I think once the main board and DB's are tested and working fine, it may be an option to solder the DB's to the main board. I've never felt very happy with the wobbly DB's. The cheapy header connectors were not designed to hold a board very tight and rigid without any other support. I've also considered adding support to the top edges of the DB's.
![lXhyd[1].jpg](/community/data/attachments/653/653573-0c68fa6f212f28dd7b5ed19a3f9b40d0.jpg?hash=DGj6byEvKN)
Added some heatsinks to the transistors.
Main board: R141 to 10k
THT: R10 33k, and R11 6k8.
Couldn't get the Vishay Metal film resistors, so found some other Metal film resistors, not as accurate as the Vishay's.
Still waiting for the DACT SMD attenuator.
The cable from the X121 to X111, how do I know what side is to be correct between them?
Main board: R141 to 10k
THT: R10 33k, and R11 6k8.
Couldn't get the Vishay Metal film resistors, so found some other Metal film resistors, not as accurate as the Vishay's.
Still waiting for the DACT SMD attenuator.
The cable from the X121 to X111, how do I know what side is to be correct between them?
Attachments
Done a bit more today.
Attached the AKSA to a timber board, attached the power board, found a previous LED cable, just need to know what resistor is needed for it. Put some PCB headers for the DACT attenuator (it's not here yet)
Just need to sort the power cable to the HP laptop power system, attach some RCA sockets and attach the DACT when it arrives and will see if it works!
Attached the AKSA to a timber board, attached the power board, found a previous LED cable, just need to know what resistor is needed for it. Put some PCB headers for the DACT attenuator (it's not here yet)
Just need to sort the power cable to the HP laptop power system, attach some RCA sockets and attach the DACT when it arrives and will see if it works!
Attachments
For LED, 15k works well. Basically 45v and 15k gives 3mA which is not too blinding bright. 20k could work if you like a little but dimmer intensity.
It depends on the wavelength or color of the LED.
I've used 15k on the board plus an extra 56k in series (on the LED lead) to get a blue LED dim enough for night-time use. PSU is set to 48V.
Ok. have been waiting for the SMD DACT, and still hasn't arrived.
Have and set a Mouser potentiometer 10KOhms 688-RK09L12D0A1W, connected it today.
The pre-amp only works on the right side. Can feel the right side of the THT is warm on the heatsinks, and the the left side is cold.
How do I test where the left side is not connecting or some other mistake.
The sound on the right side sounds good, but if I turn the potentiometer up to the normal volume on my old Musical Fidelity Preamp 3A it crackles in the speaker.
Have and set a Mouser potentiometer 10KOhms 688-RK09L12D0A1W, connected it today.
The pre-amp only works on the right side. Can feel the right side of the THT is warm on the heatsinks, and the the left side is cold.
How do I test where the left side is not connecting or some other mistake.
The sound on the right side sounds good, but if I turn the potentiometer up to the normal volume on my old Musical Fidelity Preamp 3A it crackles in the speaker.
ok, now it is working, and sounds way better compared to my old 1990 Musical Fidelity Preamp 3A
Will order the non Vishay resistors to replace with the Vishays
Are there any of the original parts in my preamp that could be replaced with better parts and make even better sound?
Will order the non Vishay resistors to replace with the Vishays
Are there any of the original parts in my preamp that could be replaced with better parts and make even better sound?
Hello Maf_au
It looks like your Wima MKP4 caps are only 1uF.
In order not to loose low frequency information, I’d start by replacing those with a value closer to 10uF.
Looks like you’ve got a nice build there 🙂
ENJOY!!
Regards,
Vunce
Thanks Vunce.
Had a look and can get 1 pair (2pcs) of Mundorf MCap250 Capacitors 5% 250V 10uF
That should fix that!
Anything else?
Had a look and can get 1 pair (2pcs) of Mundorf MCap250 Capacitors 5% 250V 10uF
That should fix that!
Anything else?
maf_au,
Very nice build there. Your parts are pretty good quality with all Vishay resistors and looks like Panasonic electrolytics. With the 10uF Mundorf input you are pretty much approaching the best it’s going to get. If you want, try changing the feedback resistor for a carbon film - that might make it sound a bit smoother. Other than that, you have a great Preamp. A lot for the great sound comes from the design and topology and the layout by JPS64. Just changing parts on your other preamp will probably not bring you similar levels of sound quality improvement as just using the Aksa Lender even with inexpensive non premium parts.
Very nice build there. Your parts are pretty good quality with all Vishay resistors and looks like Panasonic electrolytics. With the 10uF Mundorf input you are pretty much approaching the best it’s going to get. If you want, try changing the feedback resistor for a carbon film - that might make it sound a bit smoother. Other than that, you have a great Preamp. A lot for the great sound comes from the design and topology and the layout by JPS64. Just changing parts on your other preamp will probably not bring you similar levels of sound quality improvement as just using the Aksa Lender even with inexpensive non premium parts.
The cheap DACT type attenuator finally arrived today. Sounds a bit better than the ALPS Potentiometer. Have them set so can swap them easy to test them.
Still waiting for the Mundorf Caps. Might add some caps (10u0, C1022,C1032) while waiting. If I run the volume up, the sound is crackling!!!
Still waiting for the Mundorf Caps. Might add some caps (10u0, C1022,C1032) while waiting. If I run the volume up, the sound is crackling!!!
Attachments
Wich type of music? Commercial (badly recorded and low/very low DR) or good/very good recording with high/very high DR.
Have you tried a good jazz or classical recording?
DR: dynamic range.
Btw, why not Blue Alps insted the little green RK9?
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Hi maty,
Since adding the DACT type attenuator, have only listen to one CD so far.
Have listened to this CD on our music system over a long time as I have been improving the system over time.
Gillian Welch: Soul Journey - Wikipedia
Don't have any non-CD music, but listen to Jazz, Blues, Classical and a variety but not much pop 🙂
Had to buy the ALPS that was available to me at the time. Don't know the different between blue or green. What is the different to them, and are they better than the DACT attenuator?
Since adding the DACT type attenuator, have only listen to one CD so far.
Have listened to this CD on our music system over a long time as I have been improving the system over time.
Gillian Welch: Soul Journey - Wikipedia
Don't have any non-CD music, but listen to Jazz, Blues, Classical and a variety but not much pop 🙂
Had to buy the ALPS that was available to me at the time. Don't know the different between blue or green. What is the different to them, and are they better than the DACT attenuator?