bobsinclar said:I can imagine, I spent all day long playing with them all! and I am now to the point that I have found a very nice sounding result, but sure I won't go far by these means...Should I find a distorsion analyzer?, is that the most desirable gear to look forwhen building amps?
Vince
What values did you end up with?
Thanks
Jim
Dear Nelson,thanks for that advise, I will look for that kind of analyzer, as I'd really like to know how to progress, as it's easy to feel a bit lost at this point
Jim, actually I have attached the last version of the schematic, with the values I ended with, anyway I feel happy as it has no noise or parasitic oscillations, and sounds correct to my ears, but I do not encourage anyone to take it as a serious schematic I am not electronical ingeneer, and suspect this schematic to have multiple anomalies , I really made it as I felt and trimmed everything til ound could come out... I'd be glad if someone would want to try it and bring any modification needed to create something we could work on...
actually the pfirst thing I could point out is that it has too much gain, and also I think that with this trimmings the J fet is a bit close to the edge (about 11mA)...
as a comparasion I will build the BOZ this week end, and will come back with subjective comments .
best regards
Vince
Jim, actually I have attached the last version of the schematic, with the values I ended with, anyway I feel happy as it has no noise or parasitic oscillations, and sounds correct to my ears, but I do not encourage anyone to take it as a serious schematic I am not electronical ingeneer, and suspect this schematic to have multiple anomalies , I really made it as I felt and trimmed everything til ound could come out... I'd be glad if someone would want to try it and bring any modification needed to create something we could work on...
actually the pfirst thing I could point out is that it has too much gain, and also I think that with this trimmings the J fet is a bit close to the edge (about 11mA)...
as a comparasion I will build the BOZ this week end, and will come back with subjective comments .
best regards
Vince
Attachments
Thanks Vince,
I am interested in this for reasons similar to yours. Play with some jfets, a cascode and learn a bit. I was thinking about building something similar when I spotted this thread. I now have something to use for to help me when I build mine. It will be some time before I get to this, I have a backlog.
I did find a circuit for a very simple distortion analyzer. I'm not sure if it is good enough, but it is simple enough that it may be worth trying it.
Here is the link.
http://members.aol.com/sbench102/TubeMisc/notch.gif
Have fun
Jim
I am interested in this for reasons similar to yours. Play with some jfets, a cascode and learn a bit. I was thinking about building something similar when I spotted this thread. I now have something to use for to help me when I build mine. It will be some time before I get to this, I have a backlog.
I did find a circuit for a very simple distortion analyzer. I'm not sure if it is good enough, but it is simple enough that it may be worth trying it.
Here is the link.
http://members.aol.com/sbench102/TubeMisc/notch.gif
Have fun
Jim
Hello Jim,
actually you can go ahead with the last schematic I posted,I have just built the Jfet BOZ ,similar to Nelsons schematic ,(except that I have+ 22V rail PSU),
I thought it would be a nice comparaison to highlight the sonic differences between the 2 version: Cascoded/not cascoded
as for the objective part:
the two preamps show quite the same square and sine waves figures all around the audio range(same very tiny roll off at top end...) squares look good and very similar too...
Good point at first sight
Now concerning the sound, and this is the subjective part, so I will try to be objectively subjective
the Jfet Boz sounds really live, dynamic and has strong bottom, everything to be pleased...the only drawback would be that with my speakers that use Horn drivers, a softer mids and highs would be desirable...as it can become a bit edgy when played loud...
the preamp is not to blaim there anyway, as I know that the speakers could have been a bit dampen in that region...
Now with the cascoded version, the sound still have strong bottom , but highs and mids really feel like more liquid (with still a bit of an edgy character coming from the speaker...)
this lead me to think that the cascoded could be and improvement over the single version, but I will make furthers listnings test, on other speakers soon...
Best regards
Vince
actually you can go ahead with the last schematic I posted,I have just built the Jfet BOZ ,similar to Nelsons schematic ,(except that I have+ 22V rail PSU),
I thought it would be a nice comparaison to highlight the sonic differences between the 2 version: Cascoded/not cascoded
as for the objective part:
the two preamps show quite the same square and sine waves figures all around the audio range(same very tiny roll off at top end...) squares look good and very similar too...
Good point at first sight
Now concerning the sound, and this is the subjective part, so I will try to be objectively subjective
the Jfet Boz sounds really live, dynamic and has strong bottom, everything to be pleased...the only drawback would be that with my speakers that use Horn drivers, a softer mids and highs would be desirable...as it can become a bit edgy when played loud...
the preamp is not to blaim there anyway, as I know that the speakers could have been a bit dampen in that region...
Now with the cascoded version, the sound still have strong bottom , but highs and mids really feel like more liquid (with still a bit of an edgy character coming from the speaker...)
this lead me to think that the cascoded could be and improvement over the single version, but I will make furthers listnings test, on other speakers soon...
Best regards
Vince
Hi There
I am now making some stereo listning tests (the previous were in mono mode...I had only one channel made of each preamp at that time...)
and here I will be less objective, I am just stunned by the airy character of each of these preamps, the stereo effects and sound stage are just great, wide, focused and dynamic with very strong bass...
the two(cascoded or not) still have the same sonic signature(the J fet )but eachof them does exceed the quality of all the preamps I had over here(SAE/NAKAMICHI etc...) actually I don't even remember having listened to a similar wide soundstage anywhere else...
again a big thank to M PASS
Vince
I am now making some stereo listning tests (the previous were in mono mode...I had only one channel made of each preamp at that time...)
and here I will be less objective, I am just stunned by the airy character of each of these preamps, the stereo effects and sound stage are just great, wide, focused and dynamic with very strong bass...
the two(cascoded or not) still have the same sonic signature(the J fet
)but eachof them does exceed the quality of all the preamps I had over here(SAE/NAKAMICHI etc...) actually I don't even remember having listened to a similar wide soundstage anywhere else... again a big thank to M PASS
Vince
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.