ARC VT-60 Cloned :-)

[6A3sUMMER]

geladk
and
Yamaoka

None of your beautiful photos have 6550 tubes.

Yamaoka, you are using EL34 tubes.
geladk, What output tube types are you using?
Thanks!

The schematic, Post # 39 shows 6550 tubes.

 

[geladk]

Some pictures of my spare PCB.

 

[Yamaoka]

geladk
and
Yamaoka

None of your beautiful photos have 6550 tubes.

Yamaoka, you are using EL34 tubes.
geladk, What output tube types are you using?
Thanks!

The schematic, Post # 39 shows 6550 tubes.

Yes, I use EL34 Mullard Blackburn Xf2 and XF3 , Brazilian Miniwatts, JJ and 6CA7 Shuguang Blck Treaure!

 

[geladk]

geladk
and
Yamaoka

None of your beautiful photos have 6550 tubes.

Yamaoka, you are using EL34 tubes.
geladk, What output tube types are you using?
Thanks!

The schematic, Post # 39 shows 6550 tubes.

Mine are Svetlana 6550C Winged C.

 

[6A3sUMMER]

geladk,

I never saw 6550s that had straight glass envelopes.
Well, now I have.

 

[Yamaoka]

I'm thinking if I should follow the PCB and find out source follower/ccs that was supposed to be used here or go back to the orginal RLC version. Any experience or suggestions?

 

[Yamaoka]

While I study and try to find information aboit the best parts to use in that specific part of the circuit, my VT60 is coming back to life with

 

[DrDyna]

Some pictures of my spare PCB.

Do you still have this board by chance?

 

[DrDyna]

I'm thinking if I should follow the PCB and find out source follower/ccs that was supposed to be used here or go back to the orginal RLC version. Any experience or suggestions?

I'm sure you've figured it out by now, but mine had a DN2535 bodged in on the top of the board, not unlike how ARC does in the vt-100. I had some small boards made for it that will fit in the bodge location instead. They haven't gotten here yet, so no testing has been done. If my re-bodge attempts work out nicely, the next thing on my radar is adding some trimmer bypassed resistors on the cathodes of the output tubes so they can be adjusted individually.

I'm not sure what your board is supposed to have, I've seen a few different configurations.

Mainly I'm trying to stoke the fire of this thread as I progress through modding my original, and I'm looking for as many opinions and options as I can gather. I want this thing to be bulletproof once it's running. 🙂

 

[geladk]

Do you still have this board by chance?

I still have it. However, it is not for sale.

 

[soulmerchant]

Hi @geladk which transformers did you source? I see they are made in Germany.

Best regards
Ian

 

[geladk]

@soulmerchant, I had the transformers custom made by a German company, Ritter Electronics by Jörg Ritter. Back in 2012. Very nice work at a reasonable price. Unfortunately, the company no longer exists.

 

[DrDyna]

Could I impose on one of you and kindly tell me which part are you using for this? I've seen a few that don't even have this.

 

[geladk]

Could I impose on one of you and kindly tell me which part are you using for this? I've seen a few that don't even have this

I have used a Delevan 1945-01K. They were in stock at Mouser when I built mine. Something similar is suitable.

 

[jimmy50]

It is Resistor 54.9 Ohm parallel with Coil (RF Inductor) P/N 78F2R7J-RC.

 

[schiirrn]

You can also wind a piece of magnet wire over a resistor. Value is not super critical, 12 turns will do.

 

[geladk]

On my version of the board, R38 and L are two separate components.

 

[DrDyna]

Thank you all, very much appreciate it 🙂

 

[DrDyna]

If I can ask one more question, it was mentioned by 6a3summer but I didn't see much talk about it, how are 6550s (and maybe kt120s if anyone's tried it) holding up with the high grid leak resistors?

Has anyone swapped them for lower max Rg values, and if so, can the 6922s still drive the outputs reasonably?

 

[DrDyna]

This guy was an smd part I salvaged. Broke the plastic housing off of it and unwound a few turns.

We gonna be good with this?