Robert,
this is just a hunch. Did you try turning down the gain by dropping the size of R2. Maybe just try quickly wiring in another resistor in parallel ti drop the gain a bit - try maybe a 500R or something like that. You can do it just with jumper wires even. Its worth trying to see if dropping the gain helps drop the RFI a bit.
Fran
this is just a hunch. Did you try turning down the gain by dropping the size of R2. Maybe just try quickly wiring in another resistor in parallel ti drop the gain a bit - try maybe a 500R or something like that. You can do it just with jumper wires even. Its worth trying to see if dropping the gain helps drop the RFI a bit.
Fran
hi Fran
Thanks for the good help so far
I will try the parallel resistor
is that 500 ohm parallel with r2? this is now 1000 ohm
and will also try to make a whole new shielding around my phono cable
Robert
Thanks for the good help so far
I will try the parallel resistor
is that 500 ohm parallel with r2? this is now 1000 ohm
and will also try to make a whole new shielding around my phono cable
Robert
No, if you put it in parallel it will be (R1xR2)/(R1+R2)=X
which if the values for the resistors are 1200R and 500R would work out at 352R.
This is below the 500R that RJM recommended - but this is only a test. So just wire it with jumper leads or something and just see if it make a difference.
If it works you can try substituting in higher values to get more gain. For example, using a 1K in parallel will give you 545R.
Fran
BTW a good link for calculating R in parallel:
http://www.1728.com/resistrs.htm
which if the values for the resistors are 1200R and 500R would work out at 352R.
This is below the 500R that RJM recommended - but this is only a test. So just wire it with jumper leads or something and just see if it make a difference.
If it works you can try substituting in higher values to get more gain. For example, using a 1K in parallel will give you 545R.
Fran
BTW a good link for calculating R in parallel:
http://www.1728.com/resistrs.htm
I've also been experimenting with R2 values lately. My soldered (permanent) R2 value is 900 and I have installed a jumper bridge to add parallel values for experimentation - I am liking maybe 900 + 2200 which is about 600 total, however I have only tried only this combination.
I'm having some hum - maybe grounding? Not easy to systemise.
Cheers to all,
MV
I'm having some hum - maybe grounding? Not easy to systemise.
Cheers to all,
MV
I opened up mine again today.
I have dual mono, with Tx in a separate case. Power brought via 3 core cable to 2 XLR jacks. + and - go to the boards, COM is connected to COM on the boards and GND on the input RCA sockets. COM is also connected to the arm grounding point. If you have a metal case, use uninsulated RCA jacks for input but insulated ones for output.
Using a Benz L2, output 0.35mV, a figure of 350R for R2 still gives lots of gain for the preamp.
Fran
I have dual mono, with Tx in a separate case. Power brought via 3 core cable to 2 XLR jacks. + and - go to the boards, COM is connected to COM on the boards and GND on the input RCA sockets. COM is also connected to the arm grounding point. If you have a metal case, use uninsulated RCA jacks for input but insulated ones for output.
Using a Benz L2, output 0.35mV, a figure of 350R for R2 still gives lots of gain for the preamp.
Fran
hello do you hear the hum on normal listening level ?mavallarino said:
the fixed resistor on mine Phonoclone limited is 1000 ohm
the gain is perfect with the denon dl103 that i use
a little less is also good but not much
Robert
Fran i stay buzzy with this amp.....
I found that the hem reduce much as i touch the phono cable only in the middle with 2 hands about 20 cm distance between my hands than de hum is almost gone on listening level.
When i touch it with 1 hand the hum gets more.
When i use my 2 hands in the begin and end of the cable gives no effect
i must touch it in the middle this works!
The phono cable is schielded and have a plasic cover over the schielding braid i do not touching any metal
I also wraped the cable in alluminium foil and made some grounding connetions but this gives no effect
when i toch the allu foil with 1 hand it hums more again and if i go with my other hand to the foil 5 cm before i touch it the humm ruduce also very much.
I tryed also ferite rings but has also no effect
Robert
I found that the hem reduce much as i touch the phono cable only in the middle with 2 hands about 20 cm distance between my hands than de hum is almost gone on listening level.
When i touch it with 1 hand the hum gets more.
When i use my 2 hands in the begin and end of the cable gives no effect
i must touch it in the middle this works!
