irv78
Joined: Jun 26, 2009
Posts: 99
Austria
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Posted on Jun 14 2012 01:57 PM
Hi guys, I've recently finished my 6g15 clone. I built this unit for home use because my RI unit is in our band's rehearsal space and I can't be arsed to carry it to and fro.
Well here it is ... totally built from scratch ... cab, board, faceplate ...
Some parts I used ... for the geeks ;)
PT toroidal 30VA (from tube-town.de)
OT Hammond 1760C
Choke Hammond 194A
Chassis Hammond 1444-20 (aluminum)
I'm still having some noise issues. I tried to replicate the ground lift from the RI but it didn't work out so I had to disengage the ground lift for the time being and ground it normally.
— 
Last edited: Jun 14, 2012 13:58:26
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Matt22
Joined: Feb 15, 2007
Posts: 2825
Fredericksburg, Virginia
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Posted on Jun 14 2012 02:08 PM
Awesome job! I'm very impressed! I looked at the power supply side and thought you used Legos to connect the wires!
— Matt "tha Kat" Lentz
Skippy and the Skipjacks: 2018-2020
Skippyandtheskipjacks.net
https://www.facebook.com/skippyandtheskipjacks
Otto and the Ottomans: 2014-2015
The Coconauts surf band: 2009-2014
www.theamazingcoconauts.com
Group Captain and the Mandrakes 2013
http://www.gcmband.com/
The Surfside IV: 2002-2005, 2008-2009
the Del-Vamps: 1992-1999, 2006-2007
http://www.dblcrown.com/delvamps.html
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tubeswell
Joined: Sep 24, 2011
Posts: 1424
Wellington, NZ
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Posted on Jun 14 2012 02:56 PM
B'yootiful job!
The RI ground-return elevation is a modern contrivance which is damn fidgity to implement. The brass grounding plate method works fine in most cases.
— He who dies with the most tubes... wins
Surf Daddies
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LeeVanCleef
Joined: Oct 05, 2011
Posts: 744
France
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Posted on Jun 14 2012 04:10 PM
So you built it because you didn't want to bother carrying your RI tank??!
And from scratch??!
You're my new hero 
— Old punks never die... They just become surf rockers.
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cambeezy
Joined: Jun 26, 2007
Posts: 399
Cleveland, Ohio
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Posted on Jun 14 2012 04:25 PM
Nice build Irv! Congrats!
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Admiral_Fishwich
Joined: Nov 21, 2010
Posts: 118
surfin' Lake Ontario
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Posted on Jun 14 2012 08:51 PM
Looks great!!
— the Undead Bureaucrats
http://www.facebook.com/TheUndeadBureaucrats
The Rum Sweats
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SanchoPansen
Joined: Jan 04, 2011
Posts: 1588
Berlin L-Berg
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Posted on Jun 15 2012 04:55 AM
Impressive! Let us hear it please 
— The Hicadoolas
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irv78
Joined: Jun 26, 2009
Posts: 99
Austria
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Posted on Jun 15 2012 05:31 AM
Thanks, everybody! 
Clips will follow as soon as the noise issue is resolved!
—
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ludobag
Joined: Jun 05, 2010
Posts: 620
at south of
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Posted on Jun 15 2012 05:51 AM
wants
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vintagesurfdude
Joined: Nov 28, 2011
Posts: 795
Prescott Valley, AZ
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Posted on Jun 15 2012 12:04 PM
Cool.... 
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rotnroby
Joined: Mar 31, 2010
Posts: 877
Santa Barbara Ca... in the 805
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Posted on Jun 15 2012 12:11 PM
Amazing job man!!! What pan did you end up using?
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irv78
Joined: Jun 26, 2009
Posts: 99
Austria
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Posted on Jun 15 2012 12:33 PM
rotnroby wrote:
What pan did you end up using?
ATM I'm using my second favorite pan in it (current production accutronics/belton). My favorite pan is in the RI unit (a '66 Gibbs).
But there is another vintage Gibbs on its way over the great pond
—
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rotnroby
Joined: Mar 31, 2010
Posts: 877
Santa Barbara Ca... in the 805
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Posted on Jun 15 2012 01:08 PM
I have a 64 Fender unit and it uses the Gibbs aka Hammond unit.. Not as drippy as my Gomez G-spring as Dario was using the older Accutronics ..
I'm convinced that the older Accutronice are the best! "For Me" that is..
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Bob_Kennedy
Joined: Feb 27, 2012
Posts: 316
Mesa, AZ.
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Posted on Jun 15 2012 02:29 PM
Looks great! I wouldn't be able to tell it apart from a Fender unit from the outside. Beautiful. The "guts" look great too!
