Just think I remembered that the CCS current is 3mA, not 30mA
Which if I remember correctly will read as a drop of 30mV over R1 and 2, and not 300. Wayne describes this in the video from BAF. Just measure as proposed and see what you get. An unstable reading or no drop at all is what you don’t want 🙂
It is a range. If I remember correctly, Wayne likes the preamp at 20v, most others seem to like it at 18v. Either way it is a great preamp!
Dirk is playing around with Waynes Line Stage...
I made my own pcbs with slightly more space - easier to measure.
Exchanged the TOSHIBA 2SK209 with ONSEMI 2SK3557-6-TB-E. Had to adjust a few resistor values -
more current to those tiny JFets. Running at slightly above 34° C.
Exchanged the Fairchilds KSA992/KSC1845 with ZETEX ZTX851/951. Running at 35° - 37°C.
Outputtransistors are TOSHIBA TTA/TTC004B. Running at 29° C. Perhaps room for more bias...
I have some hum. But no wonder with those wild cabling for testing. And the preamp/PSU is on the wood board.
The sound is great with my IXYS-Mosfet-monoblocks.
I am listening... 🎼🎧
Cheers
Dirk 🙂
I made my own pcbs with slightly more space - easier to measure.
Exchanged the TOSHIBA 2SK209 with ONSEMI 2SK3557-6-TB-E. Had to adjust a few resistor values -
more current to those tiny JFets. Running at slightly above 34° C.
Exchanged the Fairchilds KSA992/KSC1845 with ZETEX ZTX851/951. Running at 35° - 37°C.
Outputtransistors are TOSHIBA TTA/TTC004B. Running at 29° C. Perhaps room for more bias...
I have some hum. But no wonder with those wild cabling for testing. And the preamp/PSU is on the wood board.
The sound is great with my IXYS-Mosfet-monoblocks.
I am listening... 🎼🎧
Cheers
Dirk 🙂
Attachments
A very cheap one I bought from a diyaudio member a couple of years ago. It has no brand name. It sounded fine untill I heard the Muses.
I am getting to the next round with Waynes Line Stage:
this time I use another very low noise JFet, the ONSEMI 2SK2394 (Q1-Q4). It has lower noise than the BF862.
Matched those tiny JFets.
And matched the BJTs in the other stages. So I will see how it sounds. Have to solder a little bit....
The other version with the SK3557 sounds great but neeeds some minor adjustment.
I will also use my external MUSES-volume control. First test is always done with an ALPS RK27.
Cheers
Dirk 😉
this time I use another very low noise JFet, the ONSEMI 2SK2394 (Q1-Q4). It has lower noise than the BF862.
Matched those tiny JFets.
And matched the BJTs in the other stages. So I will see how it sounds. Have to solder a little bit....
The other version with the SK3557 sounds great but neeeds some minor adjustment.
I will also use my external MUSES-volume control. First test is always done with an ALPS RK27.
Cheers
Dirk 😉
Attachments
I completely agree. Academy Audio provided a great product and services, and my BA2018 sounds terrific. There are other Muses options but I'd buy again from AA without a second's thought.
Regards.
I have a question
I have the q8 & q10 with ksa1845 & ksa992 and alternatives ttc004 & tta004
what is the best option?
thanks
I have the q8 & q10 with ksa1845 & ksa992 and alternatives ttc004 & tta004
what is the best option?
thanks
Hello takis1969,
the bigger outputtransistors make sense, if you want to drive headphones ( it is a very good headphoneamp!) or you need a lot of 'drive' at the output of the preamp.
It doesn't harm to use the big ones or the smaller BJTs.
I have built 5 versions of Waynes Line Stage and prefer the Toshiba TTA/TTC004B - combo.
But this is my personal preference.
Cheers
Dirk 😉
the bigger outputtransistors make sense, if you want to drive headphones ( it is a very good headphoneamp!) or you need a lot of 'drive' at the output of the preamp.
It doesn't harm to use the big ones or the smaller BJTs.
I have built 5 versions of Waynes Line Stage and prefer the Toshiba TTA/TTC004B - combo.
But this is my personal preference.
Cheers
Dirk 😉
I switched from the small to the large transistors and didn't notice much of a difference. I can't think of what would be the benefit of using the smaller ones that come with the kit.
If it's me having to choose, I will use the small ones because I like solder fumes so much!