CREE E3M0065090D or C3M0065090D
Using E3M0065090D for Q1, with IRFP140 in Q2, 24.2 volt rail, 12.7 on drain of Q1. Have 99 ohms on gate stoppers. Just started listening, but sounds fuller than with CREE C3M0160120D in both Q 1&2.E3M0065090D and C3M0065090D have 13 and 16 transconductance respectfully. The E3 has slightly gate charge.
Also placed a 4uf poly film bypassed with a .1uf for input.
Nice clarity, tired of messing around, so will just listen
Using E3M0065090D for Q1, with IRFP140 in Q2, 24.2 volt rail, 12.7 on drain of Q1. Have 99 ohms on gate stoppers. Just started listening, but sounds fuller than with CREE C3M0160120D in both Q 1&2.E3M0065090D and C3M0065090D have 13 and 16 transconductance respectfully. The E3 has slightly gate charge.
Also placed a 4uf poly film bypassed with a .1uf for input.
Nice clarity, tired of messing around, so will just listen
C3M0065090D
Have a C3M0065090D for Q1, and it's companion E3M0065090D in Q2, basically the same part. Have 24.5 volt rails and 12.8 volts on the drain of Q1.
Pretty nice combo, though if you are buying, just get 4 of the C3M0065090D.
I had a pair of the E's, and they are close enough to not buy 4 of the C3M0065090D.
Sound is balanced, bass it there. A nice relaxed sound. Soldered those mosfets in like I plan for them to stay awhile, and I do
They are still burning in, but the sound is filling in as they get more comfortable.
I did add another 33,000uf of filter storage to each channel, so I now have
66,000uf per channel as the final filter reserve for each channel. I have 27,200uf per channel in the first part of the power supply before it goes through a 10mH 5 amp choke per channel.
Have a C3M0065090D for Q1, and it's companion E3M0065090D in Q2, basically the same part. Have 24.5 volt rails and 12.8 volts on the drain of Q1.
Pretty nice combo, though if you are buying, just get 4 of the C3M0065090D.
I had a pair of the E's, and they are close enough to not buy 4 of the C3M0065090D.
Sound is balanced, bass it there. A nice relaxed sound. Soldered those mosfets in like I plan for them to stay awhile, and I do
They are still burning in, but the sound is filling in as they get more comfortable.
I did add another 33,000uf of filter storage to each channel, so I now have
66,000uf per channel as the final filter reserve for each channel. I have 27,200uf per channel in the first part of the power supply before it goes through a 10mH 5 amp choke per channel.
70 ohm is not optimal for R5, much better 78R, in case of use Semisouth parts as Q2.
Later I found degradation when substitute the pot by two fixed resistors in parallel (cheap magnetic ones), so quality on this part has same impact to the final sound as it is R6.
Hello everyone
I have finally collected all the necessary parts for assembling ACA.
The main components that will be used:
- resistors VISHAY Beyschlag 0.6W and ARCOL 5W
- capacitors NICHICON FG 1000uf and FW 3300uf
The cost of all components to be placed on the boards is ~ $ 15.
Waiting for the weekend to start the assembly �� Let's see how it will work with Diatone p-610a (16ohm) - i found info that 16ohm is not the best pair for this amplifier.
It remains to resolve the issue with power supply.
First, I will use MEAN WELL RS-100-24.
Would love to hear some advice on LPS.
On the diyaudioprojects website I found this scheme.
It seems that it fully meets the requirements of the ACA.
I already have components:
- Schottky rectifier STPS8H100D 100v 8a
- capacitors PANASONIC FM 470uf (did not find a suitable 450uf)
- capacitors Wima 0.1uf
- pair of choke HAMMOND 159ZJ
+ I plan to order components.
- trans Toroidy 2x18V 200VA audio grade
- capacitors Epcos Sikorel B41570 10000uf 63v or Kemet Slit Foil 10000uF 63V
Maybe someone has already run this assembly, or can give any comments to it?
Thanks,
Igor
I have finally collected all the necessary parts for assembling ACA.
The main components that will be used:
- resistors VISHAY Beyschlag 0.6W and ARCOL 5W
- capacitors NICHICON FG 1000uf and FW 3300uf
The cost of all components to be placed on the boards is ~ $ 15.
