Hello!
I recently acquired a 1938 EH 150 and am currently restoring it. I was wondering if anyone happens to know of a schematic for this model, since the schematics that are easily available are either the early or the late versions of the amp (not this version with 3 6C5s).
There was another thread from several years ago that looked very promising, but the links are dead.
Thanks for any help!
-Matt
I recently acquired a 1938 EH 150 and am currently restoring it. I was wondering if anyone happens to know of a schematic for this model, since the schematics that are easily available are either the early or the late versions of the amp (not this version with 3 6C5s).
There was another thread from several years ago that looked very promising, but the links are dead.
Thanks for any help!
-Matt
mattnorthrop said:
One thing about those old Gibsons, they varied as much as Chicago's weather amp to amp.
Are you certain it is not actually a EH100? They used 6C5's in those.
The 50's version
EH100 Schematic W/6C5's
The 60's Version
The 60's version
OR,
Could it be the EH160 in a EH150 cab like a transition year?
EH160 w/6C5's
I'll dig in my archives to see if I have others.
Many thanks for your reply.
The chassis is marked EH-150. The guy I bought it from said it was a 1938 model, which seems to fit with the Gibson Amp Project website's (hem.passagen.se/ekabjan/GibsonAmps.htm) listing of a EH-150 model with a three 6C5s and one 6F5 preamp section. Also, it does have the 5U4/6l6 power section that fits with the EH 150/185 circuit.
I think you are right, though, that its some sort of a transition circuit.
Again, thanks for your time!
-Matt
The chassis is marked EH-150. The guy I bought it from said it was a 1938 model, which seems to fit with the Gibson Amp Project website's (hem.passagen.se/ekabjan/GibsonAmps.htm) listing of a EH-150 model with a three 6C5s and one 6F5 preamp section. Also, it does have the 5U4/6l6 power section that fits with the EH 150/185 circuit.
I think you are right, though, that its some sort of a transition circuit.
Again, thanks for your time!
-Matt
So, I think I just luckily stumbled upon it at this website:
http://prewaramps.com/gibsoneh-15.htm
Pretty fascinating pictures of one of these.
http://prewaramps.com/gibsoneh-15.htm
Pretty fascinating pictures of one of these.
mattnorthrop said:
That baby looks sweet, Nice Find.
I just added that schematic to my collection,
Good luck getting it restored, I bet it will be a great amp when its done.
Thanks for your help with tracking down the schematics. I Got around to going over the amp, and it sounds great.
However, I have a question for those of you familiar with these:
How loud are these amps, typically? This one does not seem to be as loud (or maybe breaks up earlier?) than something of comparable output, like a fender tweed deluxe (or is this comparable?). The instrument channel proper is not loud at all (not much louder than just strumming a solid body). I replaced all the filter caps, coupling caps and any drifting resistors, and the B+ lines, as far as I know, seems ok (400v+). The amp sounds good (distortion on the mic channel turned up is pretty amazing), but is just not very loud.
Could any of you all with more experience enlighten me? Is this amp functioning as it should, or is there a potential volume problem?
Thanks again for all your help!
However, I have a question for those of you familiar with these:
How loud are these amps, typically? This one does not seem to be as loud (or maybe breaks up earlier?) than something of comparable output, like a fender tweed deluxe (or is this comparable?). The instrument channel proper is not loud at all (not much louder than just strumming a solid body). I replaced all the filter caps, coupling caps and any drifting resistors, and the B+ lines, as far as I know, seems ok (400v+). The amp sounds good (distortion on the mic channel turned up is pretty amazing), but is just not very loud.
Could any of you all with more experience enlighten me? Is this amp functioning as it should, or is there a potential volume problem?
Thanks again for all your help!
It might be a symptom of the low efficiency field coil speaker?
I would think you should be nearly as loud if not close to bettering a Tweed Deluxe.
Part of the charm of those oldies is in studio use. Not overly loud, but outstanding distortion and fairly fat cleans.
I would think you should be nearly as loud if not close to bettering a Tweed Deluxe.
Part of the charm of those oldies is in studio use. Not overly loud, but outstanding distortion and fairly fat cleans.
I can't help but wonder what it would sound like connected to an magnetized speaker (I'm not going to do that, though!).
Thanks for your help!
Thanks for your help!
Have always wondered how transformer-coupling would sound in a guitaramp but never tried.
My planned next project is a PP B4G with Lundahl IT/PI in a Princeton chassi with the same cabinet and Weber 15" as in our Pro amp.
About old Gibsons I have rebuilt both a brown GA-20 and GA-35. Like old Gibsons better than Fenders.
Never had a chance to lay my hands on an old EH-150 though. Do you have the ES-100 with Charlie Christian pickup to top it up with standing i the closet😎?
About low output level have you changed the 6L6s or measured cathode voltages?
Hi. I came across your thread by accident while searching for something else. Prewaramps.com is my website. The Gibson EH-150 shown in the pictures is also fairly clean and quiet on the normal channel. The microphone channel picks up where the normal channel leaves off, and gives a fabulously thick overdriven tone. There are clips recorded from each channel in the "Clips" section of the website. This is a terrific amp. Hope this helps.
Thanks for your reply!
Out of curiosity, how does the volume/breakup level compare to something like a tweed deluxe or princeton?
Also, thanks for the schematic you posted on your website. It was very helpful in fixing the amp up.
Out of curiosity, how does the volume/breakup level compare to something like a tweed deluxe or princeton?
Also, thanks for the schematic you posted on your website. It was very helpful in fixing the amp up.
tubefever said:
Lots of great information. I think this is my favorite: http://www.prewaramps.com/natdob2a3.htm
Hi--the Normal channel is loud enough for polite soloing--loud enough to compete with a piano, or a snare with brushes. It doesn't approach even a Princeton in volume, and it is pretty clean all the way to the top. The microphone channel is another story, though it is more impressive for its distortion than its volume. You know Charlie Christian must have plugged in here a few times. I can't remember the voltages and currents off-hand, but I assume they are low by modern standards. I'll measure them again next time I have it open.
The field coil speakers have a big effect on the sound of all of these amps. There is a "dryness" to the mid-range that is instantly recognizable from old recordings.
Good luck with your restoration. The yellow box capacitors are beautiful, but unfortunately not well sealed. They leaked dielectric all over the inside of the cabinet!
The field coil speakers have a big effect on the sound of all of these amps. There is a "dryness" to the mid-range that is instantly recognizable from old recordings.
Good luck with your restoration. The yellow box capacitors are beautiful, but unfortunately not well sealed. They leaked dielectric all over the inside of the cabinet!
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