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Post by Deleted on Apr 7, 2008 3:24:30 GMT
Hi- first post here! I have an old Dobro amp from the 30's in pretty much near mint condition, and working. Original James B Lansing field coil speaker too. I was curious as to the value of it as I've only seen one other and it's in the Experience Music Project museum in Seattle (and not in as nice a condition- also zero info in the exhibit!)    It's pretty cool, doesn't sound like much though. I'm more of an Orange amps guy (also moderate the Orange amps forum) and Marshall, etc. I had gone with my brother, who is really into old radios, to an antique radio swapmeet and found the amp. It was dirty but totally complete! Thought forum viewers might like the pictures! No, not for sale... Billy |
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Post by steverino on Apr 7, 2008 5:55:15 GMT
Bclaire, one interesting historical tidbit is that Jim Lansing's company, Lansing Manufacturing Company, was located at 6900 McKinley Avenue in south central Los Angeles from 1934 until after he sold the company in 1941. In the mid 1930s the Dobro factory was located at 6920 McKinley... right next door. Jim Lansing began spinning aluminum foil dome shaped diaphragms for compression driver theatre loudspeakers in 1935. I wonder from whom he might have learned the spinning technique?
I have an amplifier that was built by the Schireson Brothers in Los Angeles in the mid 1930s. It has a Lansing speaker that looks very much like the one in your amplifier. I can't comment on the value of your amp except to say that as a longtime collector lof Lansing's early work I think it's priceless! Thanks for posting the nice pictures.
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Post by Michael Messer on Apr 7, 2008 9:50:58 GMT
Hi Billy, Welcome along to our forum and thank you for posting photos of your beautiful amplifier. I love the look of these amps - here is the front cover of my 2002 album, Second Mind.  Notecannon Colin and Mark Makin know more about those amps than me, so hopefully they will be able to tell you more about it. As for its value, I don't think any of us can do that as they so rarely turn up in beautiful working order. And without actually seeing it, valuation is not really possible. A couple of things that concern me about it (again Colin is the person to verify this), are that I don't see a 'National' 'Dobro' or 'National-Dobro Corporation' badge anywhere. Usually it would be on the back of the actual amp chassis. Another concern I have regarding its originality, are the two jack plug sockets on the back. Other than those points, I think it looks beautiful and I bet it sounds amazing. Amps from this period are usually quite dangerous as they were not earthed properly. Maybe this one has been earthed and is now safe. What are the tubes (we call them valves in the UK), are they National Union 18s, or later replacements? I hope Mark & Colin can comment about this amp. Shine On Michael |
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Post by Deleted on Apr 7, 2008 10:21:18 GMT
Thanks for the info!
I had it retubed actually, and gone through by an antique radio repairman. I realised that in its electronics it was closer to an antique radio than a guitar amp so it didn't go to my amp tech (who actually didn't want to have anything to do with it). It appears to be totally original, with the two inputs- someone wrote with pencil and drew an arrow for the guitar input. I'll have to go pull it out to see what tubes/ valves it has though later today. I did have the radio guy add a fuse for it for safety, which is hidden within the chassis.
As for missing badges, there are no missing bits that could be determined on it- like holes where a badge might have gone, etc.
Billy
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Post by pete1951 on Apr 13, 2008 15:18:23 GMT
To fellow vinage amp fans
Get your old amp out now and then and give them a gentle play
The power caps. need charging to stop them degrading. The caps. do degrade with use,
but no use at all is a slow and lonley end for something that could be making beautiful music,
Pete
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Post by billyclaire on Jun 22, 2014 23:34:46 GMT
Sorry for resurrecting an old thread, but I was doing some online searching for info and discovered that I joined the forum back in 2008! I had no recollection of that (must be getting old!)
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Post by Stevie on Jul 11, 2014 22:29:29 GMT
To add to Pete's assertion regarding caps, electrolytic caps do not appreciate not being used regularly either. The dielectric degrades without regular use. Obviously this varies from cap to cap, but I have a very old National (no relation I believe) HRO receiver and a similar but even heavier RCA AR88d receiver and I try to run them up once a year for this reason. Electrolytics can be reformed by running the equipment up to full working voltage slowly through a variac autotransformer. Regular usage obviates this need. I had an 8 amp example once, but I sold it long before I realised how useful it would become. For a vintage amp afficionado, a variac is a very sound investment. For us Limeys, a 110 volt transformer would be a halfway house approach if the vintage equipment has not seen.active service in a few years. I run an extension lead down to the shed and switch on at the house just in case a smoothing cap goes. The mess and the smell is indescribable when they do blow.
