[sdiy] [AH] U726hc Real deal?

[Tom Bugs]

I guess there's a few other ways, yes, to do a matched pair with 
integral heater.. but the idea here was really a drop-in clone for the ua726
(not that I actually have any personal need for them - just aware of the 
ridiculous scarcity pricing that keeps cropping up - and figured it 
looked do-able - ie. fun project potential, not that I really need more 
projects..)
Also MAT04 now says obsolete.. THAT300 series would be a fine 
replacement in that case.
Ta, Tom

On 09/09/2015 18:36, Rick Jansen wrote:
> Use a mat04.. Two transistors as the matched pair, one as heater, one 
> as sensor. One external transistor as a clamp. See the circuit at the 
> bottom of http://dropmix.xs4all.nl/rick/Emusic/Moog/moogvcf_schematic.gif
>
> Rick
>
> On 09 Sep 2015, at 15:19, Tom Bugs <admin at bugbrand.co.uk 
> <mailto:admin at bugbrand.co.uk>> wrote:
>
>> I wondered before why no-one seems to have done a clone of the ua726.
>>
>> Doesn't *SEEM* all that complex?!
>> A nice matched pair (eg LS318) is the main core.
>> 6 transistors (I presume general purpose?), 2 x 6V2 zeners and 6 
>> standard resistors.. - those parts being for the heating element.
>>
>> Get the pin placement right, encapsulate it in goo..
>>
>> What am I wrong on?
>>
>> [I don't want to fully take on such a project, though could 
>> potentially do a design up for initial testing with a view to someone 
>> running a production in a friendly open-source-ish manner]
>>
>> Tom
>>
>>
>>
>> On 09/09/2015 14:00, . . wrote:
>>> Wow don't pay 90$ for that!
>>>
>>> I've bought a few fakes some years ago for about 10-15$ each iirc 
>>>  They worked according to my tech at the time.   It's hard to say if 
>>> they perform exactly the same, I ended up putting in a real one in 
>>> just to be sure.
>>>
>>>
>>>
>>> On Wed, Sep 9, 2015 at 7:42 AM, Synth Parts 
>>> <synthpartsdotcom at gmail.com <mailto:synthpartsdotcom at gmail.com>> wrote:
>>>
>>>     Also very suspicious is the pic of the one with the year 2000
>>>     date code and that there's no pics showing the pins (they were
>>>     gold on the real ones)...
>>>
>>>     Doug
>>>     synthparts.com <http://synthparts.com>
>>>
>>>     On Wed, Sep 9, 2015 at 4:34 AM, Kenny Balys <kenny at beatkamp.com>
>>>     wrote:
>>>
>>>
>>>         I doubt that these were ever shipped to, or made in China so
>>>         I would look elsewhere. Its hard to imagine that in the
>>>         1970's, Fairchild, in the height of the cold war, would be
>>>         manufacturing vital components such as these in China.
>>>
>>>         On 09-09-15 09:29 , Synth Parts wrote:
>>>
>>>             I recognize that sellers name as one selling fake
>>>             SSM2040s a while back.
>>>             Lots of feedback regarding fake parts -
>>>
>>>             http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=polida2008&iid=400613597638&de=off&items=25&which=negative&interval=365&_trkparms=negative_365
>>>
>>>             Doug
>>>             synthparts.com <http://synthparts.com>
>>>
>>>             On Tue, Sep 8, 2015 at 10:30 PM, Larry Dee
>>>             <mintlake at bctonline.com> wrote:
>>>
>>>                 Is this the real thing?
>>>
>>>
>>>                 http://www.ebay.com/itm/1PCS-CONTROLLED-DIFFERENTIAL-PREAMPLIFIER-IC-FAIRCHILD-TO-100-CAN-10-UA726HC-/400613597638?hash=item5d466e61c6
>>>
>>>
>>>
>>>                 I’m so burned out on this issue – sheeeesh for $90
>>>                 it better be NOS.
>>>                 Tried searching the AH archives for recent content
>>>                 on this subject but did
>>>                 not get anywhere.  Sorry to be redundant, but what
>>>                 is the latest word on
>>>                 this part?
>>>
>>>
>>>
>>>
>>
>> -- 
>> BugBrand LTD
>> UK company No. 07199808
>> VAT No. GB 988 2629 57
>> 1 Ninetree Hill
>> BRISTOL BS1 3SB
>> United Kingdom
>> www.bugbrand.co.uk
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl <mailto:Synth-diy at dropmix.xs4all.nl>
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
BugBrand LTD
UK company No. 07199808
VAT No. GB 988 2629 57
1 Ninetree Hill
BRISTOL BS1 3SB
United Kingdom
www.bugbrand.co.uk

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20150909/97a89070/attachment.htm>