Tube-Town Forum
Technik => Tech-Talk Mesa Boogie => Thema gestartet von: rico am 14.03.2005 16:40
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Hello! Sorry for posting in english, but there are too few topics in english part of the forum. I've got a few questions:
1. Does someone have the second part of "switching matrix" schematic for dual rectifier 3-channel? I have all the sheets, except this one
2. If i build a copy, what power transformer should i use??? From hammonds or some other?? What about choke? Output transformer?
3. Can i substitute those two big blue 220uF 300V capacitors with 220uF 350V or voltage is critical here??????
4. Do i need to have GROUND switch with 0.01uF 1000V capacitor or it's not necesarry?
Thank you!!!!
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1. Does someone have the second part of "switching matrix" schematic for dual rectifier 3-channel? I have all the sheets, except this one
Ya got it.
2. If i build a copy, what power transformer should i use??? From hammonds or some other?? What about choke? Output transformer?
Someone else knows it, i'm sure.
3. Can i substitute those two big blue 220uF 300V capacitors with 220uF 350V or voltage is critical here??????
Yes, you can always substitute Caps by others with a higher voltage rating.
4. Do i need to have GROUND switch with 0.01uF 1000V capacitor or it's not necesarry?
Its not really important to have it. The GND-Switch can reduce hum but it's also a great source for blown fuses and other ugly faults.
Bye
D!RK
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1. Send it please to me, if u got it - here's e-mail - d_konshin@mail.ru
2. I would like to speak with that "someone" :-\
3. I really don' think so ???
4. What exactly this switch does?
Thanks!
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Hi!
I really don' think so
Maybe you don't think so, but life is hard and D!RK is absolutely right!
Good Night,
Joachim
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;D
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Well, that smile gives a REAL support, thanks :-\
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Well, that smile gives a REAL support
The REAL support is D!RKs post in answer #1. Believe it or not. And concerning your question on transformers: here are some really experienced Recto experts on the way, and the time will come, that you will get the final answer. But you opened that thread 8 hours ago, so please exercise some patience ::)
Joachim
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I used the following once, all from Hammond.
372JX Power Transformer
1650T Output Trasformer
193J Joke
I don't know if its the perfect choice but ist works well :D
cu
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3. Can i substitute those two big blue 220uF 300V capacitors with 220uF 350V or voltage is critical here??????
- Yes, you can always substitute Caps by others with a higher voltage rating.
This is of course right as long as you do not want to substitute both Caps with only one Cap.
In this case you need a Cap that is able to manage the full suppply Voltage.
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1.Does those hammond transformers have all te needed wires, or i have to modify it?
2. Shure i mean 2 caps, not one:) I just can't find 220uf 300V caps and i want to substitute them with 220uF 350V caps. If it's okay - i'm happy:)
Thanx!
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Someone? :-\
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Just look at the Datasheets and you will find any Info ;)
mfg :)
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I don't have that much knowledge to determine something from datasheets. If it's not so hard for ya, please, give me some clue.
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Hi rico,
A transformer is not really a complex part and so the datasheets are quite easy to understand, also with low level skills. Nobody knows better than you e.g. which voltages and currents you need for your project. Compare you power requirements with the wiring data of the transformers in the datasheet and that's it.
However, you can't "modify" a transformer.
Joachim
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Shure you can modify a Transformer, but you shouldn't do it ;)
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Shure you can modify a Transformer, but you shouldn't do it
;D ;D ;D
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I just mean, if i build an exact copy, what power transformer (hammond) should i use? Just to match the one on the schematic... ???
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Hi rico,
it's a general problem with the "exact" amp clones. Normally you have no chance to get the original transformers from the manufacturer. And most replacements like the transformers from Hammond, aren't fit the specifications excatly. This is especially critical with the output transformer which is an important part of the sound-shaping.
The power transformer is not that sound-critical. Important for the original sound is the HT voltage which is 350V-0-350V in the Recto. Also you need a filament supply 6x300mA (for 6 12AX7) 4x900mA (for 4 6L6) what sums up to 6,7A. I'm sure this is the reason why killigrew uses the 372JX which has only 300-0-300V but an 8A filament winding. Unfortunately no other Hammond transformer meets the filament specs for the Recto. I think the the 5V winding is needed for supplying the switching matrix.
As I'm not the recto expert I can't decide if the 1650T is a close replacement but if killigrew used it in his amp I'm sure it will also sound great in it.
However, if you need an 100% replacement for the Recto magnetics you will need to order custom made tranformers. Or you look for a supplier who sells Recto-like replacement transformers but I havn't seen one yet.
Regards,
Joachim
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That is a good answer, thank you very much Joachim. I think i go with hammonds, if it's okay - then it's okay, if not - i will try something else.
Thanks!
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There is nothing more to say. Joachim you are so right.
Bye the way. I also use the same parts from hammond and they work quite well so far.
If you want to build an exact copy of the rectifier you can use the 5V winding for the rectifier tube. Thats what i want do to.