I've been also rocking Mountain view. Ill maybe try austin after and slowly work myself up to norwood. I soldered the pot on ishikawa so need to learn distorsion measuring before trying it.
Just a short question: is it required to readjust the DC offset after putting in another IPS card, in my case Tucson instead of Mountain View? (@checkulater no Austin, my mistake)
Many thanks in advance.
Many thanks in advance.
I acctually checked ofset and it was ok.
The austin has lovely sound but im missing something i think. Ill give it a week before i change
Its super musical and i love the sound but there is something in the soundstage i think. Im not really good at describing sound. I love the sound of both mountain view and austin. Wish i could change the inputs on the fly.
I just wanted to say that i listen to all kind of music and just feel that for some reason blues is really great with the Austin. It really shines there.
Hi, now I switched from the Mountain View to the Tucson - and wow what a difference. Very clear and open sound, maybe even more detailed, the highs are much finer without being superficial, the bass seems to be more controlled. And the mids...great clarity, crisp, much better overall for me. Mountain View is much calmer, even a bit duller by comparison. It's certainly also a matter of taste (I listen to almost all types of music), but the Tucson is a revelation for me. Many thanks @Mark Johnson for this IPS.
PS: I use the LT1122 in the Tucson.
PS: I use the LT1122 in the Tucson.
Congratulations, the LT1122 is an excellent choice. If you ever try "IPS7" (see post #4 of this thread), LT1122 works well there, too.
Thanks Mark! This was an almost forced choice as the original op amp won't be available until next year or so. Yes, I plan to build all IPS cards now... contrary to my original plans, but it's great fun. Next is Norwood, I already have all the parts except for the buffer, which will be delivered at the end of November, hopefully. It will be my first smd work, I'm excited.
Referring back to MJ’s post #101, where he describes the Austin daughterboard:
And given that the originally specified (per the Austin schematic) ZTX Super E-line transistors are currently out of stock at Mouser, may I use these NPN and PNP substitutes?:
NPN:
https://www.mouser.com/c/semiconductors/discrete-semiconductors/transistors/bipolar-transistors-bjt/?q=BJT NPN Super E-line&instock=y
PNP:
https://www.mouser.com/c/semiconductors/discrete-semiconductors/transistors/bipolar-transistors-bjt/?q=BJT PNP Super E-Line&instock=y
Thank you!
Anand.
And given that the originally specified (per the Austin schematic) ZTX Super E-line transistors are currently out of stock at Mouser, may I use these NPN and PNP substitutes?:
NPN:
https://www.mouser.com/c/semiconductors/discrete-semiconductors/transistors/bipolar-transistors-bjt/?q=BJT NPN Super E-line&instock=y
PNP:
https://www.mouser.com/c/semiconductors/discrete-semiconductors/transistors/bipolar-transistors-bjt/?q=BJT PNP Super E-Line&instock=y
Thank you!
Anand.
All six of the bipolar junction transistors on Austin need to be high voltage (>75V) and high beta, as noted on the circuit schematic.
IN ADDITION, I strongly recommend selecting output transistors (Q5 and Q6) which are high voltage, high beta, and the lowest possible Theta-JA (thermal resistance from junction to ambient). In TO-92 style packages, that means either Zetex super E-Line devices, OR Motorola/Fairchild/OnSemi/Toshiba devices in the TO-92L "long boy" package.
If you don't mind finagling the pins a little bit to make everything fit into the PCB drilled holes, medium power transistors in the TO-225 package with metal slug, are even better. TO-126 without the metal slug are nice too. Maybe you'll find a few that fit all of the criteria, (including the most important criterion: It Must Please YOU), in (this list). I slapped it together in 20 seconds so there may be omissions or errors, therefore be cautious, be skeptical, and double-check.
Beware: there are plenty of E-Line transistors that don't go all the way up to 75 volts. The 688 is only good to twelve volts (!).
Finally, you could do some mechanical what-if sketches to estimate whether the TO-92 heatsink (!!) used in the diyAudio Noir headphone amplifier, might possibly fit Q5 and Q6 of Austin without clanking into nearby components. Check the clearance in all three dimensions, as I recall it was surprisingly tall. Download attachment #3 of Noir post #1.
