It's a single "8 leg opamp".
I think one will need something like this to replace stock dual opamp:
http://www.soundlabsgroup.com.au/browndog/browndog_dualso8dip8_so8.htm
Plus two OPA627 smd wich are not so expensive on ebay. Am I wrong?
I think my local cellphone technician can solder these
Regards
Mauricio
I think one will need something like this to replace stock dual opamp:
http://www.soundlabsgroup.com.au/browndog/browndog_dualso8dip8_so8.htm
Plus two OPA627 smd wich are not so expensive on ebay. Am I wrong?
I think my local cellphone technician can solder these
Regards
Mauricio
I'm thinking about ordering a pair of UCD400 modules in a few weeks.
I'd like to order the ones with the standard op-amps to try out and replace these with AD8620 which I have spare just to see how they compare.
Hows the voltage set for these op-amps, is it done by zeners or regulators?
Is there any component changes that would need to be done?
It seems the UCD modules are popular judging by the amount of posts
Cheers!
I'd like to order the ones with the standard op-amps to try out and replace these with AD8620 which I have spare just to see how they compare.
Hows the voltage set for these op-amps, is it done by zeners or regulators?
Is there any component changes that would need to be done?
It seems the UCD modules are popular judging by the amount of posts
Cheers!
Zener values
T,
The UcD400 AD modules use 12v rated SM zeners. They are marked D17, D18. The standard modules have exactly the same designator on their part as well. It is marked ZF, what ever that means. This might be a brand ID and have nothing to do with the value. I do know some modules were made with 15v parts and this would be too much for the 8620's.
Jan-Peter would be the one to give you a better answer.
Of course you can always fire them up and measure it directly. If you do, use heat shrink and insulate all but the very tips of your probes. The test points are so close together it would be real easy to slip and blow the whole thing!
Roger
T,
The UcD400 AD modules use 12v rated SM zeners. They are marked D17, D18. The standard modules have exactly the same designator on their part as well. It is marked ZF, what ever that means. This might be a brand ID and have nothing to do with the value. I do know some modules were made with 15v parts and this would be too much for the 8620's.
Jan-Peter would be the one to give you a better answer.
Of course you can always fire them up and measure it directly. If you do, use heat shrink and insulate all but the very tips of your probes. The test points are so close together it would be real easy to slip and blow the whole thing!
Roger
Thanks guys
I have a few different types of smd op-amps so I thought if I buy the ones with the standard op-amps fitted at least I can try some different types first which would be suitable and have a low dc offset.
Obviously some types require a lower voltage than +/-15v so I thought i'd ask first just to make sure
If they used voltage regs I would have liked to have removed them and used my spare ALW super regs instead
If I get a pair of these built up I'll need to get the best I can out of them, no doubt my friends will like to do a shootout against their amps
I have a few different types of smd op-amps so I thought if I buy the ones with the standard op-amps fitted at least I can try some different types first which would be suitable and have a low dc offset.
Obviously some types require a lower voltage than +/-15v so I thought i'd ask first just to make sure
If they used voltage regs I would have liked to have removed them and used my spare ALW super regs instead
If I get a pair of these built up I'll need to get the best I can out of them, no doubt my friends will like to do a shootout against their amps
I've just built a softstart for my transformer I'd like to use with the UCD400 if its suitable
It has 2 x 40-0-40 secondary's and is rated at 2780va this was removed from a 2000watt poweramp so it should run the modules ok
I have a pair of these Avondalecap-6 modules to use for the rectification and smoothing caps
The diodes are MBR20200 Schottkies with 3 x 6800uf 80v caps per rail so theres a total of 12 x 6800uf capacitors for a stereo amp.
Would it be worth changing the 12 x 6800uf to 12 x 10,000uf instead?
Maybe a bit overkill but the transformer is huge
It has 2 x 40-0-40 secondary's and is rated at 2780va
this was removed from a 2000watt poweramp so it should run the modules okI have a pair of these Avondalecap-6 modules to use for the rectification and smoothing caps
The diodes are MBR20200 Schottkies with 3 x 6800uf 80v caps per rail so theres a total of 12 x 6800uf capacitors for a stereo amp.
