While I have the board of DISPRE-II coming to me, last night I happened to test direct feeding Aleph 3 with my DAC (Audio-GD Ref-7) via RCA. And I was so pleased with the result. Even though I have to use Win 7's volume control to reduce the volume (using about 5~10% level, which may be bad for SQ due to significant digital volume control), the sound was still very nice. I got further smoother treble and more body, and very transparent, clear, well presented midrange. I knew my listening volume must be high since the sound was so clean and smooth that high volume did not bother me at all. I wasn't paying too much attention to bass since I was already quite surprised by the improvement I heard.
This result makes me very interesting in passive preamp such as B1 now. I was afraid that the gain may be too low in the past, but this test prove me wrong. I read a lot about passive volume control such as Luminous Axiom and realized its issues of impedance matching, especially with A3. So it seems B1 is perfect solution for me (with just a quick read at Pass DIY). Before I bit the bullet and jump for "another" project, I'd like to hear your suggestions (or warning) again (along the passive amp route).
Thanks!
This result makes me very interesting in passive preamp such as B1 now. I was afraid that the gain may be too low in the past, but this test prove me wrong. I read a lot about passive volume control such as Luminous Axiom and realized its issues of impedance matching, especially with A3. So it seems B1 is perfect solution for me (with just a quick read at Pass DIY). Before I bit the bullet and jump for "another" project, I'd like to hear your suggestions (or warning) again (along the passive amp route).
Thanks!
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Given that the Aleph 3 has 20dB gain and is only 2 x 30W into 8 Ohm, too much preamplification of a modern digital (2V) source will cause clipping pretty soon. Zero gain is not such as bad idea at all!
If you decide on building a B1 (it is great; I have an original FirstWatt B1 sitting in front of me) there are a few considerations:
Input selection:
- manual switching (as in the original)?
- with relays (remote controlled?)
- potentiometer(s) (as in the original)?
- stepped attenuators?
- LDR based solution?
- remote controlled?
I would suggest to build one using a simple (alps?) pot or stepped attenuator, using decent, but not over-the-top, caps (Clarity Caps or similar) but leaving enough space to enable upgrading to an LDR and relay based volume control and I/O selection later.
You can obtain the PCB from Pass Labs through the www.passdiy.com site, together with matched jfets.
The other option is the DCB1. I have not heard it so cannot comment.
Good luck!
Albert
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Yes, I am pondering whether to go for B1 or DCB1. And exactly as you described, using humble pot first and then upgrade to LDR type. I only need one input and manual control at this moment.
I was just overwhelmed by the 230 pages of DCB1 build thread. And there seems to be also some variant (Hypnotize version??) Do I really need to read through the whole thread to get all the details? or is there somewhere more concise note?
Also, I would appreciate some hint to get good matched JFET. Some posts mentioned about Spencer. Is he a diyAudio member? As you can see, I am just trying get some orientation.
Any points to the right direction would be appreciated.
Thanks!
Puck
I was just overwhelmed by the 230 pages of DCB1 build thread. And there seems to be also some variant (Hypnotize version??) Do I really need to read through the whole thread to get all the details? or is there somewhere more concise note?
Also, I would appreciate some hint to get good matched JFET. Some posts mentioned about Spencer. Is he a diyAudio member? As you can see, I am just trying get some orientation.
Any points to the right direction would be appreciated.Thanks!
Puck
Yes, I am pondering whether to go for B1 or DCB1. And exactly as you described, using humble pot first and then upgrade to LDR type. I only need one input and manual control at this moment.
I was just overwhelmed by the 230 pages of DCB1 build thread. And there seems to be also some variant (Hypnotize version??) Do I really need to read through the whole thread to get all the details? or is there somewhere more concise note?
Also, I would appreciate some hint to get good matched JFET. Some posts mentioned about Spencer. Is he a diyAudio member? As you can see, I am just trying get some orientation.
Thanks!
