Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Esquirefreak on August 10, 2021, 03:23:32 am
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Well, I'm once again in somewhat of a manic state where all I do is amp stuff. I'm on vacation as well, so I'm just trying to keep busy.
This tremolo unit is based on my 6G4 build. As I was tweaking the tremolo a couple of days ago, looking for that sea-sickness-warble. And I gotta say, I really got it right. It's deep and warbly already half way on the intensity dial, but not cutting out when maxed.
I have some transformers on hand. Currently thinking about using a Hammond 370BX, 550CT @ 55mA. Although it might be wise to hold on to that one, since I won't be needing either the 5v winding or the bias tap. I have yet to (possibly with a little help from you guys) decide the values of the dropping resistors in the power section. Another option between the first two B+ nodes would of course be a choke.
This is the first time I design (or rather adapt and draw) something by myself, so please let me down easy. What mistakes did I make? I thought that using the first 2 triodes in parallell would make a useful boost, but I have no idea if it makes any sense.
The leads colors are not an attempt of coding, rather than just a way to see were they all go.
Thankful for input and guidance.
/Max
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I used the Weber WRVBPT PT in my revibe. Small and cheap.
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Yeah, but since I live in Sweden, import fees and taxes make them less inexpensive for me... Unfortunately.
How is my idea looking, apart from that?
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I used a CLC filter before the first B+ node and just determined the values for the B+ droppers experimentally. Your layout looks OK. I didn't check for errors. I suggest a 1M resistor between tip and sleeve of the input jack. The hot/cold switch is not needed since you have an input gain control. You will need a voltage divider on the output to get the signal level back down to instrument level. I linked to my revibe schematic for reference...
http://sluckeyamps.com/revibe/revibe.pdf
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I forgot about the 1M resistor at the input.
Thanks!
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Do you have a schematic of your build you can post?
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No, not really. I pretty much took the trem section from the layout I had for my previous build and adapted it to this one. I could probably try drawing one, but it would take me several days to get it right...
Just got the board populated, except for the under board leads.
/Max
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Do you have a schematic of your build you can post?
Just look at my revibe and pretend the reverb section does not exist.
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No, not really. I pretty much took the trem section from the layout I had for my previous build and adapted it to this one. I could probably try drawing one, but it would take me several days to get it right...
Just got the board populated, except for the under board leads.
/Max
Looking good! But if it were me I'd not do any underboard wires. It's bitchin' to work on afterwards and mistakes are often made.. hard to check that way
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Thanks!
Yeah, that thought has occurred to me, and I might change my mind whether or not to run them under the board :)
Also, I copied the voltage divider from Sluckey's Revibe and added them to my layout. Then I removed the K bias switch and changed the KR on the first gain stage.
/Max
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So glad I discovered this thread. I just built an amp with neither reverb nor vib/trem, and this gives me something else to build!
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As I was studying my own layout I noticed that I made a mistake att the first 22nF cap of the oscillator. Just thought I should mention it before anyone else tries to use this drawing. The cap should (of course) go to the other end of the plate resistor.
I'll correct mine tomorrow when I'm at my shop.
/Max
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Looking good.
That 1 resistor that you have arched around an eyelet, maybe put a piece of isolation striped of of a piece of wire or some shrink wrap on the lead going by the eyelet.
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Yeah, good eye there. I'll get that done by tomorrow as well! :)
/Max