Would it be worth changing the 12 x 6800uf to 12 x 10,000uf instead?
Maybe a bit overkill but the transformer is huge
Attachments
replacement for the bootstrap cap ETC.
Hi all,
I have a number of questions here. Maybe, should have put them in the hotrod section.
Wasn't sure, what is the value of the bootstrap cap, what code on the board, and can it be substituted with a tenth of the value by using a film thype cap? Thanks. I think someone said it was C22.
Was thinking about just also replacing the imput caps with Auricaps. Would they fit on the board? 2.2 UF 50V
That output cap, .068 what is the schematic number for it?
You know, Bruno and Jan-Peter, you guys might consider on that module, just replacing these four caps with Auricaps; or at least something better than standard electrolytics. If I want these upgrades done, I am gonna have to pay to have these mods/upgrades done anyway, so why not have them done at the factory and pay a little less. I am a totally blind person. I can solder, but have not developed enough skill to do PCB work. So for us wannabees, we have to make due. Maybe, have that as an option. Replacing the 2 imput caps, the 1 output cap, and maybe the bootstrap cap. That would pretty much cover the bases. I do realize you were trying to keep the price down.
Ray Bronk
Hi all,
I have a number of questions here. Maybe, should have put them in the hotrod section.
Wasn't sure, what is the value of the bootstrap cap, what code on the board, and can it be substituted with a tenth of the value by using a film thype cap? Thanks. I think someone said it was C22.
Was thinking about just also replacing the imput caps with Auricaps. Would they fit on the board? 2.2 UF 50V
That output cap, .068 what is the schematic number for it?
You know, Bruno and Jan-Peter, you guys might consider on that module, just replacing these four caps with Auricaps; or at least something better than standard electrolytics. If I want these upgrades done, I am gonna have to pay to have these mods/upgrades done anyway, so why not have them done at the factory and pay a little less. I am a totally blind person. I can solder, but have not developed enough skill to do PCB work. So for us wannabees, we have to make due. Maybe, have that as an option. Replacing the 2 imput caps, the 1 output cap, and maybe the bootstrap cap. That would pretty much cover the bases. I do realize you were trying to keep the price down.
Ray Bronk
Hi Ray,
They're trying to keep cost down and also not cater to any particular niche.
For instance I'd much rather spend money on doing what it takes so that I can DC couple a balanced signal as opposed to spending money on an ever inferior capacitor.
In the meantime they've previously stated reasons for not being able to sell a fully "optimized" module to the DIY community.
Bootstrap caps are 220uF and you shouldn't go smaller, it was sized that way for minimal gate sag under heavy clipping conditions.
You probably stand more to lose than you could possibly gain by replacing it with a film cap of 1/10 the value.
The .68uF output filter caps are easy to spot, the square one on the top of the board placed next to the filter coil.
BTW have you seen the hotrod thread?
If you don't like being a wannabe cross over to a DIYer, hone your solder skills on a scrap computer board or something. I'm going to.
Or yeah you can pay to have it done, but I don't want to pay for your mods.
Regards,
Chris
They're trying to keep cost down and also not cater to any particular niche.
For instance I'd much rather spend money on doing what it takes so that I can DC couple a balanced signal as opposed to spending money on an ever inferior capacitor.
In the meantime they've previously stated reasons for not being able to sell a fully "optimized" module to the DIY community.
Bootstrap caps are 220uF and you shouldn't go smaller, it was sized that way for minimal gate sag under heavy clipping conditions.
You probably stand more to lose than you could possibly gain by replacing it with a film cap of 1/10 the value.
The .68uF output filter caps are easy to spot, the square one on the top of the board placed next to the filter coil.
BTW have you seen the hotrod thread?
If you don't like being a wannabe cross over to a DIYer, hone your solder skills on a scrap computer board or something. I'm going to.
