Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ledvedder on October 27, 2022, 09:58:18 am
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I'm going to be starting my first 5e3 build soon. I've built several amps before (Ceriatone, Modulus, Headfirst). Mostly Marshall and Matchless circuits. This will be my first Fender circuit.
I decided to go with the kit from Boothill Amps. It was just easier than sourcing all the parts separately, as Boothill's selection seemed good. I added the upgrade for F&T and Mallory caps. I went with Hammond transformers from Antique Electronics Supply, and a cab from Guitar Cabinets Direct.
Now I'm trying to decide if I want to order Rob Robinette's board for his "optimized" layout, or just stick with the basic layout.
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I started some PT wiring tonight.
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I added backup rectifier diodes. I used uf4007 since I had no 1n4007 on hand.
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I may build one of these too. Do you have a schematic you can post? I didn't see any docs on their website when I looked.
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I may build one of these too. Do you have a schematic you can post? I didn't see any docs on their website when I looked.
Boothill just provides a layout diagram, but it's basically like all the other layouts available.
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Some input jack and pot wiring this morning. Not sure if I need to insulate the 1M resistor legs.
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why go the long way instead of the short way?
a tip: keep in mind you can place parts in three dimensions
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why go the long way instead of the short way?
a tip: keep in mind you can place parts in three dimensions
Yup - and you should be careful to avoid the possibility of something grounding out against a bare wire - leave some space. It looks like those jacks might ground when you plug in.
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why go the long way instead of the short way?
a tip: keep in mind you can place parts in three dimensions
I was looking for some good example pics, but couldn't find any. All the layouts I've seen have them going the long way around.
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I was looking for some good example pics, but couldn't find any. All the layouts I've seen have them going the long way around.
https://el34world.com/Hoffman/files/CommonHookups.pdf
http://sluckeyamps.com/64DR/13.jpg
Or, if you will put the 68K resistors on the board like the original 5E3...
http://sluckeyamps.com/5e3/5e3.pdf
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1M resistors redone.
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The tip lug of the top jack needs to be connected to the switch lug of the bottom jack. Do this for both sets of Hi/Lo jacks.
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The tip lug of the top jack needs to be connected to the switch lug of the bottom jack. Do this for both sets of Hi/Lo jacks.
Yep, I'm gonna connect them when I add the grid stoppers.
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1.5K grud stoppers soldered to both power tube sockets.
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Those 1.5K grud stoppers only need to be 1/2 watt.
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Just a heads up on your pot wiring.
If I'm not mistaken, with your pots oriented as they are on the front of your faceplate, when you mount them on the inside of your chassis, your lugs will be pointed to the floor of the chassis.
Not such a big deal with a 5E3, but a royal pain with more complex amps.
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Those 1.5K grud stoppers only need to be 1/2 watt.
That's what came with the kit.
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As far as grounding, what is everyone's preferred method? A ground buss, or wires under the board from point to point?
Also, is it preferred to have 2 separate ground points for preamp and power sections, or a single ground point for everything?
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Those 1.5K grud stoppers only need to be 1/2 watt.
That's what came with the kit.
That surprises me. Can you post the actual Boothill layout you are working from? Scan or take a pic with your phone if you only have a paper copy.
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Here it is.
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That layout clearly shows 1.5K @ 1/2W between 6V6 pins 5 and 6. Just guessing, but I suspect those 1.5K @ 5W are extras to be used as screen resistors if you choose to do so.
Here's a bunch of pics for a Boothill kit build. Step 4 clearly shows 1/2W resistors on the 6V6 sockets.
https://smithtinkertech.wordpress.com/fender-deluxe-5e3-build-part-1/
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That layout clearly shows 1.5K @ 1/2W between 6V6 pins 5 and 6. Just guessing, but I suspect those 1.5K @ 5W are extras to be used as screen resistors if you choose to do so.
Here's a bunch of pics for a Boothill kit build. Step 4 clearly shows 1/2W resistors on the 6V6 sockets.
https://smithtinkertech.wordpress.com/fender-deluxe-5e3-build-part-1/
OK, I contacted Dave to clarify. There are only 4 1.5k resistors in the kit. These 2, and 2 smaller ones (1w?), that would be used on the board.