e&oe
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Post by mitchfit on Jul 11, 2014 23:32:16 GMT
bclaire, would ~guess~ the below amp jpg's and yours to be very close to the same D.O.B. also guessing yours is the earlier version due to it not having an included fuse. seems these were mfgd before national/dobro created the valco amp enterprise as the mfgr plate states it is "Webster Electric Company" built in Racine, WI. best bet for schematic search would be "National-Dobro Amp 6107" as per jpg listings. the relocation of amp controls/inputs/fuse LIKELY non-issue with component values, tubes/valves and circuit layout unchanged. purely speculation, but the below list from: home.provide.net/~cfh/dobro.htmlhas a very good chance of applying to amp serial #'s also. you'll need to verify same... Dobro Serial Numbers 1929 to 1937 Dobro Serial numbers by M.Cass. Note the 1929 to 1937 serial number info is not very accurate. For example I own a Dobro metal body M-62 with the serial number 1832. According to the list below it should be 1930. But no metal body Dobro existed before 1935. So you can see the serial number info below is not 100% reliable and the information below applies mostly to wooden body resonator Dobro guitars. Pleaes keep this in mind. Also I don't have any 1937 to 1942 Dobro serial number info. Serial numbers for metal body Dobros very scarce. Serial numbers are stamped into the top of the peghead. No factory serial number records are available. The numbers below are a general guide, and are not reliable for dating the instrument solely on the serial number. Number range Year 800 - 1400 1929 1400 - 2000 1930 2000 - 2600 1931 2600 - 3200 1932 3200 - 3900 1933 4000s 1933 (mostly Regal made) 5000 - 5600 1933 (California made) 5700 - 7600 1934-1936 (California made) 8000 - 9900 1936 & 1937 L9000s 1937 (Regal made) A prefix 1936 B prefix or suffix 1931-1932 (most Cyclops wood models) M prefix 1935-1937 No serial number: on 1930s Dobros, this happens a lot, and for no explainable reason. below brought to you courtesy of Terry Dobbs AKA Mr. Valco. [valcoamp.com] one of THE sources for jurrasic period national/dobro/valco electronics. www.valcoamp.com/photo/nationaldobro-amp-6107-1?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-2?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-3?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-4?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-5?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-6?context=latestwww.valcoamp.com/photo/nationaldobro-amp-6107-7?context=latestthese and differing [same period] reso-cover plate design speaker grill amps turn up on the 'bay from time to time. just keep searching for similar amps that ~do~ sell, and keep records of relative condition compared to your amp, and price. the end results will need to be averaged over the period it takes to collect a meaningful amount of data base. hope this helps, mitchfit PS...overall--current {US of A} pricing is down from, say 3-4 yrs back. but starting to pick back up again. |
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Post by mitchfit on Jul 11, 2014 23:42:32 GMT
^^^
also, if you live in 50 cycle country, avoid diming the amp volume too much as a marginal output tranny will suffer from extensive use being a 60 cycle design.
mitchfit
EDIT
RETRACTION. JUST READ THE AMP SPEC PLATE AND 50 CYCLE POWER IS WITHIN DESIGN SPECS.
OR--large variations in armature RPM's from rural power sources back then?
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Post by billyclaire on Jul 13, 2014 1:46:43 GMT
It definitely isn't a 6107A. It is exactly (electronically) like this amp: prewaramps.org/natdob2a3.htmThe 6107A is a shorter box with rounded corners - mine has a pointed design and a taller cabinet - plus a totally different electronic schematic. Don't know if LA278 is a serial number or model number. Mine doesn't have any kind of ID plate nor does it have any place where it could have attached (no screw holes, etc.) Don't think they ever glued them. Tubes are: 56, 57, 5Z3, and two 2A3's. Simpler electronic layout than the 6107A's. 6107A has a 79 preamp tube which was introduced a year after the 57. |
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Post by billyclaire on Jul 13, 2014 1:57:46 GMT
Look at the corners of the amp in this old ad: www.notecannons.com/catalogues/tonk_bros_14.jpgIt has the pointed corners and tall box that mine has although a totally different coverplate. No idea what year this ad is from (from notecannons website) |
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Post by skydog on Oct 18, 2014 17:01:51 GMT
Hi ho il privilegio di aver trovato funzionanti un MOODY Made in Sydney 1950 and a VEGA commander for laap steel all tube -sounds great whith guitar and Harmonica !
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Post by skydog on Oct 18, 2014 17:06:55 GMT
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Post by skydog on Oct 18, 2014 17:10:09 GMT
Questi invece sono Italian Vintage Eccezzionali ELKA TX6 suona come un Champ e il TX20 ha un vibrato eccezzionale ricorda Ry Cooder -un Ariston 5 watt e un SOUND STUDIO tutti a valvole anni 60 -
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Post by skydog on Oct 18, 2014 17:15:30 GMT
Questi, invece Sono italiano Vintage eccezzionali ELKA TX6 suona venire ONU Champ e il TX20 ha ONU vibrato eccezzionale Ricorda Ry Cooder -UN Ariston 5 watt e SOUND STUDIO ONU Tutti a Valvole Anni 60 - |
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