounting flange sticking out on that side. Also I would be inclined to just go with p to p like you did instead of trying to fit a board in there. I actually have a metal bottom plate that I didn't show that covers the bottom and bolt holes match those on the flanges. I'm thinking I could bolt some small rubber feet through those holes to make it stand up a bit. So if I do use my existing chassis this is what I think:

1-Gut all the existing circuit, remove can caps and possibly remove those old plugs and put a cover plate over them or either leave them in place and remove the existing components from them and use their connectors like terminal strips for my own circuit. So at that point it would be just transformers, tube sockets and existing terminal strips left.

2-On the rebuild install filter caps on two new terminal strips parallel to each other approximatly in the space between rectifier and preamp/PI tubes. On the side of the "new front" where the Accessory & to Console plugs are, I think I could fit a pilot light, power switch and standby in that area. On the other end of "new front" with the filter cap cans removed install the input jack, volume, tone and any switches.

3-On the rear as Butterlicious suggested leave fuse as is, pull pot behind OT and install speaker jack there but I believe on the IEC cut it in centered where existing power cord hole goes in. The two plug sockets on that end could either be left in place or removed and covered with a plate. I would be inclined to just leave them in place.

I think that just might work. I will have to layout the "new front" to see if everything will fit. I could also see me installing some handles in the side to make it easy to pick up. Does that sound like a workable plan for existing chassis? Thanks, Platefire

  

[sluckey]

The sound is typical of the Marshall 1974 amp. Plenty of youtube demos for 18 watt Lite. Here's one...

My amp is the Brown Note Lite IIB but with only one input. My preamp is hardwired parallel triodes.

I think your plan is a good one. The only change I would make would be the filter caps. I'd remove the 'Accessories Plug" and "To Console" plug and mount two cans in the empty holes. Using cans in that chassis will give a lot more room under the hood.

I'd hold off on any permanent decisions about layout until the chassis is stripped down to just trannies, tube sockets, and terminal strips. Once you see the empty chassis you may have some other ideas about layout.

[Platefire]

sluckey

I'm one of those caught up in the Twilight Zone of "Dial up" internet so all those vidios that everybody else downloads in nothing flat, it would take me all night long to download one of those youtube files----someones always linking one to give an example but I'm just not equiped right now. I live out in the country so there is no TV cable/internet here.

Guess I'll just have to find out for myself.

On the filter caps, if I put those cans in those old plug locations that will be right where I would be putting my input jack, volume/tone pots and I don't think that would be good---but as you say I will clean house and then take another look at it then. I was just thinking also, if I follow Dougs Stout plans I will also have to make room for a choke too. I've got a used one that came off a PP 6V6 Dean Markey amp that should work. Thanks, Platefire

[sluckey]

This is what I was talking about... Move the caps over, freeing up plenty of space for the input, vol., and tone, plus they will all be near the preamp tube. Put power, indicator, and STBY (not needed IMO) near the moved caps, keeping high power AC away from the sensitive preamp tubes and circuit. Makes sense to me but there are many ways to skin a cat.

EDIT... Modified pic to show location of choke if used.

[Platefire]

Yeah I see what you mean! I guess the reason I was pulling for my plan is I have some existing caps I wanted to use but can see the wisdom of keeping them far away as possible from preamp tubes. Once a skin flint always a skin flint I'll take a look at Doug's cans. Looks like I'll need a 40 and three 20's. It appears to me the only logical place for the choke is between the rectifier and preamp tubes?! Platefire

[sluckey]

I wouldn't bother with a choke on a Marshall 18W.

[Platefire]

So I guess about 2K/5W in that slot.

[RicharD]

2k sounds right.  I did a dual output variant of the Stout and used a 1k, but that pulls roughly double the current, so 2k should work.  It also uses a Concertina PI.  Here's the schematic. 

[Platefire]

Man! There is a lot of variations of this type amp(Stout/Marshall 18/2022). Your schematic has 4-EL84's---how did it sound?
I use my guitar volume like the old blues players on a tweed amp. The more variation I can get from total clean to full blown natural tube distortion---and everything in between is desirable--but a must is I've got to have some decent clean when I turn down the guitar volume. On cleaner sounding amps, I just use my Route 66 OD. It would be nice to get it all with just my delay pedal being the only effect. Thanks, Platefire 

[Platefire]

I was looking at Dougs 40/20/20/20 Can for this project. Man! That takes a 1 1/2" hole---To do that I would have to go buy an new hole saw or is there another el-cheapo way?

I've never installed a new can before, so I guess I would need to buy that mounting ring to go with it, huh? Thanks, Platefire

[RicharD]

>Man! There is a lot of variations of this type amp

There's a whole forum dedicated to variants of this topology.

