[NJARC] Knight KX-60 Amplifier

[Chuck]

Hi Rich,
I think I got the right type from Al tonight at the meeting.
I'm going to give that a try tomorrow.
I'll let everyone know if it works...

Thanks for the heads-up Rich!

Chuck


-----Original Message----- 
From: Rich
Sent: Friday, June 10, 2016 9:04 PM
To: Mike Feher ; 'Chuck' ; njarc at mailman.qth.net ; Al Klase
Subject: Re: [NJARC] Knight KX-60 Amplifier

Hi guys,

I use to repair those old transistor car radios and just wanted to say that
as you know most used Ge PNP power transistors. Substituting a silicon PNP
will usually result in cross-over distortion due to the difference in the
base-emitter bias voltage.  Give it a try, it will not cause any damage,
just a good possibility of distortion.

Good Luck with it,
Rich L.

--------------------------------------------------
From: "Al Klase" <ark at ar88.net>
Sent: Friday, June 10, 2016 1:34 PM
To: "Mike Feher" <n4fs at eozinc.com>; "'Chuck'" <cpaci1 at verizon.net>;
<njarc at mailman.qth.net>
Subject: Re: [NJARC] Knight KX-60 Amplifier

> Just remember
> Reply = Poster
> Reply All = Everyone
>
> _________________________________________________________
> Chuck,
>
> Mike's analysis has been spot on.  In this particular circuit, silicon 
> should work just fine, that's not always the case.
>
> In the mean time I dug through my Germanium power box, and will bring some 
> PNP TO-3 along to the meeting.
>
> Mike, can you take a SWAG at the required HFE (gain).  I'm thing 10 would 
> be sufficient.
>
> Al
>
> Al Klase – N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
>
> On 6/10/2016 12:35 PM, Mike Feher wrote:
>> Chuck -
>>
>> Even without going downstairs, which I try to avoid nowadays, I found 
>> some
>> 2N4398s by Motorola that are NOS. These are TO-3 PNPs but silicon. I am 
>> sure
>> they will work just fine in that circuit. You can pick them up, or, I can
>> mail them to you. Here is the data sheet. 73 - Mike
>>
>> http://www.nteinc.com/specs/original/2N4398_99.pdf
>>
>> Mike B. Feher, N4FS
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960
>>
>>
>> -----Original Message-----
>> From: Chuck [mailto:cpaci1 at verizon.net]
>> Sent: Friday, June 10, 2016 11:09 AM
>> To: Mike Feher; 'Al Klase'; njarc at mailman.qth.net
>> Subject: Re: [NJARC] Knight KX-60 Amplifier
>>
>> Thank you Mike.
>> You have been a great help!
>> And -- I would be more than happy to pay for those transistors.
>> See you tonight at the meeting.
>> Thanks again!!!!!!!
>> Chuck
>>
>> -----Original Message-----
>> From: Mike Feher
>> Sent: Friday, June 10, 2016 10:57 AM
>> To: 'Chuck' ; 'Al Klase' ; njarc at mailman.qth.net
>> Subject: RE: [NJARC] Knight KX-60 Amplifier
>>
>> If I find a couple you can have them. I just have to go downstairs and
>> check, but, I know I have them. They are really not that critical as the
>> voltages on all three junctions is essentially the same. Your only real
>> criteria is that they be PNP in a TO-3 style package. Even NPNs would 
>> work,
>> but would require some circuit topology of the PS to change. Even silicon
>> will work, giving you a few tenths of a volt less out. Will let you know 
>> as
>> I have thousands. 73 - Mike
>>
>> Mike B. Feher, N4FS
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960
>>
>>
>> -----Original Message-----
>> From: Chuck [mailto:cpaci1 at verizon.net]
>> Sent: Friday, June 10, 2016 10:09 AM
>> To: Mike Feher; 'Al Klase'; njarc at mailman.qth.net
>> Subject: Re: [NJARC] Knight KX-60 Amplifier
>>
>> Hi Mike,
>> That sounds very plausible.
>> My experience with solid state is fairly limited and this power supply
>> circuit design is new to me.
>> If you do find a couple transistors that will work, I will buy them from
>> you.
>>
>> Thanks Mike...
>> Chuck
>>
>> -----Original Message-----
>> From: Mike Feher
>> Sent: Friday, June 10, 2016 7:16 AM
>> To: 'Chuck' ; 'Al Klase' ; njarc at mailman.qth.net
>> Subject: RE: [NJARC] Knight KX-60 Amplifier
>>
>> Chuck -
>>
>> I believe on this case the transistors are acting as C multipliers using 
>> the
>> Miller effect. The diodes are doing the rectification. I have lots of PNP
>> power Ge transistors. 73 - Mike
>>
>> Mike B. Feher, N4FS
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960
>>
>> -----Original Message-----
>> From: NJARC [mailto:njarc-bounces at mailman.qth.net] On Behalf Of Chuck
>> Sent: Friday, June 10, 2016 4:40 AM
>> To: Al Klase; njarc at mailman.qth.net
>> Subject: Re: [NJARC] Knight KX-60 Amplifier
>>
>> Just remember
>> Reply = Poster
>> Reply All = Everyone
>>
>> _________________________________________________________
>>
>
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