Waiting for the weekend to start the assembly �� Let's see how it will work with Diatone p-610a (16ohm) - i found info that 16ohm is not the best pair for this amplifier.
It remains to resolve the issue with power supply.
First, I will use MEAN WELL RS-100-24.
Would love to hear some advice on LPS.
On the diyaudioprojects website I found this scheme.
It seems that it fully meets the requirements of the ACA.
I already have components:
- Schottky rectifier STPS8H100D 100v 8a
- capacitors PANASONIC FM 470uf (did not find a suitable 450uf)
- capacitors Wima 0.1uf
- pair of choke HAMMOND 159ZJ
+ I plan to order components.
- trans Toroidy 2x18V 200VA audio grade
- capacitors Epcos Sikorel B41570 10000uf 63v or Kemet Slit Foil 10000uF 63V
Maybe someone has already run this assembly, or can give any comments to it?
Thanks,
Igor
Hi, I am using 8 ohm fullrange and also around 24V.
On that LPS circuitery I would increase the two big capacitors from 10.000 to 15.000 uF. and then add further filtering by use of Ubib Salas power supply (here on diyaudio is a group buy). Please note that using a shunt regulation like this, is a voltage decay, and heat, so power transformer must be increased to around 26volt.
On that LPS circuitery I would increase the two big capacitors from 10.000 to 15.000 uF. and then add further filtering by use of Ubib Salas power supply (here on diyaudio is a group buy). Please note that using a shunt regulation like this, is a voltage decay, and heat, so power transformer must be increased to around 26volt.
I agree with the recommendations above to increase the power supply capacitance. I have tried a number of different size capacitors using linear power supplies, and found that the larger ones definitely improve the sound of the amp, as well as reducing the hum. My preferred configuration came to be a 300VA transformer with 20V or 22V secondaries followed by a low Vf bridge rectifier, then a CRCRC capacitor set consisting of 36,000 uF, 1 Ohm, 15,000 uF, 0.11 Ohm, 15,000 uF. Both of the amps I built in the old Hafler chassis now use this style PSU.
Since the ACA is a single rail amp, the dual secondaries in a typical toroidal transformer can be used to make a quasi dual-mono PSU. If you prefer to use chokes, I would suggest placing them after the 36,000 uF bulk supply caps in each channel.
Since the modifications discussed in this thread result in increased bias current around 1.6A, the higher VA rating of the transformer is important to get good regulation. Following these guidelines, you should have an amp that sounds as good or better than a pair of bridged monoblock ACAs using the switching SMPS.
Since the ACA is a single rail amp, the dual secondaries in a typical toroidal transformer can be used to make a quasi dual-mono PSU. If you prefer to use chokes, I would suggest placing them after the 36,000 uF bulk supply caps in each channel.
Since the modifications discussed in this thread result in increased bias current around 1.6A, the higher VA rating of the transformer is important to get good regulation. Following these guidelines, you should have an amp that sounds as good or better than a pair of bridged monoblock ACAs using the switching SMPS.
I need to make a correction to my previous post. The transformer secondary voltage I have been using in my Hafler chassis ACA builds is 24V. After the CRCRC filtering, I'm getting a little over 28V on the PCB. I set the voltage 'bias' at the Drain of Q1 to 14.5V.
I prefer the sound of the IRFP140 Mosfets to the IRFP240, but I still want to try some of the other options that have been mentioned here recently.
I prefer the sound of the IRFP140 Mosfets to the IRFP240, but I still want to try some of the other options that have been mentioned here recently.
Thanks for the recommendations!
I will study information about Ubib Salas.
Also I thought to use Rod Coleman's regulator (version for current 4A to 6.5A ,It's easier to buy in EU)
I previously simulated the circuit (Psud2): transformer 2x20V 250VA (125VA per channel, larger transformer does not fit into the chassis) => cap 15000u => choke 159jz => cap 15000uf
Approximately 27v is obtained, then the Coleman regulator reduces to 24V.
I will study information about Ubib Salas.
Also I thought to use Rod Coleman's regulator (version for current 4A to 6.5A ,It's easier to buy in EU)
I previously simulated the circuit (Psud2): transformer 2x20V 250VA (125VA per channel, larger transformer does not fit into the chassis) => cap 15000u => choke 159jz => cap 15000uf
Approximately 27v is obtained, then the Coleman regulator reduces to 24V.
