Re: Re: off topic
thanks roger
that is excetly what I want , a little gain.
which tranformer are you refering to ?
JT-11P-1 or JT-11P4-1-1
Thanks.
😀 😀
sx881663 said:
thanks roger
that is excetly what I want , a little gain.
which tranformer are you refering to ?
JT-11P-1 or JT-11P4-1-1
Thanks.
😀 😀
Transformer advice
I would need to know more about how you plan on using it and approximately what your budget can stand. How about emailing me directly? Please include your name, I like to know who I am helping.
Roger
I would need to know more about how you plan on using it and approximately what your budget can stand. How about emailing me directly? Please include your name, I like to know who I am helping.
Roger
what value of coupling cap ?
what value of coupling cap to use?
"preamp problem Post #6
What is happening is all the low frequency noise from the pre is triggering the protection circuits. You probably noticed woofer cone pumping as well. There are several ways to attack the problem but the more practical ones are to limit the input bandwidth severely in comparison to what it now is. That would be replacing the amp input caps with .047-.1UF. This might be enough to do it. The other thing would be to reduce the time constant of the preamp's power supply to so low to noise can’t pass. This would require 5-10 times more DC filter capacitance being added. This is a better fix as it corrects the real problem, a preamp with low frequency stability issues."
Roger
so what is the right vaule to use ?
2.2UF or .1UF and what kind of cap ?
Thanks.
what value of coupling cap to use?
"preamp problem Post #6
What is happening is all the low frequency noise from the pre is triggering the protection circuits. You probably noticed woofer cone pumping as well. There are several ways to attack the problem but the more practical ones are to limit the input bandwidth severely in comparison to what it now is. That would be replacing the amp input caps with .047-.1UF. This might be enough to do it. The other thing would be to reduce the time constant of the preamp's power supply to so low to noise can’t pass. This would require 5-10 times more DC filter capacitance being added. This is a better fix as it corrects the real problem, a preamp with low frequency stability issues."
Roger
so what is the right vaule to use ?
2.2UF or .1UF and what kind of cap ?
Thanks.
Re: what value of coupling cap ?
In another thread we beat this one to death. The bottom line, with enough mathematic proof for any critic, is that the 2.2uf cap is the best all around value as long as you don’t have low freq. issues with your preamp. The 2.2uf @ 200v Auricap is my personal cap of choice. Besides the UcD usage I use it in my amp 3 as well as an earlier SI.
Years ago I became associated with the makers of the Auricap because of the superiority of there product. Over these same years their caps have significantly improved both measurably and sonically. I recommend them with out reservation and not because I work with Audience (I do) but because it is a superior product at a fair price. Over these same years I have never seen a failure of one of their caps other than leads being pulled off and this one I didn’t understand as it takes a great deal of force to do this. The leads are spot welded; soldered and epoxied therefore they are quite strong. (Yes, a special solder is used!)
Roger
jj2 said:
In another thread we beat this one to death. The bottom line, with enough mathematic proof for any critic, is that the 2.2uf cap is the best all around value as long as you don’t have low freq. issues with your preamp. The 2.2uf @ 200v Auricap is my personal cap of choice. Besides the UcD usage I use it in my amp 3 as well as an earlier SI.
Years ago I became associated with the makers of the Auricap because of the superiority of there product. Over these same years their caps have significantly improved both measurably and sonically. I recommend them with out reservation and not because I work with Audience (I do) but because it is a superior product at a fair price. Over these same years I have never seen a failure of one of their caps other than leads being pulled off and this one I didn’t understand as it takes a great deal of force to do this. The leads are spot welded; soldered and epoxied therefore they are quite strong. (Yes, a special solder is used!)
Roger
roger thanks for the quick reply.
I too have use 2.2 Auricap with me amp3 kit, but for my UCD400 with the pre amp's low freq issues I should use .1UF . right ?
one more stupid question,
with a .1uf cap will it affect the other frequency beside the low?
thanks again.
I too have use 2.2 Auricap with me amp3 kit, but for my UCD400 with the pre amp's low freq issues I should use .1UF . right ?
one more stupid question,
with a .1uf cap will it affect the other frequency beside the low?
thanks again.
As for transformers.............
I would put it in the step-down mode, and pick up some more CMR. You can change one resistor on the Hypex module to pick up the gain that you lose.
