ARC VT-60 Cloned :-)

[ANADIGIT]

I will receive PCB from my group buy of ARC VT-60 SE but I can't find where's a source of LM329 IC's ?

Schematic included 3*6DJ8, 4*6550 and I decide to use Hammond 1650P, too

 

[ANADIGIT]

Our PCBs

Plate through hole double layer with SILVER PLATED and 2 times of FR4 and CRYO TREATED

 

[DigitalJunkie]

I will receive PCB from my group buy of ARC VT-60 SE but I can't find where's a source of LM329 IC's ?

Schematic included 3*6DJ8, 4*6550 and I decide to use Hammond 1650P, too

Digikey has some:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LM329DZ-ND

You might also get by with a couple of 6.9V Zeners.

 

[ANADIGIT]

comparing ?

Does 6.9V zener diode better than LM329 ?
How are noise and regulation ?

Does anyone know about brand name of filter capacitor (470uF and 100uF) ?

Thanks

 

[analog_sa]

Hi Anadigit

Thanks for publishing the circuit. Taking into account the high signal level circuits the regulator is powering, there should be no real degradation using a zener. The 470uF and the low voltage electrolytics are Nichicon, the 100uF probably Chemicon.

 

[kraljmatjaz]

May i ask you where did you get the VT-60 pcb's. Where is the group buy?

Regards,
Boris

 

[SY]

Is that circuit correct? There's one or two things that don't look right.

Cryotreating a circuit board (besides being useless) can reduce reliability. NOT a good idea.

 

[ANADIGIT]

Cryo ?

Hi, SY
Why don't you think CRYO not good for audio ?
I seen there're many website used this method to improve their goods.

This circuit came out from service manual but I think there're many revision of them.

Thanks

 

[SY]

It is not a good process for circuit boards (will hasten delamination). I have serious reservations about reliability considerations for other components (especially tubes).

Was the circuit redrawn from the manual? If so, that could explain the errors.

 

[ANADIGIT]

Example

Cryo used for make everything reliable such as COPPER when you treated your interconnect it will be smooth and easy to solder because its molecule will recontruction.

BTW this method can made your money lost but it can make me happy.

What's wrong in schematic ?

 

[SY]

I don't follow the analogy to wire (especially because it's not correct).

 

[jerluwoo]

The first thing that stands out as being incorrect in the schematic is the ccs in the tail of the phase splitter section.

 

[analog_sa]

It is very unlikely the ccs is a bipolar anyway.

 

[SY]

That IS a CCS, but unfortunately, the current is zero.

 

[kevinkr]

I'm assuming that transistor shown in the ccs circuit was meant to be a jfet.. (In any case it is not a great ccs.)

One thought about the LM329 is that it will require far less current than the typical zener for normal operation, it also has a much smaller temperature coefficient than most zeners - that said a 6.9V zener typically has a relatively low temperature coefficient.

The only other thing I will add is that ARC solid state high voltage regulators are not very reliable IME, although in this application the plate load resistors provide enough isolation from potential load faults that this might not be an issue, line transients are another issue...

 

[Guiness]

Maybe this might help you Anadigit...

http://www.diysong.com/images/VT60SE.htm

or

 

[Guiness]

and

 

[analog_sa]

"Model Freedom"? Interestingly, this amp is so cheap used that it probably costs more to build a clone.

 

[jerluwoo]

The schematic given here is the same as in the first post.
http://www.diysong.com/images/vt60report01/vt60se.jpg

 

[ANADIGIT]

Our chassis

Next week our chassis group buy will be complete, my friend he used CNC for build this chassis !

My friend tested CCS already, it's OK and good for current control when you change value of resistor.

Now I waiting for my KT88 JJ and 6N1p for test our PCBs.

Thanks
Anadigit