The phono cable is schielded and have a plasic cover over the schielding braid i do not touching any metal
I also wraped the cable in alluminium foil and made some grounding connetions but this gives no effect
when i toch the allu foil with 1 hand it hums more again and if i go with my other hand to the foil 5 cm before i touch it the humm ruduce also very much.
I tryed also ferite rings but has also no effect
Robert
Yes, I have seen that too.
I don't know how to solve the problem so that it doesn't happen - but you can lessen it so that it doesn't annoy any more.
Try and route the cables so that you get much less hum. Turn up your volume so that the hum is loud. Then move around each cable until the hum is smallest. Use cable ties or similar to hold the cables in place.
I know that this is not the best solution - there must be a good explanation why this circuit is so prone to RFI problems. Somehow the interconnect to the amp is acting as an antenna.
I will post over in the SS forum and see can anyone help.
Fran
I don't know how to solve the problem so that it doesn't happen - but you can lessen it so that it doesn't annoy any more.
Try and route the cables so that you get much less hum. Turn up your volume so that the hum is loud. Then move around each cable until the hum is smallest. Use cable ties or similar to hold the cables in place.
I know that this is not the best solution - there must be a good explanation why this circuit is so prone to RFI problems. Somehow the interconnect to the amp is acting as an antenna.
I will post over in the SS forum and see can anyone help.
Fran
here is a link to the post about the RFI and shielding:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=116298
There is a suggestion to add a cap across the inputs, hot to chassis ground. That would be worth trying I think.
Maybe do a search on this thread as well - I think I remember something from earlier on in the thread about someone using caps like this. Can't remember what the outcome was though.
Fran
http://www.diyaudio.com/forums/showthread.php?s=&threadid=116298
There is a suggestion to add a cap across the inputs, hot to chassis ground. That would be worth trying I think.
Maybe do a search on this thread as well - I think I remember something from earlier on in the thread about someone using caps like this. Can't remember what the outcome was though.
Fran
tube 300:
See this:
http://www.diyaudio.com/forums/showthread.php?postid=667413#post667413
He adds a 220pF between pins 2 and 3 of the first op amp stage I think and it solves his problem. Could you try that? I won't get at this for a few days. If it works, I think I will do it to both of mine as well.
Pin out here:
http://www.analog.com/images/Product_Descriptions/510639605OP37_fbl.gif
Fran
See this:
http://www.diyaudio.com/forums/showthread.php?postid=667413#post667413
He adds a 220pF between pins 2 and 3 of the first op amp stage I think and it solves his problem. Could you try that? I won't get at this for a few days. If it works, I think I will do it to both of mine as well.
Pin out here:
http://www.analog.com/images/Product_Descriptions/510639605OP37_fbl.gif
Fran
Hello to all,
I am away from home in these days so I am unable to have the time to resolve and listen.
woodturner-fran, do you know if they use OP37 or OP27? I have thought of this idea as well but I wasn't sure of the direction and the values.
I don't have enough time to do all these little projects and modify. I will report again when I try these suggestions.
Thanks and kind regards,
MV
I am away from home in these days so I am unable to have the time to resolve and listen.
woodturner-fran, do you know if they use OP37 or OP27? I have thought of this idea as well but I wasn't sure of the direction and the values.
I don't have enough time to do all these little projects and modify. I will report again when I try these suggestions.
Thanks and kind regards,
MV
vsps w/psu in same box
Does anybody have any ground scheme suggestions for building the VSPS with the PSU in the same chasis?
Does anybody have any ground scheme suggestions for building the VSPS with the PSU in the same chasis?
Re: vsps w/psu in same box
Please have a look at the nude shot of my implementation within this thread. Faint hiss only at full volume.
jagrifen said:
Please have a look at the nude shot of my implementation within this thread. Faint hiss only at full volume.
Hi there!
I just wanted to update my situation and ask a question.
I had a bass problem with my phonoclone.. it was really bass shy.
I felt it was a problem with C1/C2 capacitor values, which it was.
I then ordered the correct (and matched) value caps from Parts connection, also using the recommended brands in the building instructions (blackgate etc)
I have started burning them in. and yes, there is bass!
My only question is.. because the caps leads for C1 and C2 were too big to get through the board and I didn't have a drill handy, I just cut the leads short, bent them, and soldered them snug to the underneath (track side) of the board.