Roger:
Are the Auricap guys any way associated with what was SiderealKaps? They look a lot alike......same epoxy.......typeface........both are from around San Diego............etc.
Jocko
I would put it in the step-down mode, and pick up some more CMR. You can change one resistor on the Hypex module to pick up the gain that you lose.
Roger:
Are the Auricap guys any way associated with what was SiderealKaps? They look a lot alike......same epoxy.......typeface........both are from around San Diego............etc.
Jocko
Questions answered
Jocko,
Read your mail!
JJ2
Rather than give up the good bass qualities of the 2.2uf input cap try direct coupling the input to your preamps cathode followers. This will improve the phase margin and improve stability maybe even enough for it to work. You can try it with just jumpering out the caps and no other changes. I did offer to help you with this but required your name so I would know who I was helping. The offer still stands.
Roger
Jocko,
Read your mail!
JJ2
Rather than give up the good bass qualities of the 2.2uf input cap try direct coupling the input to your preamps cathode followers. This will improve the phase margin and improve stability maybe even enough for it to work. You can try it with just jumpering out the caps and no other changes. I did offer to help you with this but required your name so I would know who I was helping. The offer still stands.
Roger
Well theres a lot of stuff for me to try when I order the UCD's🙂
Roger, do you know if theres any company's that can supply 2.2uf Auricaps in the UK? the only place I can find is WAD http://www.worldaudiodesign.com/catalog/ but they seem to be alot more expensive than from Michael Percy
Apart from OPA627,AD8620,NE5532 has anybody else tried other op-amps in the UCD's?
How about AD8066,OPA2132 or AD826
Roger, do you know if theres any company's that can supply 2.2uf Auricaps in the UK? the only place I can find is WAD http://www.worldaudiodesign.com/catalog/ but they seem to be alot more expensive than from Michael Percy
Apart from OPA627,AD8620,NE5532 has anybody else tried other op-amps in the UCD's?
How about AD8066,OPA2132 or AD826
Cap question
For now the best you can do is order directly from Audience. Most items are in stock, in quantity and the shipping won't be much as the package will be light. They are working to get a dealer over there but don't have one yet.
www.audience-av.com
Roger
For now the best you can do is order directly from Audience. Most items are in stock, in quantity and the shipping won't be much as the package will be light. They are working to get a dealer over there but don't have one yet.
www.audience-av.com
Roger
t. said:
i use AD826 in my ucd180 with excellent result
(the ad826 has its own unregulated PSU )
alain
Thanks Roger🙂
I'm tempted to get the 450v ones instead of the 200v, I can then try them in higher voltage devices too.
Do the 450v sound the same as the 200v ones if tried in lower voltage coupling applications or would it be best to stick with the 200v?
Alain,
Did you compare the AD826 against the AD8620?
Cheers Guys!
I'm tempted to get the 450v ones instead of the 200v, I can then try them in higher voltage devices too.
Do the 450v sound the same as the 200v ones if tried in lower voltage coupling applications or would it be best to stick with the 200v?
Alain,
Did you compare the AD826 against the AD8620?
Cheers Guys!
Cap expert?
I am not quite sure how I became the cap expert/authority all of a sudden but will throw in my 2 cents worth anyway. In a general way the higher voltage caps do sound a little better. In most cases this slight difference is not worth the higher price and additional difficulties with mounting a larger cap. In this particular application there is the additional surface area to pick up noise to be considered as well. As a general rule, in preamps and amps, it is best to go no higher in voltage than you really need. In speakers you may not have a choice as the larger values needed may not be available in the higher voltages. If they are you have to consider the extra volume effects may be significant on cabinet tuning.
Auricaps may be the least microphonic caps going but you still don’t want them flopping around so plan your installation with how you will hold them in place. This is also important to remove stress from the leads and prevent lifted pads from the circuit board. Follow the recommended procedure for outside foil connection. In some applications this can make a large difference like in tube coupling it is very important.
Further information is available here; (Soon to be updated!)
http://www.audience-av.com/auricap_application_notes.htm
Roger
I am not quite sure how I became the cap expert/authority all of a sudden but will throw in my 2 cents worth anyway. In a general way the higher voltage caps do sound a little better. In most cases this slight difference is not worth the higher price and additional difficulties with mounting a larger cap. In this particular application there is the additional surface area to pick up noise to be considered as well. As a general rule, in preamps and amps, it is best to go no higher in voltage than you really need. In speakers you may not have a choice as the larger values needed may not be available in the higher voltages. If they are you have to consider the extra volume effects may be significant on cabinet tuning.
