Reviewer's Addendum
Possibly, our sample PAT-4 did have "a noisy front- end transistor" (see "Manufacturer's Comment") but since both channels were equally noisy when using the high-level phono inputs, and since noise was extremely low when using the low-level inputs, we did not get the impression that we were testing a defective sample. Dynaco offered us the schematic for an input equalizer like the one we tried to put together, except that this one works. We accept the offer with many thanks. Further Thoughts, from June 1970 (Vol.2 No.10)
In our report on the Dyna PAT-4 preamplifier, we stated that we were unable to tell whether the unit was in or out of circuit when we fed a signal to one of its high-level inputs and then bypassed it entirely. This is no longer the case.
We are not sure whether our hearing acuity has improved or whether our PAT-4 has changed in some subtle way, but we now find a very slight loss of transparency when the PAT-4 is inserted in the signal path. It is still, however, better in this respect than anything we have tested to date, so the gist of that test report remains essentially unchanged.—J. Gordon Holt
A letter about the PAT-4 was published in March 1971 (Vol.2 No.12)
Editor: After having put up, grudgingly, with the very poor volume-control tracking on my Dyna PAS-3 preamp, I was disappointed and frustrated to see that you made no comment at all about this aspect of the PAT-4's performance.
Can you tell me how they compare, or was the PAT-4's tracking too bad
to mention?—H. A. Lewis, St. Louis, MO
It was neither bad enough to criticize nor good enough to praise, but
you're right, we should have said something about it.
It was, in fact, much better than that of previous Dyna preamps. In
our sample, the maximum balance change through the volume control's
entire rotational range was a shade under 2½dB, and was no more than
2dB through the normal operating range of 9 to 2 o'clock.—J. Gordon Holt
Possibly, our sample PAT-4 did have "a noisy front- end transistor" (see "Manufacturer's Comment") but since both channels were equally noisy when using the high-level phono inputs, and since noise was extremely low when using the low-level inputs, we did not get the impression that we were testing a defective sample. Dynaco offered us the schematic for an input equalizer like the one we tried to put together, except that this one works. We accept the offer with many thanks. Further Thoughts, from June 1970 (Vol.2 No.10)
In our report on the Dyna PAT-4 preamplifier, we stated that we were unable to tell whether the unit was in or out of circuit when we fed a signal to one of its high-level inputs and then bypassed it entirely. This is no longer the case.
