X-Altra Line Level Preamp

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#81
hadihf, I’ve not used any board interconnects on this preamp. If you thoroughly test the modules before final wiring up you should be ok.

I’ve only had a reliability problem with one of my amps many years ago (blew the bass units in my speakers) because it had extensive‘development’ mods to it - all the others have been really reliable in operation.
🙂
 
#85
Yes, a tone stage and IR remote control. My thoughts exactly. I was thinking the variable frequency stage designed by Mr. Self would be a good choice, and there is my own IR remote control stage that has the stepper driver circuit for a 47 step control.

That leaves the question of a balance control. I have no good arguement either way, but my personal choice is to leave it out, based on seldom using the control on equipement that had one other than to quickly check if both channels were working.
 
#86
No plans to add a balance control at this stage. For the full function unit, the remote control will be added and that's it. If you want a tone control, it will require moving up to a larger housing. Remote will be up and runnung with appropriate front panel in about 4-6 weeks. It uses a standard Apple TV Remote
 
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#91
Bonsai said:
To drive a sub bass or a 2nd Amp. I run a 240 W and a 15 W class A and then a sub bass. I only use one of the amps at one time but it means no need to swap cables or build a switch box.
Click to expand...
Thanks Andrew.

There are two Aux outputs. One is switched and other in none switched. Which one is used for bass or a 2nd Amp?

I think it is the none switched one..
 
#93
As promised a week or two back, here are the X-Altra Mini II discrete line stage measurements using the TI JFE2140 dual JFETS. The performance is as good if not a bit better than the LSK389B devices specified in the BOM, and they will also work just as well in the X-Altra MC/MM EQ Preamp published in audioXpress last year.

🙂
 

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#95
hadihf said:
Thanks Andrew.

There are two Aux outputs. One is switched and other in none switched. Which one is used for bass or a 2nd Amp?

I think it is the none switched one..
Click to expand...
Sorry - late reply here. Yes - that's how I've hooked mine up. The non-switched* aux output goes to my B&W sub bass which has an auto trigger facility on it and does not generate switch on thumps when powering up or down. The unbal switched output goes to my kx2-Amp, and the switched balanced output goes to my 240W per channel Model 1721 power amp. I only run one of the amps at a time because I've gopt dedicated speakers for each amp. Anyway, no more swapping cables around - everything is handled by the X-Altra Mini II

*by switched we mean equipped with a power up/down mute facility via relays.
 
#97
Unfortunately, the board only takes the SOIC or the TO71 6L metal can package - it wont take the Toshiba in-line SIP package. However, you can now also use the TI JFE2140 (SOIC package) which is a pin for pin improved replacement for the LSK389 and avaiablle from mouser
 
#98
Hi Andrew,

Does the MC amp output around U3 goes to U5 RIAA equalization and further to output J5? I think this happens through jumpers settings a U4.

Is there a jumper map for U4 available?

Sorry for the silly questions. Phono is a new thing for me I am just trying to understand.

Best Regards
Farooq
 
#99
hadihf said:
Hi Andrew,

Does the MC amp output around U3 goes to U5 RIAA equalization and further to output J5? I think this happens through jumpers settings a U4.

Is there a jumper map for U4 available?

Sorry for the silly questions. Phono is a new thing for me I am just trying to understand.

Best Regards
Farooq
Click to expand...


U4 uses 4 jumpers to send the input signal to the MC pre and then to the MM stage or just to the MM stage like this:-

1658667239021.png
 
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