Or yeah you can pay to have it done, but I don't want to pay for your mods.
Regards,
Chris
Someone who knows how to hear!
Ray,
You must have an interesting computer setup, will have to tell us about it sometime.
The 2.2uf Auricaps are way too large to go on the circuit board. The usual way to implement them is to remove and jumper out the on board 22uf electrolytics. Then put the Auricaps between the input connector on the UcD and the RCA input jacks. Have a 1 meg ohm resistors added across the input jacks to discharge any static electricity that might accumulate there.
The bootstrap cap needs a certain minimum value of capacitance and no film cap that would fit would be enough. I would consider the 22uf installed as the minimum. A better quality and larger value cap might lower noise a tiny bit but for me the reason to replace it has more to do with improving reliability than anything else. So use a good quality 105 deg rated 25v cap like the Panasonic FC series. The 220 uf cap will fit, I have been told. I personally used Nichicons equivalent and it fit fine.
The .68 uf output filter cap is a whole other story. I used the larger wire lead types on my first amp with good results. This was the .68 @ 450v Auricap. I know I have worsened the EMI spec considerably but with the amp in a totally enclosed aluminum box this is no problem for this particular aplication. I don’t know if the added inductance is hurting anything else, it sure sounds good. All this was the reason I designed a new cap that Audience will be building for me. This new cap will have all the good Auricap quality’s as well as being PC mount and being a direct solder in replacement for the one on the board. It will be some time till they are available, I haven’t even received the engineering samples for approval yet.
Roger
Ray,
You must have an interesting computer setup, will have to tell us about it sometime.
The 2.2uf Auricaps are way too large to go on the circuit board. The usual way to implement them is to remove and jumper out the on board 22uf electrolytics. Then put the Auricaps between the input connector on the UcD and the RCA input jacks. Have a 1 meg ohm resistors added across the input jacks to discharge any static electricity that might accumulate there.
The bootstrap cap needs a certain minimum value of capacitance and no film cap that would fit would be enough. I would consider the 22uf installed as the minimum. A better quality and larger value cap might lower noise a tiny bit but for me the reason to replace it has more to do with improving reliability than anything else. So use a good quality 105 deg rated 25v cap like the Panasonic FC series. The 220 uf cap will fit, I have been told. I personally used Nichicons equivalent and it fit fine.
The .68 uf output filter cap is a whole other story. I used the larger wire lead types on my first amp with good results. This was the .68 @ 450v Auricap. I know I have worsened the EMI spec considerably but with the amp in a totally enclosed aluminum box this is no problem for this particular aplication. I don’t know if the added inductance is hurting anything else, it sure sounds good. All this was the reason I designed a new cap that Audience will be building for me. This new cap will have all the good Auricap quality’s as well as being PC mount and being a direct solder in replacement for the one on the board. It will be some time till they are available, I haven’t even received the engineering samples for approval yet.
Roger
Hi,
Stock bootstrap cap is an 85 degree C 220uF 16V cap.
I think they were once 100uF .... if it's more than doubled I'm sure there's a good reason why.
I think I fully agree with your reason for upgrading it. Reliability or just longer life exptectancy.
Why go more than 16 volts, it's essentially regulated, and 16 leaves a nice margin on a regulated cap right?
Regards,
Chris
Stock bootstrap cap is an 85 degree C 220uF 16V cap.
I think they were once 100uF .... if it's more than doubled I'm sure there's a good reason why.
I think I fully agree with your reason for upgrading it. Reliability or just longer life exptectancy.
Why go more than 16 volts, it's essentially regulated, and 16 leaves a nice margin on a regulated cap right?
Regards,
Chris
A couple of points
Chris,
I mostly agree with you which I will get to. I am not sure of the 220uf original bootstrap value. I have already changed them out on all the modules I have here. If that is the case I to would consider the 220uf as a minimum acceptable value.
