Dolly amp, v2.0

[Redboy]

Nice work. I like the recessed tube attachment plate, clean look for the top :thmbsp:.

That was the goal, and I'm pretty happy with how it turned out. I looked for ways to completely eliminate screw heads from the top, but it would have been a lot trickier to get there.

 

[dnewma04]

Very cool, Nate. Good work.

 

[dokblues]

Very nice work Nate!! Looks great and as usual with all your work Da*# I`m impressed!!:thmbsp:

 

[Redboy]

Thanks for the kind words, fellas!

 

[Urizen]

I've been running the MC30s in the system lately, and when I dropped this amp in I was amazed at how little was lacking in comparison.

:thmbsp:

Great looking work, Nate. I wish I could hear that one.

 

[jaymanaa]

Damn nice work Nate! :thmbsp:

 

[willyrover]

Nice looking and and schematic! I'm interested in building one of these with a set of iron and tubes I have. Mine would use SS rectification instead of the EZ81.

Any chance of getting the voltages at B+ and *?

 

[ejfud]

Hey Nate, what was the final build cost?

 

[Redboy]

Nice looking and and schematic! I'm interested in building one of these with a set of iron and tubes I have. Mine would use SS rectification instead of the EZ81.

Any chance of getting the voltages at B+ and *?

willy, I measured some voltages in another thread. Here.

It's not on the schematic, but the first resistor in the power supply is 390 ohms, the second is 330 ohms.

I'd like to compare this one to a SS rectified version someday.

 

[Redboy]

Hey Nate, what was the final build cost?

Gary, a couple people have asked that question. I'll have to put together an official tally so I can answer it intelligently.

The biggest cost is in the iron, which was around $90 shipped. This Hammond box runs about $27, and I don't know what the tubes would cost - mine are all console pulls. The other little bits and pieces might total $30 - $50, depending on what resistors you used. I like these Kiwames a lot - I used them in your Maggie - but there are less expensive options available.

 

[DENNYDOG]

Things were a bit different back then huh Nate? The kitty seems to like the music. :yes:

What ever happened to that Pilot?

[/IMG]

 

[Redboy]

Yeah, a little different. But good, nonetheless.

Snade has that Pilot now, as far as I know.

 

[Redboy]

Hey Nate, what was the final build cost?

Okay, I worked up a parts list with costs. Total as built would run very close to $200 without tubes, if you used these parts and paid full price for everything.

Anyone interested, please PM me and I'll send you an excel file. :thmbsp:

 

[willyrover]

willy, I measured some voltages in another thread. Here.

It's not on the schematic, but the first resistor in the power supply is 390 ohms, the second is 330 ohms.

Excellent! Thanks!

Also noticed that your amp omits the 100k pot at the input. Did you replace this with any resistor or run the input directly into the 12AX7?

 

[wajobu]

Continuing to look great Nate!

 

[Redboy]

Excellent! Thanks!

Also noticed that your amp omits the 100k pot at the input. Did you replace this with any resistor or run the input directly into the 12AX7?

I ran it straight in, but I use a passive pre which is basically just a 100K pot in a box - the Harry Haller passive.

 

[willyrover]

What are the values of resistors on pin3/8 of 12AX7 and pin 2 of EL84?:scratch2:

 

[Redboy]

What are the values of resistors on pin3/8 of 12AX7 and pin 2 of EL84?:scratch2:

Huh, I guess I hadn't completely finished my schematic when I took a picture of it...

Off pins 3/8 of 12AX7 to ground is 2.2K

Connected to pin 2 of EL84 is 1K

You going to put one of these together, willy?

 

[willyrover]

Great! Thanks!

Yes, I have a set of old iron from a SE 6BQ5 console amp. Nothing fancy. Ordered new sockets. Just getting together a parts list and need to find a suitable chassis. I'd like to match the cosmetics to the other amp and preamp I built. Probably go half the width.

 

[Redboy]

Great! Thanks!

Yes, I have a set of old iron from a SE 6BQ5 console amp. Nothing fancy. Ordered new sockets. Just getting together a parts list and need to find a suitable chassis. I'd like to match the cosmetics to the other amp and preamp I built. Probably go half the width.

All right! Let me know if you need anything else - I can email my parts list to you if you think that would help.

FWIW, the Edcor OPTs are pretty outstanding in this thing if you find that yours are lacking. At $20 apiece, they're hard to beat and build quality is top notch! Build it with yours first though - as you know, much of that old iron had magic cooked into it!