Honestly I think they are simply for show and a simply a gimmick to encourage less knowledgeable people to buy this preamp. It is true that some capacitors generate non-linear distortion but a much better, and smaller option would be polystyrene types.
I don't know whether the ones on this board are particularly accurate, though. It may be for that reason, but it seems that they are there only for snake oil purposes...
I may be wrong though, but the only reason I can think of is accuracy.
I don't know whether the ones on this board are particularly accurate, though. It may be for that reason, but it seems that they are there only for snake oil purposes...
I may be wrong though, but the only reason I can think of is accuracy.
Fair enough.
One thing that the designers could have done was lower the value of the DC decoupling capacitor that comes after the RIAA network in order to introduce a 20Hz roll-off to reduce rumble. I'm rather surprised that they didn't do this as the linearity is not so good and there's the possibility of rumble causing some significant inter modulation distortion in the preamp itself.
10uF is also a little large for a unit with no muting circuit. That's gotta be a big bang when it turns on
.
One thing that the designers could have done was lower the value of the DC decoupling capacitor that comes after the RIAA network in order to introduce a 20Hz roll-off to reduce rumble. I'm rather surprised that they didn't do this as the linearity is not so good and there's the possibility of rumble causing some significant inter modulation distortion in the preamp itself.
10uF is also a little large for a unit with no muting circuit. That's gotta be a big bang when it turns on
.There is NO SNAKE OIL..... SERIOUSLY?? The caps ARE polystyrene.....
I bought the boards ONLY and populated them myself
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BHL kits use RUS PIO caps... my build is exactly that - my build - I selected the caps for better than 0.5% accuracy and better than that matching between channels (I have a wide range of calibrated PS caps - fully tracable - that are kept thermally stable). I have repeatedly stated my build and the choices I made were solely "for the fun of it" and my build has nothing to do with BHL business its a ******* DIY project and thats all it is.
1uF PS caps ARE that big...
1uF PS caps ARE that big...
Fair enough . I'm done with this thread anyway. I'll leave with a list of reasons why reasons why I think the BHL is inferior, though.
1. Very poor power supply rejection, especially for mains frequency ripple, which may be amplified by as much as 30dB at the output.
2. Nowhere near enough headroom. A passive RIAA preamp is only really suited to the domain of valves, where headroom is possibly 100 volts either way. In this case it will be less than 12 or so. This means the preamp will not be able to cope with brief overloads such as clicks and pops that are inherent with phonograph discs. This will result in drop-outs along with clicks. Nasty.
3. Headroom is compromised even further by differences in bias current due to a wide tolerance in the JFETs, Ids typically varies between 2 and 5 mA, resulting in severely compromised output swing.
4. Likewise, gain is also compromised by the wide tolerance range of the FETs used, channel balance will be rather poor to say the least.
5. High output impedance, the already compromised output swing will be further reduced by the input impedance of whatever this preamp is connected to. Connecting a 10K load will reduce the output swing by at least 2dB.
6. No muting circuit. When the preamp is turned on a very loud band or thump will be heard as the output reaches half the supply voltage, in this case maybe even 14V or so. This may even damage some preamps with low supply voltages and no input clamping.
7. Poor linearity. Inherent to the fact that no feedback is used along with the already compromised headroom. Distortion will also be much higher at high frequencies due to distortion in the first stage. Very possibly audible.
8. Paper in oil capacitors. Leaky in a word. Ask anyone who has repaired older equipment. Why they are used in this circuit is a complete mystery to me.
You have been warned ! Do not buy this kit. You can do much better!
. I'm done with this thread anyway. I'll leave with a list of reasons why reasons why I think the BHL is inferior, though.1. Very poor power supply rejection, especially for mains frequency ripple, which may be amplified by as much as 30dB at the output.
2. Nowhere near enough headroom. A passive RIAA preamp is only really suited to the domain of valves, where headroom is possibly 100 volts either way. In this case it will be less than 12 or so. This means the preamp will not be able to cope with brief overloads such as clicks and pops that are inherent with phonograph discs. This will result in drop-outs along with clicks. Nasty.
3. Headroom is compromised even further by differences in bias current due to a wide tolerance in the JFETs, Ids typically varies between 2 and 5 mA, resulting in severely compromised output swing.
