My first 5e3 build

[Ledvedder]

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.

[Ledvedder]

Fitting the impedance selector switch. It's tight, but it should work.

[Ledvedder]

Switch wiring done.

[Ledvedder]

I like how this bias pot sits on the board.

[scstill]

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?

[acheld]

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.   

[Ledvedder]

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.

[Ledvedder]

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.

[acheld]

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.

[Ledvedder]

I started wiring the 50k pot and the switch for the switchable bias mod. This one's pretty tricky to find room.

[bmccowan]

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.

[Ledvedder]

A wee bit of tube socket wiring.

[bmccowan]

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.

[Ledvedder]

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.

[Willabe]

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.

[Ledvedder]

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.

[Willabe]

Your fine, no harm, no foul.   

Your builds going to be very nice, carry on. 

[JPK]

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.

[Ledvedder]

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.

[JPK]

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.

[Ledvedder]

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.

[DummyLoad]

I like these!

Chassis mount that don't take up much space with a locking shaft. 


--Pete

[Ledvedder]

Things are getting tight!

[Ledvedder]

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.

[Ledvedder]

NFB switch and bias switch mounted. Bias switch is wired up.

[Ledvedder]

I think I'm fairly close to complete. Moving on to filament wiring. My favorite part 👎

[Ledvedder]

Filament wiring completed!

[Ledvedder]

Ready for first power up! 🤞

[bmccowan]

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.

[Ledvedder]

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.

[Ledvedder]

Deleted.