Auricaps may be the least microphonic caps going but you still don’t want them flopping around so plan your installation with how you will hold them in place. This is also important to remove stress from the leads and prevent lifted pads from the circuit board. Follow the recommended procedure for outside foil connection. In some applications this can make a large difference like in tube coupling it is very important.
Further information is available here; (Soon to be updated!)
http://www.audience-av.com/auricap_application_notes.htm
Roger
I am not quite sure how I became the cap expert/authority all of a sudden
Pretty much the same way that I became the wire and cable "expert" in the lab I used to work in. You show interest in something that no one else seems to be interested in....................
Jocko
Pretty much the same way that I became the wire and cable "expert" in the lab I used to work in. You show interest in something that no one else seems to be interested in....................
Jocko
Jocko,
I know what you mean 😀
Unfortunatly, your theory is not true for women. Everyone's interested. None of us are experts!
OK, back to topic
I know what you mean 😀
Unfortunatly, your theory is not true for women. Everyone's interested. None of us are experts!
OK, back to topic
Expert?
All to true! Some people gain a little knowledge and a few buzz words and are instant experts. Even though I do have some obscure knowledge available I do not consider myself an expert! Many years ago when I worked on the factory floor on very large computers I did consider myself an expert. By this I use the definition that no one else in the whole world had as complete an understanding of this particular product. This can happen only if you work with/on one thing day after day. I don’t see much of that kind of thing happening anymore. As soon as you learn a product it is replaced with a new more complex model. These new products are so complex that even the engineers only know a small part of it. The service guys probably have the best overall knowledge and it isn’t very extensive.
Bottom line is there are less real experts than ever before! (Of course I am referring to our particular niche here.)
Roger
Yes, back to topic.
All to true! Some people gain a little knowledge and a few buzz words and are instant experts. Even though I do have some obscure knowledge available I do not consider myself an expert! Many years ago when I worked on the factory floor on very large computers I did consider myself an expert. By this I use the definition that no one else in the whole world had as complete an understanding of this particular product. This can happen only if you work with/on one thing day after day. I don’t see much of that kind of thing happening anymore. As soon as you learn a product it is replaced with a new more complex model. These new products are so complex that even the engineers only know a small part of it. The service guys probably have the best overall knowledge and it isn’t very extensive.
Bottom line is there are less real experts than ever before! (Of course I am referring to our particular niche here.)
Roger
Yes, back to topic.
Bit off-topic again..
I finally get BHC T-Network 4-pole caps to my UCD180 ps.
Caps are made week 51/-98. Even if shelf life is over 10 years in BHC specs, i think maybe it is better to make "re-ageing" procedure before i take caps to use.
I get following answer from BHC:
"
Your assumption for the date code is correct.
Long storage affects principally the leakage current which increases due to deterioration of the aluminium oxide dielectric. This is reversible by following the re-ageing procedure which is essentially applying rated DC voltage for 1 hour. The charging current should be limited to the either twice the specified leakage current limit or 5mA whichever is the greater.
After a period of 12 hours, the leakage current should be measured to ensure it is still within the specification limit.
"
Can you kindly tell how this prosedure should be done in practice.
Do i need lab power supply with current limiting ?
-Pasi
I finally get BHC T-Network 4-pole caps to my UCD180 ps.
Caps are made week 51/-98. Even if shelf life is over 10 years in BHC specs, i think maybe it is better to make "re-ageing" procedure before i take caps to use.
I get following answer from BHC:
"
Your assumption for the date code is correct.
Long storage affects principally the leakage current which increases due to deterioration of the aluminium oxide dielectric. This is reversible by following the re-ageing procedure which is essentially applying rated DC voltage for 1 hour. The charging current should be limited to the either twice the specified leakage current limit or 5mA whichever is the greater.
After a period of 12 hours, the leakage current should be measured to ensure it is still within the specification limit.
"
Can you kindly tell how this prosedure should be done in practice.
Do i need lab power supply with current limiting ?
-Pasi
Hi,
I think you mean the "DE-aging" procedure, commonly known as "re-forming" the capacitor.