4. Likewise, gain is also compromised by the wide tolerance range of the FETs used, channel balance will be rather poor to say the least.
5. High output impedance, the already compromised output swing will be further reduced by the input impedance of whatever this preamp is connected to. Connecting a 10K load will reduce the output swing by at least 2dB.
6. No muting circuit. When the preamp is turned on a very loud band or thump will be heard as the output reaches half the supply voltage, in this case maybe even 14V or so. This may even damage some preamps with low supply voltages and no input clamping.
7. Poor linearity. Inherent to the fact that no feedback is used along with the already compromised headroom. Distortion will also be much higher at high frequencies due to distortion in the first stage. Very possibly audible.
8. Paper in oil capacitors. Leaky in a word. Ask anyone who has repaired older equipment. Why they are used in this circuit is a complete mystery to me.
You have been warned
! Do not buy this kit. You can do much better!I stand by what Ive already said..
BHL openly state that this build IS NOT a high performance build .. it was designed to be a fun experimental platform. Its key that you not take this build too seriously.. it never was... and I never did..
Having said that there are plenty of builders who are confirming that it delivers a very pleasing listening experience - I for one, it easily competes with my CA 651p phono amp -
After all the history of HiFi is LITERALLY built on and indeed accepts that electronics theory and the listening experience hardly ever correlate well and progress has been thru those who have challenged the limitations of text-book theory. Indeed our +10k year civilisation is built on not accepting the status-quo.
At the end of the day it comes down to personal choice and dont forget DIY is about having fun...
Im happy to recommend the BHL build if youre looking for a quick and easy build - in fact check out the new DELUXE MC-MM buffered dual-mono version, Im probably gonna build one now as well as SALAS SIMPLISTIC JFET just for the fun of it..
BHL openly state that this build IS NOT a high performance build .. it was designed to be a fun experimental platform. Its key that you not take this build too seriously.. it never was... and I never did..
Having said that there are plenty of builders who are confirming that it delivers a very pleasing listening experience - I for one, it easily competes with my CA 651p phono amp -
After all the history of HiFi is LITERALLY built on and indeed accepts that electronics theory and the listening experience hardly ever correlate well and progress has been thru those who have challenged the limitations of text-book theory. Indeed our +10k year civilisation is built on not accepting the status-quo.
At the end of the day it comes down to personal choice and dont forget DIY is about having fun...
Im happy to recommend the BHL build if youre looking for a quick and easy build - in fact check out the new DELUXE MC-MM buffered dual-mono version, Im probably gonna build one now as well as SALAS SIMPLISTIC JFET just for the fun of it..
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So, yeah. It's not a HiFi preamp. It's a LoFi effects unit. If, like ClassC, you enjoy listening to seriously compromised audio equipment and have $40+ that you want to flush down the toilet this is the preamp for you!
That's what this forum is all about! Building inferior pieces of equipment. In fact that's the whole point of DIY!
High performance audio? No thanks! I want distortion, horrible overload drop outs and a nice earsplitting bang that might destroy my speakers when I turn on my HiFi. That's just the way I roll !
All the advancements in audio technology have been made by building objectively poor amplifiers and speakers. In fact that's why electrical disc recording never took off! People hated the sound of the better frequency response and lower distortion, which is why we still listen to acoustic gramophones today .
So lets challenge the status quo! I propose that we only listen to music through the telephone for a start !
Now if you will all excuse me I have to visit the doctor to have my tongue surgically removed from my cheek.
That's what this forum is all about! Building inferior pieces of equipment. In fact that's the whole point of DIY!
High performance audio? No thanks! I want distortion, horrible overload drop outs and a nice earsplitting bang that might destroy my speakers when I turn on my HiFi. That's just the way I roll
!All the advancements in audio technology have been made by building objectively poor amplifiers and speakers. In fact that's why electrical disc recording never took off! People hated the sound of the better frequency response and lower distortion, which is why we still listen to acoustic gramophones today
.So lets challenge the status quo! I propose that we only listen to music through the telephone for a start
!Now if you will all excuse me I have to visit the doctor to have my tongue surgically removed from my cheek.
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