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Another question. I want to add an impedance selector. Can I just use a 3 way on-on-on toggle switch, or would I need something like this? https://www.tubesandmore.com/products/switch-rotary-impedance-selector-hammond-1600a-series
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The second one is way too many connections, hard to solder.
I'd do the on on on, just 4 terminals. 4, 8, 16 and common. I don't have a link but the one on all my amps are like that. Probably cheaper too.
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That layout clearly shows 1.5K @ 1/2W between 6V6 pins 5 and 6. Just guessing, but I suspect those 1.5K @ 5W are extras to be used as screen resistors if you choose to do so.
Here's a bunch of pics for a Boothill kit build. Step 4 clearly shows 1/2W resistors on the 6V6 sockets.
https://smithtinkertech.wordpress.com/fender-deluxe-5e3-build-part-1/
Dave confirmed the resistors I've used are correct.
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The second one is way too many connections, hard to solder.
I'd do the on on on, just 4 terminals. 4, 8, 16 and common. I don't have a link but the one on all my amps are like that. Probably cheaper too.
So a switch like this will work? https://www.tubesandmore.com/products/switch-carling-mini-toggle-dpdt-3-position-solder-lugs-flatted
I'm planning to do it like the attached image, along with an NFB switch.
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I'm not familiar with that package. I've used these.
https://www.mojotone.com/Mojotone-Impedance-and-Mains-Selector-Switch?srsltid=AR5OiO26_zixZt3eNnBAy4AsaOltrOL7DePQZNYfIQeitLfMDgto89ZLso4
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I've never seen a toggle switch that can be used to select between three impedance taps. The switch in that Rob drawing is a three position slide switch.
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I've never seen a toggle switch that can be used to select between three impedance taps. The switch in that Rob drawing is a three position slide switch.
I often use this one
Jumper between pin 2 & 4
pin 6 is 16 ohm tap
Pin 1 is 8 ohm tap
pin 3 is 4 ohm tap
pin 5 to speaker
https://www.amazon.com/SALECOM-Position-Guitar-Toggle-Switches/dp/B01JDUB4A2/ref=sr_1_1_sspa?crid=30TFJC2SMUXZU&keywords=on%2Bon%2Bon%2Btoggle%2Bswitch&qid=1666995336&qu=eyJxc2MiOiIyLjMyIiwicXNhIjoiMS43MSIsInFzcCI6IjEuNjgifQ%3D%3D&sprefix=on%2Bon%2Bon%2Caps%2C185&sr=8-1-spons&smid=A2TCCY26NO8P0X&th=1
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...Not sure if I need to insulate the 1M resistor legs.
Now sure why you go the long way around. Won't this work? (Maybe even better on the other side of the lugs?
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...Not sure if I need to insulate the 1M resistor legs.
Now sure why you go the long way around. Won't this work? (Maybe even better on the other side of the lugs?
I redid them. See my previous post.
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I often use this one
Jumper between pin 2 & 4
pin 6 is 16 ohm tap
Pin 1 is 8 ohm tap
pin 3 is 4 ohm tap
pin 5 to speaker
https://www.amazon.com/SALECOM-Position-Guitar-Toggle-Switches/dp/B01JDUB4A2/ref=sr_1_1_sspa?crid=30TFJC2SMUXZU&keywords=on%2Bon%2Bon%2Btoggle%2Bswitch&qid=1666995336&qu=eyJxc2MiOiIyLjMyIiwicXNhIjoiMS43MSIsInFzcCI6IjEuNjgifQ%3D%3D&sprefix=on%2Bon%2Bon%2Caps%2C185&sr=8-1-spons&smid=A2TCCY26NO8P0X&th=1
Ahh! Clever.
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Does it matter which lug of the indicator light the wires go to?
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it's just a standard 6vac pilot light, right? ac power doesn't have polarity
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it's just a standard 6vac pilot light, right? ac power doesn't have polarity
It is. I just wanted to make sure because someone on tdpri said it was wired wrong.
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And how about the fuse wiring? Does that matter?
