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KCA NOS Tubes has always been a good source for NOS stuff.
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09-09-2019 07:34 AM
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TAD makes a nice 6SL7!
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Okay, so I need some help concerning my octal project.
As a student I'm on a tight budget, but still i want to get into octal territory. I have this old Tube overdrive Pedal (Behringer VT-999) which I rarely use. Basicaly It's an external Tube preamp using a 12ax7.
I bought an 9pin to octal Adapter, and wanted to replace the 12ax7 with a 6SL7, what (according to a lot of forums I've been digging through) should work.
Yesterday I got around to testing it and it didn't do anything at all.
With the octal Tube plugged in Not even the Power LED of the Pedal will light up. When i switch back to the 12ax7, everything is fine.
Anybody got an idea what I'm doing wrong?
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Most adapters, I should imagine, are designed with the idea that you will be replacing a 9-pin _power_ tube (e.g., the el84) with a 6V6gt. As such, the wiring for the adapter is probably going to accommodate that.You are using the adapter for a different concept, i.e., to sub an octal preamp tube for a 9-pin preamp tube--the 6sl7 for the 12ax7. Two things to keep in mind: (1) both tubes are preamp tubes, (2) the 12ax7 is a dual triode tube in a single glass case, the 6sl7 is a single triode tube in a glass case. From (1) if the Behringer preamp is using only one of the 12ax7 triodes you are in like Flynn. If, on the other hand, the Behringer is employing both triodes, you will need two octal tubes to get the job done.
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Continuing: if the Behringer is using a single triode in the 12ax7, all you will likely need to do is to carefully rewire the adapter to make it a preamp tube adapter, not a power tube adapter (if I am correct in my assessment).
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Thanks a lot for the elaborate answer Greentone!
The adapter I bought is actually specifially designed for substituting a 12ax7 with a 6sn7, so I think that isn't causing the problem.
I looked up some wiring schematics of the behringer and i think it is actually using both triodes... Although I'm not to savvy about electronics to be true. So I might be misreading those schematics.
There's one thing i find interesting though: when i Power the Pedal without a Tube it turns on and all the LEDs Light up as they should. But as soon as I plug in the adapter everything turns off.
Guess it doesn't work out then. At least I learned something along the way ?
Paul
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Originally Posted by jasonc
If you compare this with other schematics floating around online, e.g. https://www.tdpri.com/attachments/20...03-jpg.232259/ I have literally zero experience in these things and I can already see differences.
My interest in this is to try building a pedal, but I'd be starting from scratch. Here in the UK it's $70 just to ship a Nocturne JB and you don't see them come up second hand, so I'd like to explore everything else first.
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Thanks for posting the video.
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Originally Posted by xavriley
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Excellent..
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nice video, but I'll need a second Life to find the time to actually watch it.
he mentions a similar Dickerson Amp, on which he has worked some years ago, I found this dickerson on Reverb,
the other day, looks more than promising for that kind of money and it is in Sweden:
Dickerson Amp De Luxe Professional Model 8 ca 1940 | Tip Top | Reverb
needs a 10" speaker ...
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That poor amp deserves better input.
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Thanks for the tip on the Dickerson amp.
I've found a couple of other options in the UK at the moment, sadly all out of my price range at the moment:
* A nice looking Epiphone Electrar £625 Facebook
* Oahu tonemaster £499 Oahu Amplifier 1950 Brown/Cream | London Vintage Guitars of | Reverb
* Magnatone Lap Steel and amp £300-£500 1950s Magnatone lap guitar and amp set, made in USA, ser. no. 9xx2 (another thread here mentions these sound great but they're too quiet to gig)
I'm going to do some experiements with my existing gear first after reading the other thread on dirt pedals in jazz. If anyone in the UK (Guildford area) has an octal amp or Junior Barnyard pedal I'd love to try the real thing though!
