[Hammarlund] HQ-180(A) Audio Fidelity Mod - Question

[Dallas Lankford]

Hi Rodney,

Your proposed mod may be better.  Why don't you do the two mods, make some
measurements for each mod, and report back to the reflector?

My approach is modeled after the R-390A negative feedback approach, it is
simple, it works well, and it sounds great.  But others may want to try
something else.

Best regards,

Dallas


----- Original Message -----
From: "Rodney Bunt" <rodney_bunt at yahoo.com>
To: "Dallas Lankford" <dallas at bayou.com>; <hammarlund at mailman.qth.net>
Sent: Tuesday, April 12, 2005 11:34 PM
Subject: Re: [Hammarlund] HQ-180(A) Audio Fidelity Mod - Question


> Dallas,
>
> I have been looking at your Audio Fidelity fix.
>
> The 620K resistor from Plate of Output tube to cathode of first Audio
tube, would upset the tube
> first audio bias. Would it not make more sense to insert a capacitor in
this "feedback" circuit,
> thus blocking the DC component ?
>
> Using a .01uF would give a 6bB rolloff at 25Hz, now that is tons of
bass....
>
> Your thoughts ?
>
> Rodney
> VK2KTZ
>
>
>
>
> --- Dallas Lankford <dallas at bayou.com> wrote:
> > I never liked the so-called auto-response audio filter in the 180 series
> > receivers.  It makes the audio sound tinny because of the bass cut and
> > boosts the treble which enhances distortion products, just what we don't
> > want.  My downloadable mod which fixes these problems is in The Dallas
Files
> > at the web site below.
> >
> > http://www.kongsfjord.no/
> >
> > _______________________________________________
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