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ccdowenye

Finally pulling the trigger on a Bob Latino VTA 70

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Hello everyone,

 

Big day for me as after weeks and weeks and weeks of reading and research, and literally years of reading about how nice the sound tube amps provide, I have decided to go ahead and buy and build my first Tube amp, the Bob Latino VAT 70. I had the opportunity several weeks ago to listen to my first tube amp and WOW! I was hooked right then and there.

 

While I have no background with Tubes, I thought it would be a fun project and what better way to learn by building right? I am reasonably intelligent, can read and follow instructions, am handy with my hands, and have the time and will to see this through.

 

I am in no real rush to finish, I just want to enjoy the process, learn, have fun, and maybe (if he shows any interest) work with my Son on this as a co production.

 

So as I move forward with this project, I would love any thoughts, opinions, and ideas to help me prepare. For instance, what is a really nice soldering iron that you guys may have used that you can recommend, or is there a special work surface and or mat I should consider? Are there things I should avoid? Dangers? Caveats? Please, share your opinions and experience (s) with me. Im all ears at this point.

 

My listening area is my man cave/basement.  It is an area bout 12x20, carpeted, with furniture. I have and will initially be using my Fortes until I can save for and find a nice pair of Cornwalls. For a source I will use either my CD63E CD player,  iPod or TT.  I currently have a Technics SL23 currently, but will be saving for and purchasing a nicer rig down the road.

 

I am going to order the VTA 70 over the weekend. So.....help me out guys. 

 

I look forward to any and all  ideas, thoughts, opinions and such!

 

Thanks!

 

Craigster

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I own, and built, the ST-70 earlier this year myself.  Yes, just take your time in building it and mark each step off as you go and don't rush.  I went with most all the upgrades; Russian PIO caps, upgraded power caps, and the Sovtek 6550WE tubes.  I went with the tubes that Bob sold with them as I doubt I can hear major amounts of difference to worry about it.   Not long after, I did go to a Gold Lion 12AU7 center tube which is said to be the one that makes the most difference in SQ overall and left the side pair the same as what they came with.  I also put a Ruby 5A4R rectifier tube and kept the other as a spare. 

 

Is see that now he/they include the speaker terminals where you can wire two taps of the transformers for 4 & 8 ohm speakers.  Those were extra when I got mine but were worth the small amount.    Yes, get the stepped attenuator, too, just in case.  I use a separate preamp but having that extra control in case you have a mis-matched preamp or are going to go from a source straight into the amp is kind of handy. 

 

My avatar is my amp, too.  The thread below shows some of the build on the amp plus the Cornwalls I had for a short time.  I recommend using a variac with it for normal use "IF" your wall voltage is like mine and hovers at 124 to 125v at all times.  Bob recommended around 117v on the amps and likes this variac for the money and is the one I bought.

 

 

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An excellent choice for an amp!  Most importantly, do you have any experience soldering (especially on a pc board)?  If not, it would be worth buying a bag or two of old resistors/capacitors and a bunch of terminal strips (which you can mount on a board) and practice.  There are many video tutorials around on proper technique.  It is easy when first starting out to overheat a component which can cause it to fail, and it is possible to damage pc board pads with excessive heat.  

 

Any non-conductive surface is fine for doing electronics work and, if you are working on a concrete floor, a rubber mat under your feet provides an extra level of safety.  I also recommend installing a GFI outlet into which you can plug the amp when testing and measuring.  It's a very inexpensive way to make things much safer.  

 

Maynard

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1 hour ago, tube fanatic said:

An excellent choice for an amp!  Most importantly, do you have any experience soldering (especially on a pc board)?  If not, it would be worth buying a bag or two of old resistors/capacitors and a bunch of terminal strips (which you can mount on a board) and practice.  There are many video tutorials around on proper technique.  It is easy when first starting out to overheat a component which can cause it to fail, and it is possible to damage pc board pads with excessive heat.  

 

Any non-conductive surface is fine for doing electronics work and, if you are working on a concrete floor, a rubber mat under your feet provides an extra level of safety.  I also recommend installing a GFI outlet into which you can plug the amp when testing and measuring.  It's a very inexpensive way to make things much safer.  

 

Maynard

Maynard, 

 

Thank you for the post. I have some experience with soldering but definately see the value in your suggestion about practicing prior to soldering on the amp itself.

 

I will get a rubber floor mat and use the GFI outlet close to my work bench. 

 

Craigster

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2 hours ago, avguytx said:

I own, and built, the ST-70 earlier this year myself.  Yes, just take your time in building it and mark each step off as you go and don't rush.  I went with most all the upgrades; Russian PIO caps, upgraded power caps, and the Sovtek 6550WE tubes.  I went with the tubes that Bob sold with them as I doubt I can hear major amounts of difference to worry about it.   Not long after, I did go to a Gold Lion 12AU7 center tube which is said to be the one that makes the most difference in SQ overall and left the side pair the same as what they came with.  I also put a Ruby 5A4R rectifier tube and kept the other as a spare. 

 

Is see that now he/they include the speaker terminals where you can wire two taps of the transformers for 4 & 8 ohm speakers.  Those were extra when I got mine but were worth the small amount.    Yes, get the stepped attenuator, too, just in case.  I use a separate preamp but having that extra control in case you have a mis-matched preamp or are going to go from a source straight into the amp is kind of handy. 

 

My avatar is my amp, too.  The thread below shows some of the build on the amp plus the Cornwalls I had for a short time.  I recommend using a variac with it for normal use "IF" your wall voltage is like mine and hovers at 124 to 125v at all times.  Bob recommended around 117v on the amps and likes this variac for the money and is the one I bought.

 

 

Excellent post and future resource for my build!

 

Do you still have the VTA 70 connected to the Cornwalls?

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2 hours ago, ccdowenye said:

Excellent post and future resource for my build!

 

Do you still have the VTA 70 connected to the Cornwalls?

 

No.  I sold the Cornwalls. It runs my CF-3's great,  though, and I know it will run the Belle clone speakers I'm building too. You'll enjoy the amp build. It was a lot of fun. 

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22 hours ago, wdecho said:

https://www.parts-express.com/stahl-tools-stssvt-variable-temperature-soldering-iron-station--374-100

 

Love mine.

 

When dealing with live amp, one hand in pocket rule and you should be fine. Congratulations. 

I started with this and it is certainly good for the money!

 

I'm glad I stepped up to the Weller https://www.amazon.com/gp/product/B000BRC2XU/ as it seemed to be more consistent, hotter, and more comfortable to use.  

Some various extra tips: https://www.amazon.com/gp/product/B00KV8E2HS/

I see the Weller isn't on sale anymore and the tips are out of stock.  Might find a better price elsewhere.

 

Cool project!  Have fun and be safe!

 

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