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And how about the fuse wiring? Does that matter?
Yes. Mains hot (should be black) goes to the connector at the end of the fuse.
In other words, when the fuse blows and you open the fuse holder, the live end is at the back of the fuse, not right at your fingers.
Of course you unplug before changing fuses, but your daughter might not.
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And how about the fuse wiring? Does that matter?
Power cord black wire goes to the end of the fuseholder. Side lug connects to power switch. Other side of power switch goes to one PT primary lead. Other PT primary lead goes to the power cord white wire.
http://sluckeyamps.com/misc/bandmaster.pdf
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Ok, I'll have to switch it around. I wired the power switch to the middle lug of the fuse holder. That needs to be moved to the side lug, correct?
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While I'm in the build process, I want to include the mods I'd like to add. I've added several mods to my other builds (switchable gain structure, NFB, depth, etc). I like having the tonal options. I'm definitely adding switchable NFB and the impedance selector. But I'm also considering the switchable bias mod. Has anyone done it? If so, what are your impressions?
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So I'm a week or so behind you on this project. Looking at buying one now. Where are you putting the impedance selector switch? I want to use the rotary one I posted earlier and was wondering if I could use the hole for that external speaker jack? It looks like things are pretty tight on this chassis. Also the spacing between the output jacks is probably too narrow to fit this in one of those holes. Maybe I'll use the switch you're using. Sort of like this from Rob Robinette's site (no feedback switch, had one of those on an 18 watt and it was always off).
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So I'm a week or so behind you on this project. Looking at buying one now. Where are you putting the impedance selector switch? I want to use the rotary one I posted earlier and was wondering if I could use the hole for that external speaker jack? It looks like things are pretty tight on this chassis. Also the spacing between the output jacks is probably too narrow to fit this in one of those holes. Maybe I'll use the switch you're using. Sort of like this from Rob Robinette's site (no feedback switch, had one of those on an 18 watt and it was always off).
I'm honestly not sure yet. Looks like Rob's picture shows it in the speaker jack location. But I'm planning on keeping both speaker jacks.
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So I'm a week or so behind you on this project. Looking at buying one now. Where are you putting the impedance selector switch? I want to use the rotary one I posted earlier and was wondering if I could use the hole for that external speaker jack? It looks like things are pretty tight on this chassis. Also the spacing between the output jacks is probably too narrow to fit this in one of those holes. Maybe I'll use the switch you're using. Sort of like this from Rob Robinette's site (no feedback switch, had one of those on an 18 watt and it was always off).
I'm honestly not sure yet. Looks like Rob's picture shows it in the speaker jack location. But I'm planning on keeping both speaker jacks.
Oh geez, I saw that pic but didn't notice that it shows exactly what I want to do. I'll have to go look at those pics again. Looks like it will work. Mine will be a head so I only need one jack.
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Slowly getting the board populated.
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I'm working out placement for the fixed bias side of the switchable bias. If anyone knows of smaller 50k pots that would work better, please let me know. I think I'm gonna put the switch where the standby switch usually goes. I considered putting the NFB switch there, but figured it wasn't the best idea to run signal from the v2 cathode, all the way over to the switch, then back to the PI. It's unfortunate, since I'd rather have the NFB switch on the panel, instead of inside the cabinet.
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I put a Bourns 25 turn trim pot (https://www.tubesandmore.com/products/trimmer-bourns-3296y-multiturn-top-adjust-pcb-mount) in my Harvard 5F10.
(http://sluckeyamps.com/harvard/h06.jpg)
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I put a Bourns 25 turn trim pot (https://www.tubesandmore.com/products/trimmer-bourns-3296y-multiturn-top-adjust-pcb-mount) in my Harvard 5F10.
(http://sluckeyamps.com/harvard/h06.jpg)
Ohhh, that's interesting! It has the usual 3 lugs needed?
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Test fitting the board before I move on. It seems it'll fit with the input jacks spun the correct way. There's a good 1/2" clearance between the tabs and the turrets/ground bus.
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Can a 25uF cap be used for the fixed bias circuit? I have those on hand, but no 50uF.
