Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 3choplex on January 05, 2011, 02:09:25 pm
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What started out as a bogen challenger conversion has turned into a quasi 5e3 with octal preamp tubes. I’m moving from the original point to point wiring to an eyelet board to make things cleaner and more controllable. This is my first layout and I had some questions about heater placement. I've attached my drawing of the chassis for simplicity. Pink pins are NC inside the tube, I marked heater pins with H.
I know that where signal wires cross the heaters, they should be at right angles. To be able to achieve this with the chassis I am using will mean making the heaters 4-5" longer than they would be using the shortest possible connections. I am assuming that adding all this excess length would still be less problematic than parallel wires, is that right?
Also, does it matter where I connect my heaters to the PT? Can it be in the middle of the series string, or is it better to start at one end and go the whole loop? It seems to me like it would make no difference, but I might as well ask. :wink:
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Also, does it matter where I connect my heaters to the PT? Can it be in the middle of the series string, or is it better to start at one end and go the whole loop? It seems to me like it would make no difference, but I might as well ask. :wink:
Yes, makes no difference and do what you need to go to where you want to go. Looking at what you've got & if it was me, I'd run a twisted pair straight to the pilot then run a twisted pair by the rectifier down along the bottom to the left hitting the power tubes first then up to the preamp tubes while keeping away from the eyelet board. With the tubes where they are you would be better off running all your wires low first to the board, pots, & switches and doing the heaters last where they'd go straight up over everything giving you the most clearance from them.
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add another tag board down by the 7Z4 if you have to.
--ISO
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Is there any reason not to use the 5v heater for just the pilot? The cathode on the 7z4 is separate from the heaters.
Probably I'll be able to answer these question myself in a couple of days. I got an email last night saying the second merlin book is on the way. :grin:
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Go ahead and use the 5 volt winding to power the pilot light. I will be a little dimmer but will work. The 7Z3 is a 6.3 volt rectifier.
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Is there any reason not to use the 5v heater for just the pilot? The cathode on the 7z4 is separate from the heaters.
Probably I'll be able to answer these question myself in a couple of days. I got an email last night saying the second merlin book is on the way. :grin:
You don't need Merlin's books to know this simple & basic info. - it's all right here under your finger tips on this site http://www.el34world.com/charts/fenderservice4.htm
If you are questioning this kind of stuff, you might want to wait to start building anything yet until you've read, learned, and am sure of what you're doing first not after the fact.
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You don't need Merlin's books to know this simple & basic info. - it's all right here under your finger tips on this site http://www.el34world.com/charts/fenderservice4.htm
If you are questioning this kind of stuff, you might want to wait to start building anything yet until you've read, learned, and am sure of what you're doing first not after the fact.
Thanks for the link. Didn't say I had started building it. I'm going to assume positive intent from what you said and the help you provided, but I don't read it that way.
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Sorry. I was in a bit of a hurry at the time & it wasn't meant to offend only help.
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Unlike other sites, it's always best to assume good intent here. Just remember, some of this stuff is being done at 3 or 4 in the morning, or just after waking up. I've looked at a few my posts before and wondered if I actually did that! Also, remember that the snottiest sounding post here will likely have more useful information than the nicest post anywhere else.
I had an aunt that had no clue how to talk without sounding overbearing and just plan mad, especially to boys. She wasn't... she just came across that way. I had another aunt that really was just a snotty bi*ch. It would be hard to tell the difference if you were just reading their words.
Dave
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Sorry for being overly prickly, fellas-- and i do appreciate the help. :smiley:
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Thanks BluesBear, I have to re-read posts a lot to try to make sure that it doesn't come off badly. I can be sarcastic or fun loving and in talking, you'd know instantly there is no ill will. Writing words isn't as easy sometimes to convey this and for me & I need to always be careful with this.
3choplex - no worries. This hobby/business is dangerous sometimes & we have to look out for each other especially if we sense someone that may not have a lot of experience. You may have alot of experience in electronics but not high voltage circuits or who knows? Kinda like the difference between an electrician vs electronics hobbiest. Although they are related, they are very different. If this was a woodworking site, we'd do the same to try to prevent you from cutting off a finger or worse and when working around w/ high voltages the last thing wanted would be the "or worse".
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Hi guys, I don't believe that we can stress the fact enough that we are playing with high voltages and that if we feel that someone may or may not be up to scratch with the does and donots of amp building it can't hurt to point then in the right direction even if it is something simple. I find that sometimes the posting may not be helpful to the person asking the question but helps another. Thanks
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I know 3choplex outside of the context of this forum and can confirm he is adequately frightened of shaking hands with high voltages. :huh: :wink: