noob questions about EH-150's/185's

[campusfive]

I've got a couple questions that the brain trust here might be able to answer. I've got three Gibson EH amps, a 1936 EH-150 (type II), an EH-160 (the bizzarely low output AC/DC version), and a 1939 EH-150 (type I - transitional model, it's actually stamped EH-150).

The 150 is pretty fragile, so I don't gig with it. And the 160, while in breathtaking shape, barely puts out any volume compared to the AC version. The circuit is totally different, is just oddly under powered. But the 185 is my main gigging amp. I stopped carrying the chasis in the cabinet, and have separate gig bags (from Studio Slips) for each.

My most pressing concern is that the cabinet is getting pretty beat up. I'd like to simply get another 12" field speaker and put it in one of these cool Vintage 47 cabs: http://www.vintage47amps.com/files/index.php?id=72
And then just run a speaker cable from the extension cab back to the chasis.
1) Am I right in assuming that the original speaker in my amp is an F12? The stamp reads "12 F 2" just like the one in this picture: http://reconingspeakers.com/wp-content/ ... 8444-5.jpg

2) When looking for a replacement speaker, do I still need to check the resistance on the speaker to see if a replacement will match?

3) Based on this post (http://bb.steelguitarforum.com/viewtopi ... 0a9663dddd) it seems the "echo speaker" jack doesn't require a field coil speaker, and you could just use any 8 ohm cabinet. So, I'm assuming you'd still need to have the original speaker plugged in so the field could act as a choke?

4) I'm incredibly interested in picking up a clone if anybody's got one or wants to make one.

Any thoughts? There's a bit of info on these amps scattered around, so based on some previous discussions on here, you guys probably know more than anybody else. THANKS!

FYI - this is what I do with them (or least this is what I sound like dicking around at home): http://soundcloud.com/campusfive/moppin ... guitar-jam

[rp]

Welcome. Awesome link to 47amps, especially this:

Watch for the Vintage47 Fieldcoil Speakers, 8", 10" and 12" models coming soon; Direct retrofit replacement for originals with humbucker coil and long lead wires. Fieldcoils made by Heyboer Transformers, Vintage47 Speakers are all made in the USA!

You get my vote for post of the month. I always wanted to do a CC type amp but didn't feel like doing it w/o the FC. Plus those '40s style repo cabs are terrific, too damn bad I'm now in Italy. Anyone flying to Pisa and want to carry one with them, and a field coil spkr?

If he doesn't show up you should PM Colossal, he's the resident Gibson EH man, make him aware of your post, M Fowler too.

I would call 47amp (not email) and sweet talk them into making you a repo cab and offer to pay an upcharge. You can take detailed measurements and pics of yours and email them. Maybe they are interested in offering a true CC amp clone and you can help each other out? You can also try Mather Cabs, Mojotone, Swanson, Memphis Cabs, etc... or TAG's own Taylor 'Amplified Nation'.

I'm pretty sure your FC needs to be attached as it's your choke, but you might be able to add a switched jack or just a switch that switches the OT from the FC to the external speaker (making sure it's already plugged in.) I would do a pine repo cab and carry it as a combo. I hate combos for the weight but old pine 20W amps like this are very light.

Nice playing, cool little riff, reminds me a bit of Misterioso.

BTW we love picts here, how about some clear, detailed, comprehensive, internals of at least the EH-185 and the 150? Might win you poster of the month twice in a row.

[campusfive]

THANKS!

I actually called the guy a year or two ago asking about CC stuff. He wasn't interested in doing anything outside of the Valco-inspired stuff he's doing, but he offered to take a look at the 185 schematic and see what of his amps had the most similar circuit. Also, he indicated the field coil speaker option would be a ways off (although that was many months ago, so who knows?).Super nice, though.

I'll see what I can do about putting up some pics of the various amps. Gotta pay it forward, right?

[Structo]

Couldn't you use a choke or power resistor to simulate the field coil and use a regular permanent magnet speaker?

What do you guys mean by CC?

[Colossal]

What do you guys mean by CC?

Charlie Christian. 30s-40s era swing jazz.

[M Fowler]

What do you guys mean by CC?

Charlie Christian. 30s-40s era swing jazz.

Yeah baby sweet tone!

Mark

[M Fowler]

I'm incredibly interested in picking up a clone if anybody's got one or wants to make one.

I built a chassis no cabinet for it so far but mine is based off the newer EH150 with field coil speaker replaced with a choke.

Mark

[rp]

I actually called the guy a year or two ago asking about CC stuff. He wasn't interested in doing anything outside of the Valco-inspired stuff he's doing..

I'm guessing he bought the rights to the Valco name as a business venture, and that's all he's interested in. I was hoping he was more of amp-obsessed maniac builder always looking for a cool challenge. Shame, he's 70% of the way there on offering a good EH185 CC repo, looks like he has all the necessary crafters on hand. And as long as it doesn't say Gibson EH-185 you could sell all you wanted too, call it the CC-185. Doesn't even have to be flip-top could just go into a stock Tweed type combo with some '30s decorative flourishes. Maybe too expensive, no market, but I bet there's a solid small one. More than a few winders offering CC pickups now, somebody wants this stuff. But I'm the last guy that should offer up business decisions.