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how about this for the fixed bias: https://www.tubesandmore.com/products/trimmer-piher-single-turn-side-adjust-vertical-pcb-mount
25uf should be fine if they're the appropriate voltage rating. i've seen 8uf in big amps, not a puny deluxe
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how about this for the fixed bias: https://www.tubesandmore.com/products/trimmer-piher-single-turn-side-adjust-vertical-pcb-mount
25uf should be fine if they're the appropriate voltage rating. i've seen 8uf in big amps, not a puny deluxe
I grabbed these from Amazon, uxcell 8Pcs 50K Ohm Variable Resistors Single Turn Rotary Carbon Film Taper Potentiometer with Knobs https://a.co/d/02y29LC.
Since the 50uF is a smoothing cap, could I perhaps go larger? I have some 100uF up to 330uF caps on hand.
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Fitting the impedance selector switch. It's tight, but it should work.
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Switch wiring done.
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I like how this bias pot sits on the board.
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Isn't there an advantage to having a 25 turn pot for bias adjustment?
Can you still get the precision that you need with a one turn pot?
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Isn't there an advantage to having a 25 turn pot for bias adjustment?
Can you still get the precision that you need with a one turn pot?
No, and yes.
Don't get me wrong, I love Bourns' trimmers, but these are guitar amps we're talkin' about and you don't 3 decimal point precision.
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Isn't there an advantage to having a 25 turn pot for bias adjustment?
Can you still get the precision that you need with a one turn pot?
I don't see why not. I have a few other amps that use a standard pot for bias adjustment.
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Is it recommended to wire the filaments before or after the board installation and wiring? In all my other builds, which were much larger chassis, I wired the filaments first.
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Is it recommended to wire the filaments before or after the board installation and wiring?
Like everything else in this world, it depends. If I'm putting heater wires on the floor, I'll wire them sooner. If overhead, they are last.
Builders choice, they call it.
Seriously, you have to think about "layers" of components, like planning in 3D, which is exactly what you're doing.
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I started wiring the 50k pot and the switch for the switchable bias mod. This one's pretty tricky to find room.
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Like everything else in this world, it depends. If I'm putting heater wires on the floor, I'll wire them sooner. If overhead, they are last.
My old fingers and eyes find heater wiring the toughest part of wiring an amp. So I do them first so that other stuff is not in the way, and so I can relax and have a beer. But I have also gradually moved away from flying them overhead.
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A wee bit of tube socket wiring.
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I'm curious - it looks like you are going straight in and soldering? I know that works, but I do not trust that and always make a bend to make a mechanical connection. I do not wrap the tube socket lugs - just create some resistance with a +/- 90 degree bend.
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I'm curious - it looks like you are going straight in and soldering? I know that works, but I do not trust that and always make a bend to make a mechanical connection. I do not wrap the tube socket lugs - just create some resistance with a +/- 90 degree bend.
I've always done it this way. This is the 5th amp I've built, and I've never had any issues with the joints.
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I'm curious - it looks like you are going straight in and soldering? I know that works, but I do not trust that and always make a bend to make a mechanical connection. I do not wrap the tube socket lugs - just create some resistance with a +/- 90 degree bend.
I've always done it this way. This is the 5th amp I've built, and I've never had any issues with the joints.
Over time you very well might start to have problems. We've seen it happen more than a few times. Solder is not glue.
You can build your amp any way you like, but, he's trying to give you some insight from experience. Many of us here do agree with him.
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I'm curious - it looks like you are going straight in and soldering? I know that works, but I do not trust that and always make a bend to make a mechanical connection. I do not wrap the tube socket lugs - just create some resistance with a +/- 90 degree bend.
I've always done it this way. This is the 5th amp I've built, and I've never had any issues with the joints.
Over time you very well might start to have problems. We've seen it happen more than a few times. Solder is not glue.
You can build your amp any way you like, but, he's trying to give you some insight from experience. Many of us here do agree with him.
Yes, I understand that. I hope my response didn't come across incorrectly.
