Heathkit AA-32 XTL phono input

[62vauxhall]

Since an AA-32 is a fairly uncomplicated amplifier, is there any reason not to use it's XTL phono input with a line level source?

There is only one 6EU7 tube in the phono section, for MAG phono and to my knowledge, nothing present to create industry equalization on XTL phono. MAG phone either come to think about it.

 

[BinaryMike]

The schematic I have shows different equalization on the CER input, but you could fix that by changing a couple of resistors in each channel to match the TUNER and AUX inputs.

This model uses passive RIAA equalization --- see components attached to the anode of the MAG preamp stage.

 

[Jeff449]

I thought about doing the same exact thing with my AA-32. The mag phono section sounds unremarkable anyway. Reworking both ceramic and mag would give you 2 more line level inputs. One could be connected to a stand alone phono preamp.

 

[tubeactive]

Maybe, the phono stage can be optimized for that amp ? If the passive phono EQ sounds dull, wake up the amp with a better circuit....

 

[Jeff449]

If I could find a schematic of a better circuit that uses the same tube, I would.

 

[AdamAnt316]

Years ago, when I was running a Heathkit AA-151 in my main system, I used the XTAL PHONO input as a line-level input without changing any components. I didn't notice any major issues with the sound vs. the AUX input, though I didn't do any comprehensive comparisons.
-Adam

 

[gadget73]

6EU7 is electrically the same as a 12AX7, so if you find a 12AX7 RIAA stage, that will work. Most use both triodes per-channel. If you've got only a single triode per channel that limits things.