Your tone is killer btw, you can hear it even past the MP3 and laptop speakers, if you want that early Jazz tone there's just no way to fake it. Is yours the Vol/Bass/Treb, or Vol/Tone model? Were you using the mic or instrument channel? If you got the skills, better for me than pics would be a voltage chart, even if just 6L6 Plates and the AC across pins 4 & 6 of the rectifier, the latter most of all. But if you don't know how to do this - don't! Maybe got a tech that can blue-print it for TAG?

Waiting on an PT for my 5C8, then must build my Rocket, then I feel something from the Pleistocene, something with grid/anode caps, coming on... like a EH185.

[Masco]

I'm incredibly interested in picking up a clone if anybody's got one or wants to make one.

I built a chassis no cabinet for it so far but mine is based off the newer EH150 with field coil speaker replaced with a choke.

Mark

Hey Mark,

What value choke? Is there anything else you did different from original? Schematic? And, is FC really important to get the tone?

Thx

[Colossal]

Hi Campusfive,

Great tone you are getting! Here is a photo of an amp I built for a local jazz player. The tone of this amp is very, very similar to the clip you posted. It has that woody characteristic tone. This amp was based on a Style IV EH150 with some small changes here and there. Charlie Christian actually had a Style III (different preamp tube compliment). It is not necessary to use a field coil to get the tone, a choke works well as a substitute.

I am working on a paper on the EH150 and have the help of a gentleman who has a very nice collection of originals. I have collaborated with his tech to document the voltages throughout a well preserved Style III. The later EH185 is very similar to the 150.

[M Fowler]

I'm incredibly interested in picking up a clone if anybody's got one or wants to make one.

I built a chassis no cabinet for it so far but mine is based off the newer EH150 with field coil speaker replaced with a choke.

Mark

Hey Mark,

What value choke? Is there anything else you did different from original? Schematic? And, is FC really important to get the tone?

Thx

Colossal I always smile when I see your beautiful amp.

Masco, this amp was built from the schematic of Tino Zottla attached.
The choke is 10h 100mA

Mark

[campusfive]

Wow! That's what I'm talking about!

I'll try to snap some pics tonight anyway, but I'm probably out of my depth trying to use a voltmeter.

The amp in the mp3 is the type II EH-150 with the 10" speaker (original, but reconed by OC speaker), square top cab, a single tone knob and the bass/treble switch). It's worth noting that I'm playing a guitar with a real CC pickup in it. I think the magical tone combo for me is that pickup, octal tubes and field coil speakers. Oh, and I usually use the mic channel for the increased overall volume, I'm not necessarily interested in more breakup, though. I think it's also worth noting that I used to have the pickup a lot further away from the strings, but recently raised them. There's a zingy treble in the mp3 (recorded on my iphone's voice memo function) that I think has something to do with the raised pickup.

On the subject of FC vs. PM, I feel like there's a still response difference, even if there might be less of tone difference, with the FC having a unique response due to the dynamic field.

The 1939 EH-185 that I gig with is the type 1, with both bass AND treble knobs. It's an early one, because it's stamped EH-150. I've read they were planning to change the 150 model to the 185 specs, but then decided to create a new model number for the new design instead.

I've never played through a type IV 150/185 (the same circuit, only difference is the cab/removable chasis), but I know my friend Whit Smith likes those better than the 185 with both tone knobs, but then again he uses a type III 150 normally.

I can't say that I'm that picky as to have strong feelings between the various versions - but all of them are my basic ballpark. I do know that the 10" speaker probably won't cut it live. So, it'd still have to be a 12".

One more wild idea? Is there anyway to double the power stage, kind of like the Victoria Double Deluxe. (or perhaps 1.5x if not double). I'm often in venues where I'm just shy of loud enough sans miking my amp, and turning it up only adds saturation. Could you imagine an EH/CC style pre-amp into a power amp, perhaps with a switchable 2 tube/4 tube option. That would be some serious shit. Stage and studio friendly! Still, I'd be happy just to have a working 150 clone that doesn't involve risking my original amp at every gig.

[Structo]

Yes but it would probably change the whole character of the amp.

The output transformer and the power transformer would likely need to be changed for four power tubes.

[Gibsonman63]

A little out of the box, but maybe a separate OT feeding it's own field coil speaker to run four output tubes?

[Colossal]

Wow! That's what I'm talking about!

One more wild idea? Is there anyway to double the power stage, kind of like the Victoria Double Deluxe. (or perhaps 1.5x if not double). I'm often in venues where I'm just shy of loud enough sans miking my amp, and turning it up only adds saturation. Could you imagine an EH/CC style pre-amp into a power amp, perhaps with a switchable 2 tube/4 tube option. That would be some serious shit. Stage and studio friendly! Still, I'd be happy just to have a working 150 clone that doesn't involve risking my original amp at every gig.

You could do a 2 or 4 switchable tube version but I would to take the entire EH150 design into context and what your goals are. The original is a true class A cathode biased amp and that's an important part of the sound. With a pair of 6L6G (not GC), it puts out about 13-16W. It's a very comfortably loud and full sound, just perfect really for small live performance in an ensemble, solo, and jamming at home. My thinking is if you really are looking for a clone with the tone, I would probably stick to the topography of the original.