# Oops.. I did it again..



## Always12AM (Sep 2, 2018)

I bought another National studio 10 (1210) and did it again.









Very nice 1963, 6EU7 for V1 completely original. Sounded like shit.









I was thinking of keeping it all original. I did try to do that. I converted the 6EU7 wiring to 12AX7. Cleaned the living hell out of every point of contact. Added a 3 prong. Build a hidden cap can inside of it. Changed some grid resistors. Reflowed some solder etc.

Still noisy and thin. Cleaned it up a bit and did a little epoxy touch up to a small speaker crack.










I was looking at it and thinking “hmm.. I know one way to eliminate the problem:



















I kept all of the original parts and did a fair amount of recording of where everything goes, but as it stands, I don’t regret doing what I’ve done.

The good news is that some of the original caps are going to have a fun place to hide out until the day I decide to convert it back.










3 position Esquire:
1. Set tone from the gigantic .01 disk and a 25k resistor.

2. Standard .05 Mylar tone and Vol.

3. Bypass tone pot.

That crazy bastard of a treble bleed is an AKI mod treble bleed with a way out of spec NOS Jensen reading about 700pf which is perfect for the AKI mod.









thanks @Alan Small again for putting me on to this treble bleed.

progress on the pine Tele:










She’s shell pink, wet sanded grain still very much present intentionally. The bone nut is installed, first round of French polish on the neck is done. Nitro treatment starting tomorrow. Garage is rigged for the spray.

Update:
Another very kind gesture from @Alan Small and I now have some more suitable material to address the speaker. I lightly doped the outer 2-3cm of the cone and went over the razor thin resin coating to secure it as best as possible.

While I was in there, I decided to go through with shielding the B driver and A grid as well as the V1A coupling cap lead. Should have done that to start I suppose. Also dropped in a dead on spec .047 Blue molded for the V1A coupling cap. It spent 60 years as a ground cap in a Princeton and has now stepped into a more important role. Dead silent operation at all settings. Speaker isn’t doing a death rattle anymore either.


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## Latole (Aug 11, 2020)

Epoxy is not good for speaker repair


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## Always12AM (Sep 2, 2018)

Latole said:


> Epoxy is not good for speaker repair


It was all I had on hand. The rear is about 1cm. Do you have any recommendations in the future?


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## Latole (Aug 11, 2020)

Anything stay soft like silicone, epoxy dry hard.
For a long time repair, best is go to the store to buy the right ( better ) product.

Google speaker repair


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## Alan Small (Dec 30, 2019)

Good stuff Ben....betting you are now able to build and or draw a 5f1 without assistance from google😊

Q Components in Guelph sells a small container of speaker repair goop

Keep on truckin


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## Paul Running (Apr 12, 2020)

Soon you will be able to recall from memory, the pinouts for every audio tube...well done. Your National looks in very good condition.


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## DC23 (Mar 28, 2014)

So cool that people actually know how to do this stuff. It's far beyond me so I just google "amp repair near me"


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## Mark Brown (Jan 4, 2022)

DC23 said:


> So cool that people actually know how to do this stuff. It's far beyond me so I just google "amp repair near me"


That made me laugh really hard mate. I would have saved a lot of time, money and effort if I had have just googled "Amp For Sale" myself. That being said, it is a lot fun tinkering around.

Mr. @Always12AM has shown an outstanding example of turret board wiring. It makes me drool!!

Nice work buddy!

Question. Why are you using 500v Caps off the cathode bypass?? It shouldn't see that kind of voltage right?


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## Paul Running (Apr 12, 2020)

Is it a secret?


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## diyfabtone (Mar 9, 2016)

You can use a cap rated for 5000v if you have the cash and space! What you can't do is use a cap with voltage rating lower than the circuit max, which for cathode bypass is usually anywhere from 2 to 50 volts. Rule of thumb is know the max voltage value and double it for safety.


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## Mark Brown (Jan 4, 2022)

diyfabtone said:


> You can use a cap rated for 5000v if you have the cash and space! What you can't do is use a cap with voltage rating lower than the circuit max, which for cathode bypass is usually anywhere from 2 to 50 volts. Rule of thumb is know the max voltage value and double it for safety.


To be honest I was just wondering if there was a why as I cannot fathom a benefit to it... other than it looks bad ass and that right there is probably justification enough


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## Always12AM (Sep 2, 2018)

Mark Brown said:


> That made me laugh really hard mate. I would have saved a lot of time, money and effort if I had have just googled "Amp For Sale" myself. That being said, it is a lot fun tinkering around.
> 
> Mr. @Always12AM has shown an outstanding example of turret board wiring. It makes me drool!!
> 
> ...


She’s just a massive 25uf / 25V. I don’t know why they make them so large. But they seem to work really well. It was a fun time squeezing 5 or 6 of them into the Princeton circuit lol.

As for the turret board, I highly recommend it! $9 from amplified parts for the board. I will say that there is a lot of potential to do it in a way that creates a lot of headache.

example: I know which components I may want to tinker with in future, so I cut the leads a little shorter so all I have to do is heat and pull. But if this was my first one, I’d have fed the leads way down and around the corner.

