Actual information on Claravox

Posted: 8/21/2021 10:49:54 PM
bendra

From: Portland, Oregon

Joined: 2/22/2018

"To my eye this looks like a handwound coil. Am I very wrong?"  - bendraI'm pretty sure it's a commercial RF choke, like those in the EW.  They're sorta scramble-wound, but there's a method to their madness.Hey, can I persuade you to crack yours open and take some more detailed pix of the guts?  I'm most interested in the oscillator boards.

What, you are going to ask the one guy with a working instrument? Sorry, I'm much too big a chicken!

Posted: 8/22/2021 3:02:41 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"What, you are going to ask the one guy with a working instrument?"  - bendra

Haha!  You're right, I should go pester DiggyDog, since he'll probably end up putting the rib spreaders on his.

Posted: 8/22/2021 7:46:10 PM
hudri

Joined: 2/6/2021

Here is the volume oscillator. Still hesitant to dismantle the pitch side because this seems to be working...

Posted: 8/22/2021 8:31:55 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

hudri that's awsome, thanks! 

Can you read the IC number of U7, it maybe looks like a TI part? 

What I thought were trim pots are surface mount electrolytics, silly me. 

VR1 is a trimmer though, I wonder what it does...

Twin RF chokes are a bit of a surprise (I though the boards would be symmetrical) though it makes sense as the SRF of a single choke is too low, and it looks like they're using the tap point via D6.  The vertical one in this photo (L16) appears to be somewhat bent over, which could have happened in shipment - you might want to gently reposition it back to vertical to get it away from the metal can of L19.  If I were Moog Inc. I'd put a bunch of silicone splooge on there to better physically anchor them.  Better yet, make a plastic protector / carrier of some sort.

Do you have any shots of the backside to share?

Posted: 8/23/2021 12:52:39 PM
hudri

Joined: 2/6/2021

So here are some more photos:


backside of volume osc.




pitch osc front and back.

On both boards, the IC is a TL072C opamp, and the adjustable inductor has marking 748N.

So who stole the chokes from my pitch oscillator, and why is this side working while the volume osc has problems?

Posted: 8/23/2021 3:48:59 PM
Flounderguts

Joined: 10/24/2020

TL072CD, looks like. Those are in short supply, just now. We have some on order, and they are 19 weeks out as of today. 

Posted: 8/23/2021 4:25:40 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"So here are some more photos:"  - hudri

Wow, many, many thanks for those!

"On both boards, the IC is a TL072C opamp, and the adjustable inductor has marking 748N."

Thank you sir (or ma'am?)  for that too!

"So who stole the chokes from my pitch oscillator, and why is this side working while the volume osc has problems? "

EDIT: IGNORE MY FOLLOWING BLATHER, THE CHOKES ARE IN THE PITCH ARM!

This is really unexpected, and runs counter to the info directly supplied by Moog's technical representative to those of us at TW here: [LINK]

Does the pitch side use a series EQ inductor to improve linearity?
I am not sure exactly what you are referring to but I will assume you mean the coil between the antenna and the oscillator.  Yes, absolutely!  We have a custom 3-Pi inductor wound for Claravox to match the antenna impedance with the L-C tank impedance.

It almost certainly runs counter to the pitch side voltage swing spec of ~35Vpp given in that same post, and could very well explain the pitch jumpiness documented by member tcordara on Claravox serial #34.  I'm not seeing any ESD protection either (another Moog claim).

The Claravox pitch oscillator is quite disappointing.  Why on earth would they remove those chokes, right at the beating heart of the Claravox?

Posted: 8/23/2021 7:03:01 PM
bendra

From: Portland, Oregon

Joined: 2/22/2018

Dewster, from the same Q&A linked, does this mean the coil is contained in the pitch arm? Or is that just stupid?

Does the pitch arm contain active electronics within or is it similar to the EW Pro with only passives?
The pitch arm only contains passive components – a custom-design 3-Pi coil is used for impedance matching.

Posted: 8/23/2021 8:05:51 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"Dewster, from the same Q&A linked, does this mean the coil is contained in the pitch arm? Or is that just stupid?"  - bendra

Ah, excellent catch!  Yes the board seems laid out for either option, and that's probably what's going on.  Thanks, and very sorry for the confusion.  I edited my baseless blather.  I'm an idiot.

Posted: 8/25/2021 10:04:08 PM
gingercat

From: Whanganui, New Zealand

Joined: 11/4/2020

Hmm... there seem to be more people each time I check having problems with the Claravox. Are these a minority? (all technology has a failure rate, I understand this) Are there people out there that have received the Claravox and are having no issues and are happy with their purchase? Love to hear from you. Wife still wants to go ahead with purchase, I am getting a little nervous as we live in Australia and not so easy to send back I'm guessing for a service.Cheers.

Its worse for me I'm in NZ  

My hope is that as the model numbers get higher and delivery times later some of these issues will have been ironed out. I would prefer a model number over 1,000 then I know there are at least that many tested before I get mine

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