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Originally Posted by xavriley
For me, hunting down these very old amps and dealing with their quirks is totally worth it. In 2019 I got a 1946 Zephyr for ? 800€ shipped, and had to invest over the years some 200-300€ more for a carrying case, (rare) tubes a big once-over and routine little revisions. I love it and it gives me an absolutely unique sound, but others may find the whole thing impractical.
The alternatives for that wonderful early jazz sound…
- A Fender tweed (or brownface) clone. Fender became the industry leader quickly simply because his amps of the early 50s were… modern! Solid, reliable, a whole lot more efficient than the octal-based amps of the 30s and 40s. It's not exactly the same sound, but it's a wonderful swing sound. I have a '62 Deluxe and love it. A tweed deluxe clone, used, might get you all you need and then some…
- A "specialized" pedal: I bought a Jr Barnard and had it shipped all the way from Tavo – between price, shipping taxes, it cost me ? 300-400€. Not cheap! It's great but not the same thing as an old amp. I don't regret buying it in the least: it's my indispensable backup. If my old amp acts up (and it has!) I can plug the Barnyard in the PA or in a modern amp and have a good sound. But my sound is a DeArmond FHC through the Zephyr or a Rhythm Chief through the Deluxe.
- A more generic pedal (e.g. American Sounds). I've been much less successful with this route.
Hope this helps a little!
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Originally Posted by xavriley
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octal amps are my love, they really got me into playing electric guitar.
I have posted this pic a lot of times now ... still fits within this thread, my little amp collection, of which 3 are octals.
the '60 GA-200 is a very nice amp, even without them.
'46 Elektra Zephyr Dreadnought with 12" Rola Field-coil
'49 Gibson GA-50
'60 Gibson GA-200
'59 Ampeg M-15
-> I'd safe some money and get a real amp, not just the pedal.
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Filmosound is right. Octal lamps are terrific. I love my octal Fender Pro clone.
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Originally Posted by Greentone
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Originally Posted by Filmosound 621
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it is one fantastic amp for sure, the dear GA-50.
I had a Filmosound Re-issue amp at the time I purchased it, of which I ran with a 1 x 15" Tweed Cab and the famous Altec Lansing 418b speaker.
I bought the GA-50 on the interweb, blind purchase without any test and felt bad after having bought it.
"just another old amp, for so much money" were my thoughts, before it arrived and before I plugged it in.
well, after half a minute with it, I knew the dear Filmosound Amp had to leave ... the GA-50 lives on a different Planet.
Same with the Dreadnought, of which is at a technician at this time, it has the same magic as the GA-50.
The Ampeg M-15 should be in the same ballpark as the early Fender Pro, that Greentone mentioned, 2 x 6L6, octal pre-amp,
single tone and volume knobs only - I read soo many positive things about that amp, before purchasing it - on the interweb, with no test ...
and it doesn't disappoint, it is one of the magic amps out there, that is affordable still.
stock 15" Ampeg speaker is so good, I haven't put the dear Altec in it yet, for test purposes.
Ampeg used octal pre-amp tubes 'til 1964.
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All the TV-front Fender amps are great.
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IDK who Uncle Doug is, but that guy is amazing, and I'd take my amps to him ANY TIME!!
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Hi Xavier,
Next time I organise an in-person workshop, I'll make sure to have my Nocturne Brain El Pescadoro pedal (which is his Jr Barnyard preamp + a reverb section) and Gibson GA-50T amp there so you can come up and give them a try!
Tavo at Nocturne Brain has just released a version 2 of the Jr Barnyard pedal which is $50 cheaper than v.1.
The JR BARNYARD™ Pre-War Hot Preamp (1930's octal tube amp character p – The Nocturne Brain
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I recently discovered octal tube circuits and their definitive sound.
It was like meeting someone for the first time yet feeling like you have known them all your life. Definitely the sound and style I was looking for.
This vintage 47 spectator amp along with a 50s wound Lollar P90 in a non-cutaway 16 inch Campellone archtop are matched up perfectly for my liking and style..
Specials, Prototypes, Seconds
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The Ampeg M15 amp mentioned by filmosound is also a great octal amp.
1979 L5 CES - Sweden ~$7k
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