— Otto & The Ottomans
Kennedy Custom Guitars
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thesjkexperience
Joined: Jul 02, 2009
Posts: 56
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Posted on Jun 16 2012 10:32 PM
Wow!!!! Simply amazing and so, so pretty!
Would you consider a reverb unit easier, or the same, difficulty to build as a brown or blackface amp?
— Owner of Gunbarrel Custom Guitars!
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busse
Joined: Jun 17, 2012
Posts: 13
Sweden
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Posted on Jun 17 2012 05:23 AM
Looking wery good!
I'm planing to build a reverb based on the 6G15 and I see that you have used a main transformer from tube-town. Is it this the main transformer that you have used? http://www.tube-town.net/ttstore/product_info.php/language/en/info/p2192_Ringkern-Netztrafo-30VA.html What voltage do you have on B+?
I'm concider which of tube-town transformen I shall use, the 30VA that give 200V of the 50VA that give 250V?
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irv78
Joined: Jun 26, 2009
Posts: 99
Austria
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Posted on Jun 17 2012 01:15 PM
thesjkexperience wrote:
Would you consider a reverb unit easier, or the same, difficulty to build as a brown or blackface amp?
A reverb unit is slightly more complex than a Tweed Champ - which is one of the most basic amp designs. So I think it is save to say a reverb unit is far easier to build than any black- or brownface amp.
busse wrote:
I'm concider which of tube-town transformen I shall use, the 30VA that give 200V of the 50VA that give 250V?
Yes, the 30VA is exactly the transformer I used (OMG it's so CHEAP )
I get 270V after the choke (with full-wave rectification) - this is about 10% under the 'perfect' voltages of the schematic. With the 50VA you will definitely get voltages that are over the 'perfect' voltages but still within the generous +/-20% fender tolerances.
I think it doesn't matter too much wich one you choose - I was just more comfortable with the slightly lower voltages. I bought most of the parts at tube-town - their prices for the Hammond transformers are pretty good too.
I can strongly recommend the Hammond 1760C as reverb/output-transformer. with the 8 ohm tap you have a perfect match for the 6K6 tube with 7000 ohms. I think spec-wise this is as close as you can get to the original 125A12A transformer.
—
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LoeD
Joined: Feb 29, 2012
Posts: 310
Germany
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Posted on Jun 18 2012 12:50 AM
Hi, I´m the other guy that just finished his 6G15 clone...
I used the 50VA TubeTown PT and I get 350V B+.
My OT is a hammond 125BSE.
The 6K6 has a impedance of 9000 Ohms @ 315V. As I get 350V 10kOhms primary are very close. The Hammond OT has taps for 10k primary to 8 OHm sec. which is perfect imho. The OT also enables me to try different primary impedance (5k),so I have the opportunity to test a mismatch at the OT just to see or hear how it sounds. And the 125BSE is slightly cheaper than the 1760C
And for the grounding issue, I used a auto groundlift similar to the one in the RI that I used in an other amp before it works perfect, no hum at all. I used a ground bus and isolated jacks.
please see the other tube reverb thread for details, there´s the layout drawing...
— here comes the WEST SAMOA SURFER LEAGUE
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irv78
Joined: Jun 26, 2009
Posts: 99
Austria
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Posted on Jun 18 2012 02:15 AM
My output transformer choice based mainly on this information I've found.
This is basically all information I found about the 125A12A transformer.
archive-ampage-org
http://archive.ampage.org/articles/4/gagd/241821/Re_Reverb_Transformer_Impedance_My_measurements.html
Part number 125A12A as used in the 6G15.
Turns ratio 30.15:1
Calculated impedance ratio 909:1
Therefore, assuming an 8 ohm reverb tank input transducer, the primary
impedance would be 7,272 ohms.
I'm sure having the exact transformer ratio doesn't matter too much in this application, because the variance of the reverb pan's input transducers is huge. In the end you'll just have to find the pan that matches the transformer to get the best sound of your unit.
—
Last edited: Jun 18, 2012 02:29:12
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busse
Joined: Jun 17, 2012
Posts: 13
Sweden
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Posted on Jun 18 2012 08:59 AM
Thanks for your answers, so the both tube-town trafsformers will work in this reverb. I you use a 50VA and get 350V on B+ I think it must be possible to lower th B+ with a resistor i series with the B+, on the other hand I think it mabye should be possible to run the 30VA on it's 220V tap and got around 5% higher B+ with out getting to high voltage to the heaters.
What about the OT, is there any OT that will work well with both 6K6 and 6V6? I'm not building a clone so theres no problem if I must have a switch to change impedance on the OT when I change between 6K6 and 6V6 tubes.
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