The resistors I use for dropping the B+ voltage are massive. And the leads are huge, I chose to wraps the + of the filter caps around the post and wrap some of the leads coming off of them around the post as well and feed the resistor leads deep into the post holes. That creates a bit of a heat sink which is hard to flow solder into.

BUT, I will say, I completed the entire build without solder first and as far as the board goes, I could have likely powered it without solder because of how snug and secure everything is on it. It was also trying to find 6/32 bolts and nuts and find a way to lift the board off the chassis. Would have thought it would have come with mounting hardware.


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## Always12AM (Sep 2, 2018)

Paul Running said:


> Soon you will be able to recall from memory, the pinouts for every audio tube...well done. Your National looks in very good condition.


The National circuit is actually really simple. I kept all of the components on the turrets and just popped them out. I kept all of the original wire used as well. I think modern wall voltages don’t do the little caps and carbon comp resistors any favour. Also both Nationals had a weird way of connecting the cap can to the Rectifier pins. It looks very much like a champ but with different values that create a flatter frequency.


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## player99 (Sep 5, 2019)

Always12AM said:


> The National circuit is actually really simple. I kept all of the components on the turrets and just popped them out. I kept all of the original wire used as well. I think modern wall voltages don’t do the little caps and carbon comp resistors any favour. Also both Nationals had a weird way of connecting the cap can to the Rectifier pins. It looks very much like a champ but with different values that create a flatter frequency.


If you go with solid state amps you'd have more time to hang out by the school in your dirty white panel van.


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## Always12AM (Sep 2, 2018)

player99 said:


> If you go with solid state amps you'd have more time to hang out by the school in your dirty white panel van.


Is that how you lost your virginity? Lol


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## Mark Brown (Jan 4, 2022)

I don't wanna confuse the matter and I don't want you thinking I'm coming on to you or anything.... but the minimalist wiring and excellent pathing on that thing is giving me wood.

I can honestly say I have never spent this much time admiring another man's grid stoppers.


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## Always12AM (Sep 2, 2018)

Mark Brown said:


> I don't wanna confuse the matter and I don't want you thinking I'm coming on to you or anything.... but the minimalist wiring and excellent pathing on that thing is giving me wood.
> 
> I can honestly say I have never spent this much time admiring another man's grid stoppers.


I feel very satisfied having done one like this:










After doing something like this:










They look like visual models of OCD brain VS ADHD. Both of which I am riddled with. Both have benefits. The turret is definitely prettier but harder to service down the road.


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## player99 (Sep 5, 2019)

Always12AM said:


> Is that how you lost your virginity? Lol


Your mom.


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## Mark Brown (Jan 4, 2022)

Always12AM said:


> I feel very satisfied having done one like this:
> 
> View attachment 433741
> 
> ...


I feel like there was some missed opportunity in mine. I was very literal in following the example shown. There are a lot of design elements one could alter, as you have, to really streamline the connection points.

I'm going to have to spend some time reworking it I think. Only for my own sake. 

I really like your work man!

......alright, all the praise is a lie, still just trying to get some private time with your grid stoppers


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## Always12AM (Sep 2, 2018)

Mark Brown said:


> I feel like there was some missed opportunity in mine. I was very literal in following the example shown. There are a lot of design elements one could alter, as you have, to really streamline the connection points.
> 
> I'm going to have to spend some time reworking it I think. Only for my own sake.
> 
> ...


That’s the beauty of doing it yourself! You can go back in a change things as you please!!

I’ve had a lot of time to practice and revisit the design! Just keep experimenting.


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## Always12AM (Sep 2, 2018)

Mark Brown said:


> I feel like there was some missed opportunity in mine. I was very literal in following the example shown. There are a lot of design elements one could alter, as you have, to really streamline the connection points.
> 
> I'm going to have to spend some time reworking it I think. Only for my own sake.
> 
> ...


I appreciate the kind words. I’ve always admired some of the really clean and organized work I’ve seen online in amps and pedals.

Trying to make things organized is a big part of the joy for me. Trial and error is a big part of it as well. I am always tempted to revisit things and tidy them up for visual and technical purposes.


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## Always12AM (Sep 2, 2018)

@Mark Brown updated gut shot.. sorry for what I did to your grid stoppers lol. I needed them to be candy caned a little.


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## Mark Brown (Jan 4, 2022)

So the inevitable question has to be, why did you do this? Was the single line causing some bad voodoo?

Still looking fine, not as fine, but that is subjective. I fell in love with the old but I can accept some change every now and again.


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## Always12AM (Sep 2, 2018)

Mark Brown said:


> So the inevitable question has to be, why did you do this? Was the single line causing some bad voodoo?
> 
> Still looking fine, not as fine, but that is subjective. I fell in love with the old but I can accept some change every now and again.