If BC shelf life is ten years (most I've seen are given at five) I think you can rely on that and not bother with trying to reform them. Typically shelf life is given at an ambient temperature MUCH higher than typical 25 dec C ambient, which means their rated shelf life is much much less than it is actually likely to be.
I just took a set of caps that I suspected were bad to begin with out of a burnt amplifier that has sat in parts in a box for at least two years, caps had a good five years of use on them.
They powered right up and worked fine, I had considered reforming them but took the chance it wouldn't need it.
It has nothing to do with sonic performance or anything just it's a question of maintaning their DC voltage rating.
Anyway, please check the ambient temp that the shelf life was given at and go from there.
If you decide you must reform you don't need a lab supply but it makes life alot easier, because it must be reformed at preferably the exact same voltage it will see when in use (or just slightly higher, and they'll "de-form" while in use to the working voltage. Never apply more than the rated voltage.
You absolutely must limit the current through the cap while doing this, assuming it no longer has the ability to block DC voltage at all, too much current will raise the voltage too quickly, boil the electrolytic building explosive pressure inside the cap. If you're not using a lab supply then use a series resistor. Don't get smart and try to use a lightbulb here.... the inrush will defeat the purpose and possibly cause damage if they in fact do need reforming.
I've read of some who bring up the voltage very slowly, over a period of a day or so. It seems acceptable to apply the given voltage (heavily current limited) right away.
The best solution overall will always be to follow what the cap manufacturer recommends for them.
Yeah it's a real pain to do if you dont' have a rather high voltage lab supply to use, but if you can use some "stand in" caps, or maybe whatever you used before you got your T-networks, do your ohms law math to get the right value of series resistors that will set the current into the caps accordingly, it will re-form at the perfect voltage providing they're the same capacitance, and with minimal effort.
I think my T-networks are from 98 as well and I dont' intend on re-forming them.
Regards,
Chris
I think you mean the "DE-aging" procedure, commonly known as "re-forming" the capacitor.
If BC shelf life is ten years (most I've seen are given at five) I think you can rely on that and not bother with trying to reform them. Typically shelf life is given at an ambient temperature MUCH higher than typical 25 dec C ambient, which means their rated shelf life is much much less than it is actually likely to be.
I just took a set of caps that I suspected were bad to begin with out of a burnt amplifier that has sat in parts in a box for at least two years, caps had a good five years of use on them.
They powered right up and worked fine, I had considered reforming them but took the chance it wouldn't need it.
It has nothing to do with sonic performance or anything just it's a question of maintaning their DC voltage rating.
Anyway, please check the ambient temp that the shelf life was given at and go from there.
If you decide you must reform you don't need a lab supply but it makes life alot easier, because it must be reformed at preferably the exact same voltage it will see when in use (or just slightly higher, and they'll "de-form" while in use to the working voltage. Never apply more than the rated voltage.
You absolutely must limit the current through the cap while doing this, assuming it no longer has the ability to block DC voltage at all, too much current will raise the voltage too quickly, boil the electrolytic building explosive pressure inside the cap. If you're not using a lab supply then use a series resistor. Don't get smart and try to use a lightbulb here.... the inrush will defeat the purpose and possibly cause damage if they in fact do need reforming.
I've read of some who bring up the voltage very slowly, over a period of a day or so. It seems acceptable to apply the given voltage (heavily current limited) right away.
The best solution overall will always be to follow what the cap manufacturer recommends for them.
Yeah it's a real pain to do if you dont' have a rather high voltage lab supply to use, but if you can use some "stand in" caps, or maybe whatever you used before you got your T-networks, do your ohms law math to get the right value of series resistors that will set the current into the caps accordingly, it will re-form at the perfect voltage providing they're the same capacitance, and with minimal effort.
I think my T-networks are from 98 as well and I dont' intend on re-forming them.
Regards,
Chris
Thank you Chris.
Sounds quite difficult procedure to me. Maybe i forget it..
This is BHC specs of shelf life:
http://www.bhc.co.uk/electric04.htm#shelflife
How you like T-caps sound?
I have now Rifa PEH200:s with UCD and hope to get improvement with T:s.
Sounds quite difficult procedure to me. Maybe i forget it..
This is BHC specs of shelf life:
http://www.bhc.co.uk/electric04.htm#shelflife
How you like T-caps sound?
