Can anyone help me source replacement filter caps for a Hafler?
They need to be the "low post" variety 2" X 4" and a max height of 4.25" with the screws in place.
Somewhere around 15K uF computer grade 75WVDC would be good.
I've been out of the loop for 2 years and lost links to caps so your help would be appreciated. I tried Mouser but could only find what looked to be the high post caps.
They need to be the "low post" variety 2" X 4" and a max height of 4.25" with the screws in place.
Somewhere around 15K uF computer grade 75WVDC would be good.
I've been out of the loop for 2 years and lost links to caps so your help would be appreciated. I tried Mouser but could only find what looked to be the high post caps.
Dick:
I recently upgraded my Hafler 220's with 'modern' power supply cap. Try going to www.apexjr.com and if you don't see what you need, call Steve and ask him. Also go to our favorite auction house and search on 'capacitor computer' and it will usually turn up a lead or two. Good luck.
Chuck
I recently upgraded my Hafler 220's with 'modern' power supply cap. Try going to www.apexjr.com and if you don't see what you need, call Steve and ask him. Also go to our favorite auction house and search on 'capacitor computer' and it will usually turn up a lead or two. Good luck.
Chuck
I think there are caps at Mouser that are low post. I just can't seem to figure out how to search their web site. Very cumbersome and it seems keyed mostly to part number, which of course I don't have.
I will check Apex to see if he has low post screw terminal filter caps. Most of the stuff I recall seeing at his site were of the snap in variety.
Musical concepts caps work wonders but SOooo pricey!
One thing that sounds almost as good is to add a 1000 uF electrolytic in parallel to the 10K caps. But, not very elegant and not for everybody:
I will check Apex to see if he has low post screw terminal filter caps. Most of the stuff I recall seeing at his site were of the snap in variety.
Musical concepts caps work wonders but SOooo pricey!
One thing that sounds almost as good is to add a 1000 uF electrolytic in parallel to the 10K caps. But, not very elegant and not for everybody:
Attachments
Dick West said:
They don't send you their paper catalog? I find that for both Mouser and DK the search engines can lead you away from what you are looking for. With both companies the service is excellent -- the folks are really friendly as well. I almost always select US Postal Priority and the package will get here the next day.
Hi Dick,
I have a recent Mouser catalog, and found the following rough matches to what you need:
Mouser Part Number Brand uF WVDC Diameter Height Price
539-CGS123U075V4C Mallory 12000 75 2.0 4.125 $25.49
539-CGS153U075V5L Mallory 15000 75 2.0 5.625 $27.78
75-36DY183F075BC2A Vishay/Sprague 18000 75 2.0 4.125 $36.02
75-36DX173G075CC2A Vishay/Sprague 17000 75 2.5 4.125 $36.85
598-DCMC100V203 Cornell Dubilier 20000 100 2.0 4.125 $54.81
The only 15K uF I found is too tall.
Copy the above text into Notepad or something to see it better.
I have a recent Mouser catalog, and found the following rough matches to what you need:
Mouser Part Number Brand uF WVDC Diameter Height Price
539-CGS123U075V4C Mallory 12000 75 2.0 4.125 $25.49
539-CGS153U075V5L Mallory 15000 75 2.0 5.625 $27.78
75-36DY183F075BC2A Vishay/Sprague 18000 75 2.0 4.125 $36.02
75-36DX173G075CC2A Vishay/Sprague 17000 75 2.5 4.125 $36.85
598-DCMC100V203 Cornell Dubilier 20000 100 2.0 4.125 $54.81
The only 15K uF I found is too tall.
Copy the above text into Notepad or something to see it better.
Poles in the amp
djk,
As I recall you posted once 2-3 years ago about the DH-200's poles in the circuit design and implied that changing some components was not always a good idea.
I have a pair of DH-200 mono blocks (single channel mono aural) that sound to my ears just great, what with a separate power supply for each channel. Plus, each channel has about 80k uF of capacitance. Needless to say I start these mono aural amps with a soft start circuit.
Now, what would happen if I added a 3rd n-channel and 3rd p-channel MOSFET to each mono aural amp? My heat sink is already drilled for a 3rd MOSFET and I have the extra MOSFETs and also have an original Hafler MOSFET checker for matching them.
Would the DH-200 circuit complain if it drove 6 MOSFETs per channel instead of 4?
djk,
As I recall you posted once 2-3 years ago about the DH-200's poles in the circuit design and implied that changing some components was not always a good idea.
I have a pair of DH-200 mono blocks (single channel mono aural) that sound to my ears just great, what with a separate power supply for each channel. Plus, each channel has about 80k uF of capacitance. Needless to say I start these mono aural amps with a soft start circuit.
Now, what would happen if I added a 3rd n-channel and 3rd p-channel MOSFET to each mono aural amp? My heat sink is already drilled for a 3rd MOSFET and I have the extra MOSFETs and also have an original Hafler MOSFET checker for matching them.
Would the DH-200 circuit complain if it drove 6 MOSFETs per channel instead of 4?
Dick W, you just gave me an idea on what to do with that chassis/transformer you sent me... 
Remember i have those two Hafler P-230's... I could take one channel off of each one and make a pair of monoblocks out of the two amps. I could then take the two leftover channels and use them on the chassis you gave me.