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Your fine, no harm, no foul. :icon_biggrin:
Your builds going to be very nice, carry on. :icon_biggrin:
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It's amazing what I got away with on my first two builds. I had no issues at all. Then the third, and most recent one, I had some issues. Zero wiring errors but some bad solder joints. I ended up giving it to an amp tech friend of mine. He sorted it out in short order. I'll be providing the report here on my build thread (he didn't have time to give me all the details, soon). I'll learn from his report for sure. I wanted to get this all done before I started my 5E3 project. Probably getting the Boot hill one as well. Do you think those upgrades for filter and coupling caps are worth it? Adds only about $25.
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It's amazing what I got away with on my first two builds. I had no issues at all. Then the third, and most recent one, I had some issues. Zero wiring errors but some bad solder joints. I ended up giving it to an amp tech friend of mine. He sorted it out in short order. I'll be providing the report here on my build thread (he didn't have time to give me all the details, soon). I'll learn from his report for sure. I wanted to get this all done before I started my 5E3 project. Probably getting the Boot hill one as well. Do you think those upgrades for filter and coupling caps are worth it? Adds only about $25.
Good to hear you're getting things sorted out. I'm not sure if the cap upgrade is worth it, but I figured what the heck. I'll have no way of comparing them. But I trust other builders' opino, since they have much more experience than me.
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It's amazing what I got away with on my first two builds. I had no issues at all. Then the third, and most recent one, I had some issues. Zero wiring errors but some bad solder joints. I ended up giving it to an amp tech friend of mine. He sorted it out in short order. I'll be providing the report here on my build thread (he didn't have time to give me all the details, soon). I'll learn from his report for sure. I wanted to get this all done before I started my 5E3 project. Probably getting the Boot hill one as well. Do you think those upgrades for filter and coupling caps are worth it? Adds only about $25.
Good to hear you're getting things sorted out. I'm not sure if the cap upgrade is worth it, but I figured what the heck. I'll have no way of comparing them. But I trust other builders' opino, since they have much more experience than me.
If you got other builders opinion that's good enough for me. I didn't see mention of that in this thread, or I missed it. The only problem I had with my last build was crackling and buzzing at like 3/4 volume on the clean channel. The high gain channel was perfect. Honestly I probably wouldn't play it that loud on clean anyway but I like things working right. I'm ok making mistakes as long as I learn something. With this hobby the learning never stops.
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And that's exactly what I love about this hobby. I enjoy it, and I've learned a ton. Also, at the end of the day, I have some great amps. that I'm proud to say I made.
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I like these (https://www.ebay.com/itm/233715774226?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=233715774226&targetid=1262779893969&device=c&mktype=&googleloc=9028293&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1262779893969&abcId=9300678&merchantid=101989678&gclid=Cj0KCQjwk5ibBhDqARIsACzmgLQ8OwJQGhTQlnksKY4rwNl7H-FRJ5unzClkLrbfepkWXlHPdZXw5REaAurZEALw_wcB)!
Chassis mount that don't take up much space with a locking shaft.
--Pete
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Things are getting tight!
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I've been going back and forth, trying to decide which mod switched I'd put in place of the standby switch. NFB or bias switch. Then I thought, why not do the pre-PI master volume there? Replacing the 1M resistor with a 1M pot. Then, I'll just put both of the other switches in the chassis.
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NFB switch and bias switch mounted. Bias switch is wired up.
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I think I'm fairly close to complete. Moving on to filament wiring. My favorite part 👎
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Filament wiring completed!
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Ready for first power up! 🤞
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Congrats on getting to this stage. Always a nerve racking moment when you slowly turn up that variac.
BTW - just catching up here. I took no offence on the soldering technique response Yes, I understand that. I hope my response didn't come across incorrectly.
And the reality is I think it depends on the life the amp will live: rattling around in the back of an Econoline van, or residing in the home.
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Congrats on getting to this stage. Always a nerve racking moment when you slowly turn up that variac.
BTW - just catching up here. I took no offence on the soldering technique response Yes, I understand that. I hope my response didn't come across incorrectly.
And the reality is I think it depends on the life the amp will live: rattling around in the back of an Econoline van, or residing in the home.
No worries. No offense taken.
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Deleted.