Q418C - Mike builds an amp and tries not to die // 5E3 build now in progress!

stickyfiddle

A little more done last night. All wiring now done on valve sockets and pots. The main lead between V2 and the volume pots is shielded to reduce noise, which was a bit finicky to do, but I got there in the end. 

For this his bit I also realised a bit more light would be useful, so my trust “Ikeapoise” came in very handy



Only a handful of solder joints to go, then testing...

But at this point I was tired and Max was trying to get involved, so I went to bed. More today/tomorrow, work and drum-lesson permitting? Hopefully! 

roundthebend

Lovely stuff. You're inspiring me to have a go too.

NorthernPaul

Brilliant thread, just read through it all, looks like you're doing a grand job!

stickyfiddle

Cheers all. It's been really enjoyable. Not in an adrenaline inducing sort of way, but really interesting, and I've always liked building stuff, so it's all good. 

I now massively appreciate the hours that go into handwired amps compared to PCB ones. Even when you do it for a living with a permanent setup it's careful, slow work. 

Hopefully will get it finished tonight, work permitting, then start planning the next one - a Deluxe Reverb is not looking quite so complex now. Obviously it's got more components, but the individual parts aren't any more difficult. 

I wonder if anyone does a version that's just the vibrato side with switchable bright cap, in the form of a kit? I suspect not

roberty

stickyfiddle said:

Cheers all. It's been really enjoyable. Not in an adrenaline inducing sort of way, but really interesting, and I've always liked building stuff, so it's all good. 

I now massively appreciate the hours that go into handwired amps compared to PCB ones. Even when you do it for a living with a permanent setup it's careful, slow work. 

Hopefully will get it finished tonight, work permitting, then start planning the next one - a Deluxe Reverb is not looking quite so complex now. Obviously it's got more components, but the individual parts aren't any more difficult. 

I wonder if anyone does a version that's just the vibrato side with switchable bright cap, in the form of a kit? I suspect not

The normal side of the Deluxe Reverb takes distortion pedals really well. I never anticipated that I'd use that side but it's great for punky rock stuff and makes the amp super versatile

stickyfiddle

roberty said:

stickyfiddle said:

Cheers all. It's been really enjoyable. Not in an adrenaline inducing sort of way, but really interesting, and I've always liked building stuff, so it's all good. 

I now massively appreciate the hours that go into handwired amps compared to PCB ones. Even when you do it for a living with a permanent setup it's careful, slow work. 

Hopefully will get it finished tonight, work permitting, then start planning the next one - a Deluxe Reverb is not looking quite so complex now. Obviously it's got more components, but the individual parts aren't any more difficult. 

I wonder if anyone does a version that's just the vibrato side with switchable bright cap, in the form of a kit? I suspect not

The normal side of the Deluxe Reverb takes distortion pedals really well. I never anticipated that I'd use that side but it's great for punky rock stuff and makes the amp super versatile

Yeah, I like both channels, I'd just ideally want the option to plug into a single input, then switch between them, and use reverb (and to a lesser extent, trem) whenever I wanted. I'm not sure anyone builds an amp that does exactly that (never mind that in kit form!). And I'd put power scaling in as well because I don't know why anyone wouldn't these days.

I suspect I'm getting idea above my station at this point - I haven't even got this one working yet... But if it works first time I might find myself getting a bit cocky  

stickyfiddle

Tonights efforts... I had to remove the lower jack sockets to actually get them wired neatly, but there was just enough room to get them out and in again with wires on.



Which means I'm done! If I haven't done something wrong, at least. 

Final solder joint. Actually a little messy, but it should work fine



And the whole thing done. Reasonably neat. Not like a Hiwatt or something, but I'm happy with it for a first try. The proof of course is in the pudding. Testing starts on Friday. Lots of voltages to check, then if everything looks right I'll actually put a signal through it and see if it sounds good! 

*Then* I'll take it apart again and add the VRM circuit, which will likely go in place of the standby switch, as I'll rarely use that at home and an original one wouldn't have had one anyway




And one last picture for the evening: Max in his natural environment, scrabbling in any box he can find, looking for loose bits of wire or string to play with....

roberty

Looking great man, very nice work. I can appreciate how fiddly it is from those close ups

grappagreen

I'm starting to get excited now.. just one point; if you've done everything right it won't sound good - it will sound amazing!! That I can pretty much guarantee

Si

stickyfiddle

Done! 

Full post in the morning as I've worked 13 days straight and have lurgy. But it worked first time, it sounds good, and I didn't die  

merlin

Hooraay...... Please post extensive and high quality sound files.. .. 

stickyfiddle

merlin said:

Hooraay...... Please post extensive and high quality sound files.. .. 

 I might even do a video! Though it's still loud, even with the VRM on minimum! Might need an attenuator on top. 

But it does sound really good. The Alnico Blue is lovely, even if it's making the loudness worse.

stickyfiddle

Picture time

Speaker. Blue. I've heard these used by a number of players I love, and wanted one for ages, but never actually played one.