Ever since i picked up an Ashly FET-200 the extra P230 has just been sitting so this seems like a worthwhile effort. I would have to machine side panels for the two monoblocks, but that won't be difficult.
I can't believe i didn't think to do this before....
Remember i have those two Hafler P-230's... I could take one channel off of each one and make a pair of monoblocks out of the two amps. I could then take the two leftover channels and use them on the chassis you gave me.
Ever since i picked up an Ashly FET-200 the extra P230 has just been sitting so this seems like a worthwhile effort. I would have to machine side panels for the two monoblocks, but that won't be difficult.
I can't believe i didn't think to do this before....
AJ,
The first things you will notice about putting each channel in its separate chassis and with its separate power supply is an increase in the size of the sound stage. It will be wider and with more depth and resolution of small detail. Without cross modulation between channels each can more accurately reproduce the signal. Dual mono power supplies is absolutely worth the effort and cost, especially if you have the hardware handy to do so.
For my mono blocks I moved each transformer over to the right side to better balance the weight and keep all AC as far away as possible from the signal bearing components. Then, as you can see, there is more room for larger caps.
In the picture attached you can see the pair of blue 40K uF caps. The yellow device is a 120VAC time delay relay that allows for a time delay start. Without it the 80k uF in the PS would fry some fuses, diode bridge, etc.
An end cap can be made easily from a piece of something like galvaneel (sp) available from a sheet metal shop and they will cut it to size. If you lay out the plans for it you can have the shop include a right angle blend in front to attach a face plate. On my end caps I mounted a nice handle to assist in moving the mono amps.
When I get some shorter caps I will mount them and then be able to put the lids on the amps. In the meantime please note I have no cats or toddlers with little fingers so the open chassis is not too dangerous.
The picture is from 4 years ago when I had a pair of DH-220 circuit cards mounted-- and the sound was really great. Currently I have a pair of DH-200 cards mounted and the sound, again, is really great!
The first things you will notice about putting each channel in its separate chassis and with its separate power supply is an increase in the size of the sound stage. It will be wider and with more depth and resolution of small detail. Without cross modulation between channels each can more accurately reproduce the signal. Dual mono power supplies is absolutely worth the effort and cost, especially if you have the hardware handy to do so.
For my mono blocks I moved each transformer over to the right side to better balance the weight and keep all AC as far away as possible from the signal bearing components. Then, as you can see, there is more room for larger caps.
In the picture attached you can see the pair of blue 40K uF caps. The yellow device is a 120VAC time delay relay that allows for a time delay start. Without it the 80k uF in the PS would fry some fuses, diode bridge, etc.
An end cap can be made easily from a piece of something like galvaneel (sp) available from a sheet metal shop and they will cut it to size. If you lay out the plans for it you can have the shop include a right angle blend in front to attach a face plate. On my end caps I mounted a nice handle to assist in moving the mono amps.
When I get some shorter caps I will mount them and then be able to put the lids on the amps. In the meantime please note I have no cats or toddlers with little fingers so the open chassis is not too dangerous.
The picture is from 4 years ago when I had a pair of DH-220 circuit cards mounted-- and the sound was really great. Currently I have a pair of DH-200 cards mounted and the sound, again, is really great!
Attachments
Re: Poles in the amp
Dick,
Adding an extra pair of mosfet will increase transconductance -which is good - but will also increase the input capacitance of the output stage -which is less good. In order to reduce the effect of higher capacitance you can increase the driver current (reduce R31 which is 220 ohms). If you reduce R31 value by 1/3 you will have the same equivalent original input capacitance of the output stage and still keep the increase of transconductance...
The heatsink of the driver stage transistor can easily support a 1/3 increae of current...In my DH-200s I have doubled the drive current (R31 = 110) for the output stage with no problem...
A higher drive current is better to feed the starving mosfets...
The above resistor mod is NOT mandatory since it will work also without it.
Good luck!
Dick West said:
Dick,
Adding an extra pair of mosfet will increase transconductance -which is good - but will also increase the input capacitance of the output stage -which is less good. In order to reduce the effect of higher capacitance you can increase the driver current (reduce R31 which is 220 ohms). If you reduce R31 value by 1/3 you will have the same equivalent original input capacitance of the output stage and still keep the increase of transconductance...
The heatsink of the driver stage transistor can easily support a 1/3 increae of current...In my DH-200s I have doubled the drive current (R31 = 110) for the output stage with no problem...
A higher drive current is better to feed the starving mosfets...
The above resistor mod is NOT mandatory since it will work also without it.
Good luck!
Well, i've already started taking one amp apart. I've decided to use the two channels from one amp for the monoblocks, and two channels from the other P230 for the standard stereo amp. It will be a bit more work, but that way the components will be matched. One of my P230's is from the Rockford generation, and the other one is older. They both share the same basic parts, but they used different cap and resistor brands each amp. Not a big deal whatsoever as the values are all the same, but i'm a bit obsessive compulsive...
I have the two heatsink assembly's off, and so far only the transformer is slowing me down. The red goop they used to lock the bolts is really effective.
I have the two heatsink assembly's off, and so far only the transformer is slowing me down. The red goop they used to lock the bolts is really effective.