[mb3k]

I've been trying to gather some solid info on making a JISBOS ready SOHA, but it's like searching through a jungle!

In April, Regal put together a list of parts to change (see post here). Being 8 months old now I'm not sure if all the changes are necessary or valid.

Does anyone have any recommendations on this?
I've been out of the loop for a couple months now, so my groove is off.

Happy holidays!

 

[MisterX]

If you a question about the JISBOS buffers please post it in the headwize thread.
That way people do not have to try to search "through a jungle" to find the correct answers.

 

[keyid]

Will be eagerly waiting on any updates to mb3k.com
I just finished my soha couple days ago and your walkthrough was invaluable.
Any updates for the jibos and soha would be awesome!

 

[Eokboy]

A lingering question not answered in the Headwize thread: Can I omit the 1N4148 protection diodes?

 

[mb3k]

Quote:

Originally Posted by MisterX /img/forum/go_quote.gif If you a question about the JISBOS buffers please post it in the headwize thread. That way people do not have to try to search "through a jungle" to find the correct answers.

I tried to post that in the thread a while ago. AMB touched on it by indicating that heatsinks on the SOHA voltage regulators may be a good idea, but nobody else has commented on the rest.

 

[Ferrari]

I was not aware of the Regal part changes list, but this is the changes (comparing to stock parts list) I have made on my SOHA to use with JISBOS 3-channel active ground, quiescent current is set at 60mA

:

VR1 and VR2 are 15V type (7815/7915) on large heatsink (actually the side panels of a HiFi-2000 enclosure)
C9 and C10 are 3300uF/50V bypassed with small value film cap on bottom side
C7 and C8 are 100uF/50V bypassed with small value film cap on bottom side
C4, C5 and C6 are 220uF/100V
C2 and C14 are 220nF PIO (many types capacitors can be used here)
Jumpers on R6, R16 and jumpers across pins 1 and 3 (R channel) and across pins 5 and 7 (L channel) of OPAMP... and use the alternative wiring methode as described by AMB. More information can be found at Steinchen JISBOS website or AMB post in the JISBOS thread at Headwize.

Except the jumpers on the output part and the PIO caps, the components changes mentioned above are implemented in my first SOHA with monolithic output buffer (OPA627/BUF634) a while back.

 

[regal]

The post I made a while back was compiled from Runelight ans Steinchen recommendations at the time. It seems people are getting by with less.


For AMB's alternative wiring scheme does anyone have a pinout # diagram for the opamp socket?

 

[MisterX]

Quote:

Originally Posted by mb3k /img/forum/go_quote.gif I tried to post that in the thread a while ago. AMB touched on it by indicating that heatsinks on the SOHA voltage regulators may be a good idea, but nobody else has commented on the rest.

There is you answer then.

I think it is fair to assume that if someone had a problem with something on Regal's list they would have pointed it out a long time ago.

Quote:

does anyone have a pinout # diagram for the opamp socket?

It's a standard dual channel op-amp configured as a unity gain buffer so.....

 

[MisterX]

Quote:

Can I omit the 1N4148 protection diodes?

Only if you change the JISBOS R1 and R2 values as outlined in the "alternative wiring scheme" (this forms a voltage divider with approximately 4x attenuation so there is no chance of the output from the tube swinging beyond the JISBOS power rails)

 

[eruditass]

el_matt0 has told me that the critical upgrade is the VR1 and VR2 to TO-220 style 15V regs

 

[Ferrari]

Quote:

Originally Posted by regal /img/forum/go_quote.gif ... For AMB's alternative wiring scheme does anyone have a pinout # diagram for the opamp socket?

That can be found at Steinchen JISBOS website, see assembly part

.