Quickly whipped up a bit of speaker cable from a stripped-down bit of mains flex. This whole thing got a bit of heat-shrink for strain relief, but not expecting it to need much as it won't be moved around.



Testing time. First the power transformer, just to double check, and then the rectifier to ensure that's sending the right voltage to the right places. Black clipped firmly to ground, one hand outside the amp resting on the table, the other hand very carefully probing with the red cable. No smoke, no shocks, no death! 



Everything was ok, so time for all the valves and a speaker. That all seemed ok, so time to plug something in..

Excuse the mess...! 



Again, all good, so time to mount in the cabinet. 




All finished and working! Note the Standby switch is a switched pot for the VRM - acts as a regular standby switch, and then turns the voltage up as you turn the knob clockwise.

stickyfiddle

Now a question and request from the more knowledgable amp-tech folks here.... 

This thing doesn't sound anywhere *near* as dirty as I would expect based on youtube clips. Plugged into the Bright side, with both volumes on 3 and tone at 9, I'd expect a chunky bit of dirt. Not JCM800 stuff, but a dirty tweed sound. This is barely breaking up at that point, and that's really the dirtiest it gets. VRM is changing the overall volume but not tone and dirt levels, so I'm confident that's fine.

When checking voltages, the only one outside ±10% of spec was the grid voltage on pin 7 of V2 - my diagrams say a target of 18V, and it's between 6V and 7V here. I assume that is the main cause, but I can't see anything wrong in the wiring, which has already been triple-checked for correctness and continuity (and non-continuity!) as applicable.

Could it just be a slightly weak valve in V1? Is there anything obvious that would give this result? 

Tagging the obvious folks that spring to mind @ICBM @ecc83 @jpfamps @RiftAmps...

FWIW it actually sounds excellent and I like Tweedy cleans more than dirt, but I'd like to understand the cause! Any ideas??

stickyfiddle

After some more reading, it seems that cheapie multimeters are a common cause of a false reading on pin7/V2. Mine is a $5 Maplins job from at least a decade ago, so maybe time to get something a bit better for general use as well as just this project. In any case, it sounds like its possible (even likely?) that everything in my build is actually spot on and I'm just not hitting it with hot enough pickups? Or that in conjunction with a V1 that isn't veyr pokey? 

Given it sounds great in a chimy edge-of-clean way I'm perfectly happy with it, as long as I'm not risking shit tube life or killing a transformer! 

Thoughts welcomed!?

Clips later, maybe..?  

springhead

Single coils or humbuckers?  I built a 5E3 a year ago, with variable HT and a Celestion Blue.  With a Strat I'd expect some breakup around 3, just starting to sound a bit chewy.  Turning your other channel to 9 will clean that up a bit, but you should be hearing some warmth at that point. To me around that point it sounds like "why would I want to plug a Strat into anything else?".  Glorious.

With humbuckers or P90's you should be getting some dirt around there.  Certainly by 4-5 it'll be mucky. 

What are you using in V1, 12AY7?  That's what I have, have tried 2 or 3 different types. They all have similar gain, varying amounts of hiss and slight tonal changes.

Try swapping your V1 and V2 valves for others if you have them. 

Are all your measurments good?  350 ish on the 6V6 anodes and around 20V on the cathodes?  Cathode bypass cap's definitely soldered firmly in place on V1 and V2a?  Not got a wrong resistor value somewhere?

stickyfiddle

Yup, 12AY7 in V1. There is a little dirty, but I'd describe as the crunchy end of clean (rather than an angry Neil Young) with both volumes on 3. Though as I say, it's a really good sound, so I don't mind keeping it like this if I can work out how I've modded it, even if it was unintentional!

I have spare 12AX7s, so can try popping one of those in V1 & V2 in turn. 

My other measurements were all fine. Each one measured twice and ok based on this diagram - http://www.trinityamps.com/docs/TweedLayout18.pdf. The only voltages that were >5% out were the plate voltages on V1, which both read at 110V rather than the quoted 130V. Both all the 6v6 voltages were spot on.

Resistors were all checked before and during installation, though maybe it's worth me double-checking again with them in-situ.

springhead

Crunchy clean at 3 is probably about right.  Angry Neil is higher up.  You should find from about 5 onwards it doesn't get any louder, just more like Mr Young.

stickyfiddle

springhead said:

Crunchy clean at 3 is probably about right.  Angry Neil is higher up.  You should find from about 5 onwards it doesn't get any louder, just more like Mr Young.

It may well be exactly as it should be - even with the VRM right down I can't wind it up in my apartment, so I can't tell exactly how dirty it gets. It's certainly cleaner than some other demos I've seen but maybe they have much hotter pickups than me. I’ve tried with vintage flavoured hum buckets and some TV Classics so far.

 I'll be able to tell once I've got myself some additional form of attenuation.

What I can say is that it sounds fabulous at that chimey point, and I should have bought a Celestion Blue frickin years ago  

stickyfiddle

In semi-related news, this vintage Springsteen live set was the soundtrack to most of the build. Absolutely cracking