That particular amp was super sweet.  I was able to reuse a bunch of existing components including "dog bone" wire wound resistors and wax caps.  I'm a total minimalist.  I use no pedals.  The amp I'm using right now is another dual Stout wired hot (no OD switch).  I play a Tele and dialing it's volume back and switching to the middle position gives me good clean twang.  I set the amp itself to eleven.  Here's THAT schematic.
 

[DummyLoad]

I was looking at Dougs 40/20/20/20 Can for this project. Man! That takes a 1 1/2" hole---To do that I would have to go buy an new hole saw or is there another el-cheapo way?

I've never installed a new can before, so I guess I would need to buy that mounting ring to go with it, huh? Thanks, Platefire

use 2 cans. 32/32 or 50/50 and a 16/16 - both are 1 3/8" and will fit the existing openings - only thing you may need to drill mounting holes a but further apart. yes, you'll need mounting clamps.

--DL

[Platefire]

Butterlicious--Glad to meet another Tele fan. I use a few pedals but can get by without them but must have my delay pedal. My amp volume hardly ever gets above 6. On your schematic if I'm reading it right, you plug into J1 you running through both amps and J2 only one side?

DummyLoad---The existing main can has a 1 1/4" hole but the plan was to remove the existing cans because the input jack, tone & volume was going on the left side and the new can was to be set up on the right side where the pilot lite, power switch and standby were to be. So the right side is where the plugs are and the holes are 1". Even the 1 3/8 would be too big for that. I'll come up with something! At the point Sluckey's advice sounds right on "tear out all the un-needed stuff and then take a look at it then" Platefire  

[DummyLoad]

use 2 cans. 32/32 or 50/50 and a 16/16 - both are 1 3/8" and will fit the existing openings -

let me re-phrase - they will fit better in the holes that you plan to use, i did not mean the original cap holes. so sorry for the confusion.

--DL

[RicharD]

The idea behind that amp was for it to be capable of being a true stereo amp so if I ever got a stereo pedal I could use it to it's fullest.  Plugging into J1 does feed both channels.  I mostly use just one side.  The speaker of choice is a pair of 10" Eminence Legends.  Ironically I sold this amp but ended up in a band with the buyer.  He's playing bass.  I've sold all my amps except for the first 2 I built and neither one of them are very good.  I've got most of the goodies to build another one but just haven't gotten around to it.

I love the Telecaster.  Mine is a cheap Mexican Tele with good pickups.  Truth be known I paid twice as much for the pickups as I did for the geetar itself.  I have a phobia about pointy guitars.  I do like Stratocasters and I don't really consider them pointy but I am heavy handed and when you pop a string on a Strat, the whole tuning goes south.  Also being heavy handed with a whammy bar tends to cause tuning problems too.  Les Pauls are great but kinda outta my league.  I've always found the Tele to be the most comfortable for me. 

[sluckey]

So the right side is where the plugs are and the holes are 1". Even the 1 3/8 would be too big for that. I'll come up with something!

The body of the can does not have to fit thru the hole, but the three terminals do. A 1" hole would be too tight for my comfort.

I've been using a 1" CONDUIT knockout punch for those cap cans. This punch actually makes  a 1 11/32" diameter hole. That provides plenty of clearance around the three terminals, yet is small enough to prevent the body of the can from passing thru. It's just about perfect! You can get a cheap 4 piece set for about $15 from ebay or Harbor Freight. I wouldn't want to make a living using cheap punches but they're OK for my occasional use.

I had to enlarge these holes. Take a look... http://home.comcast.net/~seluckey/amps/hammond/closeup.jpg

[Platefire]

Thanks Slucky--I'm totally convinced that I can alter one of those socket/plug holes to enlarge it and install Doug's 40/20/20/20 cans in there--opening one hole up toward the back instead of front. It might take an extra effort but I think with careful use my Dremel cutting wheel I could pull it off. Get Doug's can on hand to reference and take it easy. Also the guy that plays bass with me is the maintenance superviser at our local hospital and I would bet he has a punch on hand he could let me borrow for this. I think I can get r dun without buying any new tools. Next step I think would be to demolish/clean house and make a material list.

Butterlicious-Ok I see how a stereo pedal would work with that. I played in stereo about ten years ago
with the band I was with at the time--was kinda fun and different. On my teles, I got a Hwy 1 that I just put brass conpensating bridge on it--like eveything else. I recenly aquired a Affinity Squire Butterscotch Tele on a trade. The neck pickup was weak and it had a terrible hum. I bought a stu mac sheilding kit, wiring kit, installed a golden age neck pickup, did my own set up and Man! that thing is a player. Hwy 1 has been parked lately!   

[jojokeo]

On my teles, I got a Hwy 1 that I just put brass conpensating bridge on it--like eveything else. 

Did that on my '78, then installed a 4-way switch for the extra series posistion - this is highly suggested if you haven't tried it or done it?