Dynaco ST70 Tube Amp Restoration: Populating the Board #1

[@6StringPassion.]

Not boring. Great. I have an ST70 that I need to repair/restore.

[@SkunkieDesignsElectronics]

It’s a fun project to work on.

[@RobertKohut]

Before I did any "serious" soldering I bought several Chinese kits like a small clock and the such. Then after many solder joints on the "who cares" kits I tackled some "important" kits and was very successful.

[@yellow_noise3]

It is OCD indeed, which I love! One thing however. Bending the resistor leads prior to soldering make difficult to repair if needed to resolder. I am personaly not bending. Also good habit is to resolder after lead cut. Just reheat for a moment, to release all mechanical tension...

[@rickg8015]

Great stuff, Stephe.. Please do upgrade the power transformer, if/when you can..

[@Luckiestmanalive-bb1mi]

I love the disclaimer/health warning but I just got the popcorn out!

[@hugobloemers4425]

Hi Stephe, people can see instantly that you are experienced with soldering, and also PCBs. I also have the same OCD putting the resisters all in the same orientation. As a matter of personal taste, I always prefer green PCBs that give that vintage look. But I understand the look you are after.

[@WayneHatfieldBrotherRidge]

Good morning 🌞😊.

[@frankgeeraerts6243]

I solder the resistors first also...keeping the resistors off the board should be standard practice. I always clean the board ( and the solder points ) before starting to solder.... As you mentionned it , use GOOD quality solder. ( I use always lsolder with lead , never leadfree wathcreate a ever they may say ..) sometimes two resistors of the SAME value are used in parallel , in that case I mount them ( tête-beche ) that bmeans inversed on to another ....as most resistors values are made with laser spiraling this method cancels the small residual generated inductance . Having avery small amount of solder on the tip of the soldering iron creates a heat bridge between the soldering prts and does reduce the soldering time of the soldering and solder flows better and faster. Beware when cutting off the lead after soldering , sometimes they fly and can cause damage to your eyes..it happens . I keep some of the longer cut offs , they can be used when you need to bridge between some solder points... Watching soldering has a calming effect and while drinking a coffe or else it is entertaining indeed . Thanks for the upload.

[@g-train9372]

Love it! Right up my alley Steph. Thinking of purchasing an ST70 kit. Looking forward to seeing the test results.

[@SkunkieDesignsElectronics]

This could be my new "$1000 price point" amplifier!

[@holamateo]

@@SkunkieDesignsElectronics Would you be open to doing a video elaborating on what you love this amp? I’m most curious how your EL34 amp compares with the ST-70 from a sound signature point of view.

[@SkunkieDesignsElectronics]

Pretty sure a SE EL34 amp is going to sound very different from a PP one.

[@MojoMedicineMan]

👍

[@shawnlaikan9000]

Enjoying your videos! I've been following your channel for the tube amp/preamp/phono amp builds. Would love to see your thoughts on their SP14 preamp. Its a 6sn7 Aikido based preamp, I'm sure you've seen it on their website. I've built one (a little different from what's published), I think it sounds great. Interested in their ST-120

[@insurrectionindustries1706]

You may want to get some 3-3.5K resistors as possible replacements for the 7K ones, may come in handy down the road😉

[@SkunkieDesignsElectronics]

I have a bazillion resistors here :)

[@NosEL34]

👍👍

[@nbramaputra]

You cant avoid print,if working on electronic,i prefere the point to point, i think you have manny tecnics to fix,Wat scares me ,-to repair on the print bords. How do you remove tube soclets?

[@SkunkieDesignsElectronics]

Cut the legs and remove them. I build all my stuff point to point but it's a lot harder than populating a PC board. I don't mind signal tubes on a PC board, I think output tubes get too hot to put them on a board.

[@brycejeannotte7699]

I don't know the condition of your chokes, but often the originals are damaged and should be replaced. They would get hot and all of the wax would melt out. They are not expensive to replace, but they are a bit of a pain to get to.

[@SkunkieDesignsElectronics]

It measures OK so I'm gonna give it a whirl :)