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Title: Classic Tone Power Transformer Taps (Which models could we use?) Post by: captainbackfire on July 10, 2012, 05:00:39 AM Hi, I just got the Classic TOne 40-18025 OT for my 50W OTS.
Now I don't know what Power Tranny to use. I've done my research and some ppl seem to have used the Marshall style 40-18033 But They seem to not have the 50-60ish V tap needed for the bias. Am I missing something? WHat do they do and they were able to use these trannies? I've checked all the diagrams of the CLassic Tone trannies but none seem to have the 50v tap. I would appreciate any ideas about this. I just want to hit my first chord on my OTS! Thanks Nick Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: plasticvonaband on July 10, 2012, 08:02:56 PM Nick,
The JTM 45 tranny won't work with the OTS unless you add a separate tranny for bias. The JTM 45 gets its bias voltage via a large capacitor and a resistor network. Also, I believe the relays for the OD and PAB need the 6v tap the stock tranny has to work properly, although I guess you could use the 5v tap that would be used for the tube rectifier's filament in the JTM. I know the Mercury makes a power tranny specifically for the OTS, and Nik is a dealer. I believe you can order through him and the they ship from the US I believe. I haven't seen anyone else offer a tranny with the proper taps, outside of a custom job. Gregg Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: T Wilcox on July 10, 2012, 11:57:56 PM For a 50W OTS with 6l6's I would use the 40-18029
has 355-0-355, 50v bias, 6.3 heater tap and 5v as well ;) Todd Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: captainbackfire on July 11, 2012, 12:00:13 AM Nick, The JTM 45 tranny won't work with the OTS unless you add a separate tranny for bias. The JTM 45 gets its bias voltage via a large capacitor and a resistor network. Also, I believe the relays for the OD and PAB need the 6v tap the stock tranny has to work properly, although I guess you could use the 5v tap that would be used for the tube rectifier's filament in the JTM. I know the Mercury makes a power tranny specifically for the OTS, and Nik is a dealer. I believe you can order through him and the they ship from the US I believe. I haven't seen anyone else offer a tranny with the proper taps, outside of a custom job. Gregg Thanks Gregg! That explains a lot. Yea I actually asked for a quote from Nik for MM's and a combination of his Trannies. I thought Mercury Magnetics isn't the way to go as it was still expensive. Classic Tone stuff seem to be getting a lot of good reviews and have you seen their comparison demo. They're supposed to be built well and just as good as MM. Now I guess its that fun time again of browsing for options. I might settle on Nik's PT. Nick Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: captainbackfire on July 11, 2012, 12:07:13 AM For a 50W OTS with 6l6's I would use the 40-18029 has 355-0-355, 50v bias, 6.3 heater tap and 5v as well ;) Todd Yea I also read some guys use this but I always wondered; the OTS have a 3in x 3+ mounting holes for PT and this Tranny you suggested have a 2 3/4 X 2 7/16 mounting. Also I dont see the BIAS tap on the spec sheet? Thanks for your input. :) Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: T Wilcox on July 11, 2012, 12:14:01 AM When your looking at the spec sheet , below the the diagram where it show the voltage taps it reads where the text is ( Bias 50v Red/grn Red/ylw )
Most if not all the classic tone trannies spec sheets are written this way. Todd Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: T Wilcox on July 11, 2012, 03:09:52 AM When I built my HRM MK2 50 watter I used the 40-18073 xfrmr.
Here, http://www.classictone.net/40-18073.pdf I did have to use a rat tail file and file diagnally inwards at each hole to make the trafo fit the chassis but it was really quick clean and easy. You will have to do this with any of the classictone trannies AFAIK. Hope this helps. Todd Title: Re: Classic Tone Power Transformer Taps (Which models could we use?) Post by: captainbackfire on July 12, 2012, 01:02:12 AM When I built my HRM MK2 50 watter I used the 40-18073 xfrmr. Here, http://www.classictone.net/40-18073.pdf I did have to use a rat tail file and file diagnally inwards at each hole to make the trafo fit the chassis but it was really quick clean and easy. You will have to do this with any of the classictone trannies AFAIK. Hope this helps. Todd Thanks. Definitley this is one of my options. I actually read your post about you using this. Thanks for your help. |