Yes, no cap is the best of all when conditions warrant. However, as the single part that protects the modules and your speakers from a DC disaster they are cheap insurance. The Auricap is very benign and does not add coloration to the amp. This is a very small negative including cost and to me is worth it to not have to worry about some preamp taking out everything. The UcD’s DC protection assumes that the DC is of small value and this may not be the case.
I have no problem living with DC coupling in my own checked out setups but sure wouldn’t feel right sending a unit out in public that way, not having a clue as to what harebrained thing it will be connected to. In my designs I also include input circuit rail diode protection so if a very large signal is applied, like ½ the AC line when someone unplugs the cables with out turning things off, it don’t go up in smoke. Worst case is it will take out a small input resistor.
Roger
Didn’t see your second post till this one was also posted. I am sure 16v is enough especially with a 105deg part. I used 25 volt ones as they were what I had and would fit.
If I order any I will go to 470uf @ 16v 105deg in the same case size.
Chris,
I mostly agree with you which I will get to. I am not sure of the 220uf original bootstrap value. I have already changed them out on all the modules I have here. If that is the case I to would consider the 220uf as a minimum acceptable value.
Yes, no cap is the best of all when conditions warrant. However, as the single part that protects the modules and your speakers from a DC disaster they are cheap insurance. The Auricap is very benign and does not add coloration to the amp. This is a very small negative including cost and to me is worth it to not have to worry about some preamp taking out everything. The UcD’s DC protection assumes that the DC is of small value and this may not be the case.
I have no problem living with DC coupling in my own checked out setups but sure wouldn’t feel right sending a unit out in public that way, not having a clue as to what harebrained thing it will be connected to. In my designs I also include input circuit rail diode protection so if a very large signal is applied, like ½ the AC line when someone unplugs the cables with out turning things off, it don’t go up in smoke. Worst case is it will take out a small input resistor.
Roger
Didn’t see your second post till this one was also posted. I am sure 16v is enough especially with a 105deg part. I used 25 volt ones as they were what I had and would fit.
If I order any I will go to 470uf @ 16v 105deg in the same case size.
Hi Roger,
The forum moves pretty quick around here doesn't it?
Jan-Peter said in the hotrod thread the bootstrap caps are all 220uF. I remember because I was surprised thinking they were still 100uF which some people used to consider too big too.
I've checked my UCD180 modules for the information given previously, still stock and innocent.
I agree when building something that's getting plugged into who knows what by who knows who, you have to take the all encompassing approach.
It's not everyone here doing that though, I wasn't knocking your caps Roger, just think it's best kept as a mod myself.
In fact I hope they work out very well and look forward to getting to try a few of your filter caps someday.
Regards,
Chris
The forum moves pretty quick around here doesn't it?
Jan-Peter said in the hotrod thread the bootstrap caps are all 220uF. I remember because I was surprised thinking they were still 100uF which some people used to consider too big too.
I've checked my UCD180 modules for the information given previously, still stock and innocent.
I agree when building something that's getting plugged into who knows what by who knows who, you have to take the all encompassing approach.
It's not everyone here doing that though, I wasn't knocking your caps Roger, just think it's best kept as a mod myself.
In fact I hope they work out very well and look forward to getting to try a few of your filter caps someday.
Regards,
Chris
Bootstrap capacitor;
In the present modules we used 100uF. The reason for increasing the value to 220uF is that when the amp clips very heavy (30% distortion) and at a very low signal, 10Hz. You don't have enough energy in the caps to drive the top power fet.
By normal use the amp will work without any problem even when you reduce the cap to 100uF.
This capacitor, as far as we know, has no influence on the sonic performance of the amplifier.
Jan-Peter
In the present modules we used 100uF. The reason for increasing the value to 220uF is that when the amp clips very heavy (30% distortion) and at a very low signal, 10Hz. You don't have enough energy in the caps to drive the top power fet.
By normal use the amp will work without any problem even when you reduce the cap to 100uF.
This capacitor, as far as we know, has no influence on the sonic performance of the amplifier.
Jan-Peter