Any lead that comes from or goes to a grid on V1 or the volume pot are liable to become antennas. In this particular chassis, the volume pis right next to the power section and FAR from the V1. So it called for some shielded wire. As for the grid stoppers. I burnt the heat shrink on the left one from installing both the shielded wire that feeds them and the cap change. So I took them out and added new shrink and decided to twist them to keep then snug and away from that V1A cap. I had to then install a little grounding lug on the V1 post in order to ground the shielding coming from the grids stoppers lead. This could also be done by simply forgoing the posts all together and soldering the lead to the right of the bird and directly into the sleeves of the input jacks and grounding the lead on the common ground of the right one. This would guarantee that they are away from noise making components and lower the chance of a ground loop.

It doesn’t look as pretty, but much like the metal film resistors, low noise takes priority over vintage aesthetic.

I have a .047 cap in both V1A coupling caps on both champs and at one point on the 5E3. I find that it adds a little low end and also accommodates the addition of a bright cap or tone knob in the future. Also, blue molded caps from the 60’s have much fighters tolerances than any cap today even after 60+ years. They sound nice in most cases.


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## nonreverb (Sep 19, 2006)

Always12AM said:


> I have a .047 cap in both V1A coupling caps on both champs and at one point on the 5E3. I find that it adds a little low end and also accommodates the addition of a bright cap or tone knob in the future. Also, blue molded caps from the 60’s have much fighters tolerances than any cap today even after 60+ years. They sound nice in most cases.


Indeed, as do these Erie and Goodall Mylar capacitors.. Introduced in '64 on all Hammond organ models. Unlike the previous wax caps, these barely drift and more than 50 years on, they still are within spec.


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## Always12AM (Sep 2, 2018)

nonreverb said:


> Indeed, as do these Erie and Goodall Mylar capacitors.. Introduced in '64 on all Hammond organ models. Unlike the previous wax caps, these barely drift and more than 50 years on, they still are within spec.
> 
> View attachment 434141


I pulled both Mylar Standard caps from both Nationals and both read within 1% tolerance of their listed spec. It’s impressive.


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## 2N1305 (Nov 2, 2009)

nonreverb said:


> Indeed, as do these Erie and Goodall Mylar capacitors.. Introduced in '64 on all Hammond organ models. Unlike the previous wax caps, these barely drift and more than 50 years on, they still are within spec.
> 
> View attachment 434141


When I think about all the tube television sets that went into land fills, and how many good electronic components they could have donated for amp building... Sad. All those capacitors, resistors, even plain tube sockets. What was once garbage is now treasure.


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## Always12AM (Sep 2, 2018)

2N1305 said:


> When I think about all the tube television sets that went into land fills, and how many good electronic components they could have donated for amp building... Sad. All those capacitors, resistors, even plain tube sockets. What was once garbage is now treasure.


I think about this all the time. Realistically, people in the baby boomer generation had no reason to store their parents tube and transistor equipment. But MANY did.

One of the realities about the suburban phenomenon within Canada is that a lot of people have basements, attics and garages full of stuff that they have no idea what it is or what it’s use is. I feel that over the next decade, a lot of millennials will inherit their grandparents or parents homes and get really good at Etsy and EBay as there is at least some way for them to search and find a perceived value. I plan on buying a LOT of transistors and tubes and building as many amps and pedals and guitars with them as possible.

Right now I’ve been sourcing a lot of really nice Mil Spec stuff from Ukraine. They could use the support right now and they usually have a reasonable price for EL84’s and capacitors and transistors of very high quality. At some point, I’ll be wiring a couple amps to run on their 12AX7 equivalent because they have millions and millions of back stock tubes.

Sadly through, you are right. A lot of very nice equipment and components have been thrown into land fills. My family knows that I’m into this stuff and they keep an eye out for me.


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## 2N1305 (Nov 2, 2009)

Always12AM said:


> A lot of very nice equipment and components have been thrown into land fills. My family knows that I’m into this stuff and they keep an eye out for me.


kewl. With any luck, you'll get a bunch of crappy electrohome console TV sets and a half-dozen eight track players for Christmas. 😆

Nah seriously, good idea on supporting Ukraine. But only if tubes are made in Ukraine (IMO). What is their 12AX7 equivalent?


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## Always12AM (Sep 2, 2018)

2N1305 said:


> kewl. With any luck, you'll get a bunch of crappy electrohome console TV sets and a half-dozen eight track players for Christmas. 😆
> 
> Nah seriously, good idea on supporting Ukraine. But only if tubes are made in Ukraine (IMO). What is their 12AX7 equivalent?


I forget the name, but they require some amp adjustment. I wouldn’t think they are drop in replacements because they have a lot of dissimilar measurements.


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## Always12AM (Sep 2, 2018)

2N1305 said:


> kewl. With any luck, you'll get a bunch of crappy electrohome console TV sets and a half-dozen eight track players for Christmas. 😆
> 
> Nah seriously, good idea on supporting Ukraine. But only if tubes are made in Ukraine (IMO). What is their 12AX7 equivalent?


6N2P. Is the code.


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