_
IN ADDITION, I strongly recommend selecting output transistors (Q5 and Q6) which are high voltage, high beta, and the lowest possible Theta-JA (thermal resistance from junction to ambient). In TO-92 style packages, that means either Zetex super E-Line devices, OR Motorola/Fairchild/OnSemi/Toshiba devices in the TO-92L "long boy" package.
If you don't mind finagling the pins a little bit to make everything fit into the PCB drilled holes, medium power transistors in the TO-225 package with metal slug, are even better. TO-126 without the metal slug are nice too. Maybe you'll find a few that fit all of the criteria, (including the most important criterion: It Must Please YOU), in (this list). I slapped it together in 20 seconds so there may be omissions or errors, therefore be cautious, be skeptical, and double-check.
Beware: there are plenty of E-Line transistors that don't go all the way up to 75 volts. The 688 is only good to twelve volts (!).
Finally, you could do some mechanical what-if sketches to estimate whether the TO-92 heatsink (!!) used in the diyAudio Noir headphone amplifier, might possibly fit Q5 and Q6 of Austin without clanking into nearby components. Check the clearance in all three dimensions, as I recall it was surprisingly tall. Download attachment #3 of Noir post #1.
_
Attachments
Mark,
Thanks again for the guidance. I revised my search criteria, knowing that the Austin board is quite compact, as such I ruled out TO-225 and TO-126's (at least for now). I ruled in TO-92L "long boy" and of course Zetex super E-Line devices but with the additional criteria of high voltage (>75V) and high beta. Getting the lowest possible Theta-JA has proven to be somewhat of a challenge. So with regards to the TO-92L variety, here is what I came up with that is in stock at Digikey.
The 2 that interest me the most are KSA1013YTA (PNP) and KSA2383YTA (NPN). They are at 160V, and the "Y" variety has the highest beta. I also found the heatsink you alluded to, the Aavid 575200B00000G which is rather tall!
For the TO-126 types, I rather like the TTA004B and TTC004B; they also seem to be good substitutes in the emitter output stages of Waynes BA2018 pre.
Let me know if I am getting close...
Best,
Anand.
Anand, see whether you agree with this statement: "An artful dodger can read the Toshiba TTA004B datasheet cleverly, with great cunning, and from it deduce that Theta-JA is 75 degrees C per watt. Which is a hellll of a lot better than the KSA1013Y in the TO-92 long body package".
Also scan your long term memory to recall when you yourself assembled a Noir headphone amp. It had a TO-92 packaged device "Q71" with a heatsink. Ask yourself "Why is there a dotted rectangle on the PCB silkscreen adjacent to Q71?". When you get the answer, say Eureka.
_
Also scan your long term memory to recall when you yourself assembled a Noir headphone amp. It had a TO-92 packaged device "Q71" with a heatsink. Ask yourself "Why is there a dotted rectangle on the PCB silkscreen adjacent to Q71?". When you get the answer, say Eureka.
_
Attachments
Yup! 139 degC/watt (KSA1013Y) vs 75 degC/watt (TTA004B), essentially a no brainer.
Thanks,
Anand.
Thanks,
Anand.
ZTX696B and ZTX795A are both available at Digi-Key, 1800+ and 14, respectively
Yeah, they are already in my parts list order, I was just looking at other options for Q5, Q6 😉
Best,
Anand.
Hi Mark,
I was wondering if the Cedarburg/AD797 input stage could also be used as a line stage preamplifier before power amps as the BA-3 front-end was successfully used.
The reason is that we see often AD797s being used most in Phono stages, but hardly as line stage for CD players, DACs, or other sources... Thanks.
Cedarburg is an M2x input stage board, and it exactly performs the one specific function which M2x requires: it's a unity gain buffer. Cedarburg cannot be configured to have any gain other than +1.00. Cedarburg requires bipolar supplies reasonably close to +23V and -23V.
That doesn't sound to me like a useful section of a line stage preamplifier.
That doesn't sound to me like a useful section of a line stage preamplifier.
you need an iron too maybe with some nikel on it
Hi Mark,
I was wondering if the Cedarburg/AD797 input stage could also be used as a line stage preamplifier before power amps as the BA-3 front-end was successfully used.
The reason is that we see often AD797s being used most in Phono stages, but hardly as line stage for CD players, DACs, or other sources... Thanks.