This is my first time posting here but I was pointed to this thread and found it very informative. I built my initial ACA 1.8 for a friend to use in her system and it has been working very well for her. I was impressed with the sound myself and decided to build two more so I can use it in balanced mode. After reading the earlier parts of this thread I decided to use the premium parts as listed on page 2, post #15. The build went well and in testing the voltages everything looked okay. However, I am running into some problems with the operation which I will detail below:
1. Stereo Mode: Adequate sound is only achieved from the right channel. Very low output can be heard from the left channel and increasing volume brings distortion pretty quickly. This occurs regardless of the position of the toggle switch. If I swap the speaker cables the opposite occurs, so I know the left channel is capable of producing adequate sound, just not when everything is hooked up correctly.
2. Monoblock operation, unbalanced connections: With the toggle switch set to the middle (stereo/balanced mono) or top (bridged) position the left channel produces sound but it is distorted and the right channel has low output. If the sound is in the bottom (parallel) position everything is fine. Speaker cables (outer posts of each amp) and interconnect cables (Chanel A input of each amp) are connected per the 1.6 build guide.
3. Monoblock operation, balanced connections: This one is a little stranger as I get buzz regardless of the position of the toggle switch. Due to balanced operation I have to use a different preamp here so that may be the issue. When the toggle switch is in the up (bridged) or middle (stereo/balanced mono) positions everything sounds is fine. In the bottom (parallel) position no sound at all.
I went back and checked over the wiring which looked okay, I did re-solder the wire to the input jacks and speaker terminals more out or precaution than anything else. I am stumped though so any help would be appreciated.
1. Stereo Mode: Adequate sound is only achieved from the right channel. Very low output can be heard from the left channel and increasing volume brings distortion pretty quickly. This occurs regardless of the position of the toggle switch. If I swap the speaker cables the opposite occurs, so I know the left channel is capable of producing adequate sound, just not when everything is hooked up correctly.
2. Monoblock operation, unbalanced connections: With the toggle switch set to the middle (stereo/balanced mono) or top (bridged) position the left channel produces sound but it is distorted and the right channel has low output. If the sound is in the bottom (parallel) position everything is fine. Speaker cables (outer posts of each amp) and interconnect cables (Chanel A input of each amp) are connected per the 1.6 build guide.
3. Monoblock operation, balanced connections: This one is a little stranger as I get buzz regardless of the position of the toggle switch. Due to balanced operation I have to use a different preamp here so that may be the issue. When the toggle switch is in the up (bridged) or middle (stereo/balanced mono) positions everything sounds is fine. In the bottom (parallel) position no sound at all.
I went back and checked over the wiring which looked okay, I did re-solder the wire to the input jacks and speaker terminals more out or precaution than anything else. I am stumped though so any help would be appreciated.
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@dfoulk, I had updated the binding posts to Cardas and decided to go back to the original binding posts. Turned out this worked for one of the amps. After doing some additional measuring the other amp may have a shorted MOSFET (Q2) or diode (Q3). Waiting on parts to replace them and see what happens.
Tony,
Glad that you got it sorted out! It is always frustrating when things don't work
as they should. I am working on a preamp re-do, and after that is done, I will
put the ACA back in the lineup. I need the gain with the ACA, but my re-vamped B&K has gain enough to use a unity buffer. Just trying to get the
preamp to sound as sweet as my buffer. I will go back to my ACA when that happens.
Glad that you got it sorted out! It is always frustrating when things don't work
as they should. I am working on a preamp re-do, and after that is done, I will
put the ACA back in the lineup. I need the gain with the ACA, but my re-vamped B&K has gain enough to use a unity buffer. Just trying to get the
preamp to sound as sweet as my buffer. I will go back to my ACA when that happens.
It's certainly possible to change R5 and R6 without adding R16. However, R5 and R6 probably have less of an effect by themselves. I've only increased their values to reduce some of the high frequency content on the output when the amp is being driven close to its maximum output. Out of all the changes that were recommended, these are probably the least important.
R16, in combination with the increased value for C4, helps more with a higher voltage on the power supply. If you can find a way to add this on your boards, it is worthwhile.
R16, in combination with the increased value for C4, helps more with a higher voltage on the power supply. If you can find a way to add this on your boards, it is worthwhile.
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