I have now Rifa PEH200:s with UCD and hope to get improvement with T:s.
Hi Pasi,
My pleasure.
I see where you got the "Re-aging" term from, I can't believe they called it that! I'm willing to bet if you researched capacitor re-aging on google all you're going to find is BHC info.
If you want bit more than that to read on the topic try searching for re forming.
I see from their shelf life graph that their "10 year" rating is in fact at room temperature. That's probably to try and make it look better than other capacitors, which is usually given at at least twice room temperature, and ends up being around 5 years, but they look the same to me, buyer beware and all... nice marketing trick there.
Notice that it say's in "In region 2 the leakage current may initially exceed the specified limit and if the measured value is higher than twice the specified limit then re-ageing is recommended. "
Region 2 is only seen after about 11 years storage at a temp of 25 degrees C.
Once put in use it should reform at the given voltage and leakage should improve after initial use. If it doesn't, it will explode, and you know you made a mistake by not doing it.
Your questioning this was excellent work/research on your part, very nicely done.
I'll leave the final educated decision of weither or not you should in fact reform up to you, but again, I won't be reforming mine.
I haven't had the chance to try mine out yet, I have a set of Elna Cerafines to compare them with, they'll likely be going in first, then the T-networks, then both together, unless I decide one is very much inferior..
So I'm sure you'll get to try them out first, please report back with your impressions of them, and very best of luck with your build.
BTW Roger, our resident cap expert 🙂 What's your prediction on how a cap of the same value will sound given it's half the size to a "comparable" one? I know they aren't comparable..
I think it should be interesting anyway.
Regards,
Chris
PS:
Don't let the complication scare you away from doing it if you think it needs to be done, or if doing it would make you feel better?
If you're Rifa caps are of the same capacitance, then
45 / .005 = 9 000 (I assume each rail wont' go higher than 45V worst case...
Just use a standard 1/4 watt 10K ohm resistor in series with each rail in the live line of the input pair of the T networks. Leave it on a few hours or overnight and you're done!
45/10K= 4.5mA current to each cap, probably worst case,
and they'll have a drop over them of 45 volts, so power dissipated is V*I,=45*0.0045=0.20 watts. They're within spec, you should be able to sleep 🙂
My pleasure.
I see where you got the "Re-aging" term from, I can't believe they called it that! I'm willing to bet if you researched capacitor re-aging on google all you're going to find is BHC info.
If you want bit more than that to read on the topic try searching for re forming.
I see from their shelf life graph that their "10 year" rating is in fact at room temperature. That's probably to try and make it look better than other capacitors, which is usually given at at least twice room temperature, and ends up being around 5 years, but they look the same to me, buyer beware and all... nice marketing trick there.
Notice that it say's in "In region 2 the leakage current may initially exceed the specified limit and if the measured value is higher than twice the specified limit then re-ageing is recommended. "
Region 2 is only seen after about 11 years storage at a temp of 25 degrees C.
Once put in use it should reform at the given voltage and leakage should improve after initial use. If it doesn't, it will explode, and you know you made a mistake by not doing it.
Your questioning this was excellent work/research on your part, very nicely done.
I'll leave the final educated decision of weither or not you should in fact reform up to you, but again, I won't be reforming mine.
I haven't had the chance to try mine out yet, I have a set of Elna Cerafines to compare them with, they'll likely be going in first, then the T-networks, then both together, unless I decide one is very much inferior..
So I'm sure you'll get to try them out first, please report back with your impressions of them, and very best of luck with your build.
BTW Roger, our resident cap expert 🙂 What's your prediction on how a cap of the same value will sound given it's half the size to a "comparable" one? I know they aren't comparable..
I think it should be interesting anyway.
Regards,
Chris
PS:
Don't let the complication scare you away from doing it if you think it needs to be done, or if doing it would make you feel better?
If you're Rifa caps are of the same capacitance, then
45 / .005 = 9 000 (I assume each rail wont' go higher than 45V worst case...
Just use a standard 1/4 watt 10K ohm resistor in series with each rail in the live line of the input pair of the T networks. Leave it on a few hours or overnight and you're done!
45/10K= 4.5mA current to each cap, probably worst case,
and they'll have a drop over them of 45 volts, so power dissipated is V*I,=45*0.0045=0.20 watts. They're within spec, you should be able to sleep 🙂
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