Would this cause any performance degradation? I can't really hear anything wrong so I am assuming it isn't, but please correct me if I am wrong. Thanks!!
I just wanted to update my situation and ask a question.
I had a bass problem with my phonoclone.. it was really bass shy.
I felt it was a problem with C1/C2 capacitor values, which it was.
I then ordered the correct (and matched) value caps from Parts connection, also using the recommended brands in the building instructions (blackgate etc)
I have started burning them in. and yes, there is bass!
My only question is.. because the caps leads for C1 and C2 were too big to get through the board and I didn't have a drill handy, I just cut the leads short, bent them, and soldered them snug to the underneath (track side) of the board.
Would this cause any performance degradation? I can't really hear anything wrong so I am assuming it isn't, but please correct me if I am wrong. Thanks!!
Hi,kaban said:
there should be no discernible performance loss due to the very slightly longer cap leads.
But, will the leads fatigue with vibration? Consider securing the cap body to the PCB.
I think once theres good contact you should be ok - having said that be aware that you don't have a good mechanical joint so the board (and more to the point, the trace on the board) won't stand up to much handling. Verify thats its working OK and get it into a case. Use some silicone or similar to hold the bigger caps to the board.
Fran
Fran
Re: Re: vsps w/psu in same box
Arnoldc, Could you please link to those pics, I am not able to find them within this thread. Thanks!
arnoldc said:
Arnoldc, Could you please link to those pics, I am not able to find them within this thread. Thanks!
Hi and thanks for your valuable feedback!
I have secured the caps to the underside of the board with a glue gun for now, and double checked the connections to the traces both visually and with a multimeter and all seemed to check ok.
I am now just burning the phonoclone in... it does sound nice! I am wondering now if it isn't a little shy in the tops!! It might be me...
I am not going to get concerned until I give them a good couple of weeks of playing, and listening to many different vinyl sources.
I have followed all specs and recommendations to the letter - except for the power transformer. I have a small power transformer (the idea being that as it was in a "test" phase I didn't want to pay for an expensive one then). It is the next part of the project to be upgraded, once I get time (and money!)
My cart is a Denon- DL103 fitted on a Project III debut turntable. I got the larger counterweight installed on the arm because the original counterweight only holds up to 5 grams (from memory) and the Denon is a bit larger.
I must admit the amount of detail the DL103 plus phonoclone gives me compared to the original Ortofon cart is amazing! Everything sounds really crisp and the stereo field is quite wide.. instruments have their own position, cymbals really sound like cymbals and everything is so.. precise??? without loosing too much human-ness.
It's been really enjoyable rediscovering my LP collection, and it's funny but I do prefer some of the vinyl masters compared to some CD releases - they do sound better to my ears... especially compared to early CD releases when the masters were so bad. I guess that is why I love to build a project like the phonoclone! It means accessible high quality vinyl listening pleasure for a fraction of the price!
I have secured the caps to the underside of the board with a glue gun for now, and double checked the connections to the traces both visually and with a multimeter and all seemed to check ok.
I am now just burning the phonoclone in... it does sound nice! I am wondering now if it isn't a little shy in the tops!! It might be me...
I am not going to get concerned until I give them a good couple of weeks of playing, and listening to many different vinyl sources.
I have followed all specs and recommendations to the letter - except for the power transformer. I have a small power transformer (the idea being that as it was in a "test" phase I didn't want to pay for an expensive one then). It is the next part of the project to be upgraded, once I get time (and money!)
My cart is a Denon- DL103 fitted on a Project III debut turntable. I got the larger counterweight installed on the arm because the original counterweight only holds up to 5 grams (from memory) and the Denon is a bit larger.
I must admit the amount of detail the DL103 plus phonoclone gives me compared to the original Ortofon cart is amazing! Everything sounds really crisp and the stereo field is quite wide.. instruments have their own position, cymbals really sound like cymbals and everything is so.. precise??? without loosing too much human-ness.
It's been really enjoyable rediscovering my LP collection, and it's funny but I do prefer some of the vinyl masters compared to some CD releases - they do sound better to my ears... especially compared to early CD releases when the masters were so bad. I guess that is why I love to build a project like the phonoclone! It means accessible high quality vinyl listening pleasure for a fraction of the price!