Puck
Basically they are the same thing, mez version has multiple inputs with multiple relays, Hypn. version does not, but seems to be heavier made with an eye to really cranking the juice for the ultimate hot rod version.
Russellc
Yes, I am pondering whether to go for B1 or DCB1. And exactly as you described, using humble pot first and then upgrade to LDR type. I only need one input and manual control at this moment.
I was just overwhelmed by the 230 pages of DCB1 build thread. And there seems to be also some variant (Hypnotize version??) Do I really need to read through the whole thread to get all the details? or is there somewhere more concise note?
Also, I would appreciate some hint to get good matched JFET. Some posts mentioned about Spencer. Is he a diyAudio member? As you can see, I am just trying get some orientation.
Thanks!
Puck
I would just buy the PCB + matched JFETs from Pass Labs.
However good the DCB1, for a first attempt the original B1 is very easy to build, few parts, and the hardest to find (the matched JFETs) are supplied by the same reliable source (i.e. Pass Labs).
If you like it, you can always build an "ultimate" version (perhaps DCB1) later.
If I plug CD player directly into Aleph 4 it is just ALIVE there is no other way to descibe it.
The dynamics are fabulous and it is a pleasure to listen to.
With a passive volume control it lost some of its magic so I tried the B1.
Much better than the Pumpkin in terms of ease of use - SILENT in operation. BUT the Pumkpin has an electric edge that just brings everything to life.
The dynamics are fabulous and it is a pleasure to listen to.
With a passive volume control it lost some of its magic so I tried the B1.
Much better than the Pumpkin in terms of ease of use - SILENT in operation. BUT the Pumkpin has an electric edge that just brings everything to life.
The board sold at diyAudio Store is for Mezmerize version only? Where to get the Hypnotize version?
I have built both the B1 and DCB1 and imho the DCB1 is a step up in sound quality[sorry Nelson]. More clarity and openness especially when coupled with an LDR type volume control. Because of the dc offset risk I used capacitors on the output but not the input.
Spencer is a forum member and I believe sells matched fets.
If you want to try something totally different TVC's work extremely well although somewhat more expensive.
Spencer is a forum member and I believe sells matched fets.
If you want to try something totally different TVC's work extremely well although somewhat more expensive.
Marra, you are the man! I just got almost all I need from TeaBag for DCB1. Thanks a bunch for pointing me to the right direction.
Now, I need to read through all the posts about DCB1...
OK, I first finished the Uriah's Lighter Note project. I removed all the high value resistor (1M~20Mohm) so basically I just have LRD as a voltage divider. It sound good and nice.
However, I found that if I use Foobar to output 24-bit (to alleviate some loose of bits by digital volume control) and use Win 7 volume control, the direct output of my Audio-GD's Ref (22 ohm Zout) to Aleph 3 (20k Zin) sound still better. Very smooth high and more realistic live feeling with my Hifiman HE-6 headphone.
This really brings up a question: Does my DAC direct output to Aleph3 has better impedance match and hence better sound?
My Lighter Note has a total resistance in the voltage divider of about 7K ohm (shunt + series).
DCB1 will be my next build. But now I really wonder if I "need" to build it.
Oh, the only complain to DAC-> Aleph3 was the pops made by Foobar when I change FLAC on the fly. Sometimes pops were quite annoying, but other times there were none.
However, I found that if I use Foobar to output 24-bit (to alleviate some loose of bits by digital volume control) and use Win 7 volume control, the direct output of my Audio-GD's Ref (22 ohm Zout) to Aleph 3 (20k Zin) sound still better. Very smooth high and more realistic live feeling with my Hifiman HE-6 headphone.
This really brings up a question: Does my DAC direct output to Aleph3 has better impedance match and hence better sound?
My Lighter Note has a total resistance in the voltage divider of about 7K ohm (shunt + series).
DCB1 will be my next build. But now I really wonder if I "need" to build it.
Oh, the only complain to DAC-> Aleph3 was the pops made by Foobar when I change FLAC on the fly. Sometimes pops were quite annoying, but other times there were none.
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