[Amps] THE SKINNY ON MY AL-82

[Carl]

----- Original Message ----- 
From: "Jim Thomson" <jim.thom at telus.net>
To: <amps at contesting.com>
Sent: Thursday, December 18, 2014 12:22 PM
Subject: [Amps] THE SKINNY ON MY AL-82


> Date: Thu, 18 Dec 2014 07:14:01 -0800
> From: "Jim W7RY" <w7ry at centurytel.net>
> To: "Bill and Liz" <magoo at isp.ca>
> Cc: AMPS <amps at contesting.com>
> Subject: Re: [Amps] THE SKINNY ON MY AL-82
>
> Is he (YOU) SURE it was parasitics?   More likely hot switching of the
> amplifier T/R relay. This causes LOTS of problems that folks THINK are
> parasites.
>
> After I install my QSK system into amplifiers, the arcing completely STOPS
> because the relays are no longer hot switched.
>
> ALC overshoot spikes also cause arcing in amplifier capacitors.  Mostly
> Kenwood has ALC overshot including the TS-590S.
>
> Although, the Icom IC7410 has ALC overshoot problems on SSB. Which is
> repaired by Icom for free. Although only the units made before mid 2014 
> are
> affected.
>
> 73
> Jim W7RY
>
> ##  The AL-82 is known as the...firecracker !   It’s a parasitic prone 
> amp, right out of the box.
> The Rich measures suppressor will solve the parasitic issues 100%.... 
> except his suppressors
> run hot on 10m.   Hotswitching wasn’t the issue... but will make it 
> worse..ditto with overshoot.
> A conventional suppressor will work, but the trick is finding  non 
> inductive resistors these days.
> To tame the parasitics with a conventional suppressor, it requires 
> slightly more L.... which will
> cause the resistor to run warm / hot  on 10m.    A 10/15 watt globar is 
> the real solution...works good.
> Then used wide silver plated strap for the suppressor coil.
>
> ##  KM1H used a method, with caps in series with new style mof 
> resistors... to cancel out the xl of the
> mof resistors.   2-5 x 3 watt  mof resistors in parallel will provide 
> enough heat handling capability on 10m,
> but will require  2-5 x series caps.  If you can find some old style 
> Carbon comp resistors, 2-5 of em in parallel
> will work.   A single 10-15 watt globar is the no brainer solution.   Or 
> leave the rich M suppressor in there,
> and don’t operate it on 10m.
>
> ##  KM1H has had a lot of experience with that amp.  Hopefully he will 
> chime in.
>
> Jim  VE7RF

That is the same suppressor Ameritron copied but used a 100 Ohm 3W resistor 
and 91pf vs 100pf caps.

I use a 5W 50 Ohm MOX or a pair of 100 Ohm in parallel; only 2 caps needed. 
Use the standard 3 1/2T of #16 wound over a 2W carbon resistor or similar. 
Place next to the 5W resistor and not wound around it.

You get better suppression with the lower resistance since it further lowers 
the Q and broadens the frequency response.

To replace 2W carbons use the 50 Ohm Ohmite OY ceramic resistor, reuse the 
original coil external to the resistor.


>
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