Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: bigOandrew on September 29, 2021, 09:29:24 am
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Hello Lords of the Solder,
I'm just another guy (CZ this time) trying to rebuild some DeVille because of burned out pcb. I'd like to reuse chassis, trafos, speakers..and tubes..
My starting point is here: https://el34world.com/charts/Schematics/files/Fender/Fender_hotrod_deville.pdf (https://el34world.com/charts/Schematics/files/Fender/Fender_hotrod_deville.pdf).
Aaand my question(s) is attached as png..
Very very very kind regards
Ondra
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Answered in kind. :icon_biggrin:
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THANK YOU FOR YOUR REPLYYY!!!
Anyway - please let me to check my proper understanding:
1) Missing CP17 at Export trafo WD is like Fender's overlook then?
2) What am I supposed to do with that little DC power stage for solidstates?
I would just solder that extra brown tap to eyelet...
3) The rest of my "custom" adjustments are legit? I guess my intention is obvious..
Thank you. Thank you. Thank you.
Yours
Alice in Wonderland
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Anyway - please let me to check my proper understanding:
1) Missing CP17 at Export trafo WD is like Fender's overlook then? yes
2) What am I supposed to do with that little DC power stage for solidstates? delete it
I would just solder that extra brown tap to eyelet... tape the end and tuck out of the way
3) The rest of my "custom" adjustments are legit? I guess my intention is obvious.. yes,except NORMAL BRIGHT swith will not work as drawn. To fix, remove R102 and ground lug 1 of the switch.
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I've already started some wiring such as TMB stack directly on pots etc (-gonna send pics later). Nevertheless I'd like to consult last version of my "HRDV on diet" - 'll be greatfull for any comments!!!
PS: I wish that somebody else will find this helpfull..
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Just sharing..
https://drive.google.com/folderview?id=1PCU2pWgjEvzAfJ8Vdr5d4VUJfGdaKk3A (https://drive.google.com/folderview?id=1PCU2pWgjEvzAfJ8Vdr5d4VUJfGdaKk3A)
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Circuit boards? Who needs any circuit boards! :laugh:
Your rebuild is fine business!
How soon we forget the crafts from the past. This was once the norm of all electronics.
Keep up the good work!
Thank you for sharing your progress. Looking forward to seeing the finished project.
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On your pictures, I see a lot of non-isolated and unattached connections to terminals. This is not a safe and reliable way to make a assembly.
Just few of them;
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I used either inexpensive terminal strips .......... OR use left over turret board material strips to set up the filter caps for the B+ voltages. They are well above the chassis and I don't have to worry about voltage hitting ground/chassis. This seems a reasonably safe approach to me.
This approach allows me to still see the PT wiring and follow where that goes to.
I would be very nervous having the filter caps sitting on the chassis even in "insulated" by silicone or a glue gun.
with respect, Tubenit
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This is not a safe assembly, it is rather dangerous and not of solid construction.
However, there is no lack of photos of amp assembly on the web
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i'll be very curious how you handle the bias circuit. Very bizarre transformer with a 28v-0-28v winding.
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On your pictures, I see a lot of non-isolated and unattached connections to terminals. This is not a safe and reliable way to make a assembly.
Thank you Latole, such remarks, as this yours one, are the worthwhile ones. Anyway I'd like to note, that those marked ("arrowed") connections are about 30 mm (1.2 '') above the chassis - I'd guess you missed the spatial arrangement image, because there is no side, nor in level picture.. Is this actuality changing your mind somehow..?
i'll be very curious how you handle the bias circuit. Very bizarre transformer with a 28v-0-28v winding.
I don't get it.
Moreover I'm attaching collage of pictures of my build to keep them for other future readers.
And startler:
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On your pictures, I see a lot of non-isolated and unattached connections to terminals. This is not a safe and reliable way to make a assembly.
Thank you Latole, such remarks, as this yours one, are the worthwhile ones. Anyway I'd like to note, that those marked ("arrowed") connections are about 30 mm (1.2 '') above the chassis - I'd guess you missed the spatial arrangement image, because there is no side, nor in level picture.. Is this actuality changing your mind somehow..?
No I did not missed spatial arrangements images.
This not the right and safe way to built a amp.
You must use eyelet or turret board or terminal lugs. Sorry, there is no other way.
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I guess the following is against forum rules but need to ventilate: Dear Latole, I honestly hate you.. your stubborness about safety drived me crazy thus after a bit of sucking in some knowledge I'd label myself as mad prof..
And here I am with new schematic on the table and begging for your suggestions and respectable opinions.. let's rebuild that rebuild..
Humbly thank you in advance. Very kind regards
The Biggest O.
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Does this "new" schematic represent what you currently have ............... OR what you are aiming to change it into & you're simply wanting comments on this change?
Do you have another 9 pin socket and/or a dual triode available? If so, there are endless choices of well known amps available for you to copy their preamps.
OR .......... you could consider something different and a little more off the beaten path?
With respect, Tubenit
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Dear tubenit, thank you for your interest, I'll answer point by point:
Does this "new" schematic represent what you currently have ............... OR what you are aiming to change it into & you're simply wanting comments on this change?
My current build is (according to this thread) just not build the safe way, hence this "new" schematic was posted to be exposed to public estimation - yeah, wanna a lot of comments..
Do you have another 9 pin socket and/or a dual triode available? If so, there are endless choices of well known amps available for you to copy their preamps.
Well, yes, I have, but, as written, there are endless choices and - I don't like choices..I like simplicity and like to understand things..and I'd like to build something ..ehm.. meaningfull(?)
I pray for that my czenglish (czech+english) is understandable..
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No I did not missed spatial arrangements images.
This not the right and safe way to built a amp.
You must use eyelet or turret board or terminal lugs. Sorry, there is no other way.
....It's a new year and Covid19 (or is it Covid22 ??) is raging. I don't entirely agree.
I have designed and built tube preamps using quality Nema G10/FR4 Fibrelass PCBs. I have used Doug's (quality) turret boards and built very successful amps.
I have also used Tagboards for prototypes and final builds (https://www.evatco.com.au/36-way-tag-board-2-rows-of-18)
I personally avoid Phenolic resin PCBs (or Boards for Turrets) as I find Heat plays havoc with Phenolic Resin boards.
Assuming bigOandrew that you have maintained integrity with your mains wiring/earthing/switches/connectors, I see no problems with your current build AS LONG AS IT AS A PROTOTYPE!! :wink:
Once you have developed your final Schematic (as encouraged by Tubenit), I would use use whatever is most convenient (Turret/eyelet or Tagboard) to build the final version. (Custom PCBs can be expensive) Tubenit's Exodus is a good example of custom turret use :thumbsup:.
For your own interest, it would be good to finish off the amplifier with neat Robust component mountings so that you can get many enjoyable years from your amp.
Keep up the good development/work :laugh:
Kind regards
Mirek
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Latole..?
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Ok now this looks much safer than HV floating near the chassis!!
The thing is, if the amp is transported or moved around often, there is a risk of HV points touch the chassis, and it is where the strings of a guitar are connected !! :blob8:
A safe build is very important, not only for the technician but for the player as well.
Latole will show up !
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:thumbsup:
A safe build is very important, not only for the technician but for the player as well.
+1 with Uki (in this case, the builder)
Regards
Mirek