Update to as-implemented parts list:
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** As-Implemented Parts List **
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C1: Nichicon Aluminum Electrolytic Capacitors - Snap In 35volts 4700uF 20%
C2: Nichicon Aluminum Organic Polymer Capacitors 16V 1000uf 20%
C4: Nichicon Aluminum Organic Polymer Capacitors 100uF 35V 20%
C101: Cornell Dubilier – CDE Mica Capacitors 10pF 500V 5%
R3/R4: Vishay / Dale Wirewound Resistors - Through Hole 3watts 0.56ohms 1%
R11: Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 20Kohms 1%
R12: Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 90.9Kohms 1%
R16 (Bridge Resistor): Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 68.1Kohms 1%
Q1/Q2: FQH44N10-F133
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** NEW: As-Implemented Parts List **
=========================
Same as above but:
Swapped out the C101: Cornell Dubilier – CDE Mica Capacitors 10pF 500V 5%
For C101: Silver Mica Capacitors 10pF 500V 5% (this was already one of the top picks as recommended by TungstenAudio, but at the time I could only find the Cornell Dubilier.)
=========================
I could only find the Silver Mica Capacitors directly or indirectly from thetubestore.com and there is a minimum order requirement, but the new Silver Mica capacitors really seemed to make a difference, just more smooth and balanced sound overall.
=========================
** As-Implemented Parts List **
=========================
C1: Nichicon Aluminum Electrolytic Capacitors - Snap In 35volts 4700uF 20%
C2: Nichicon Aluminum Organic Polymer Capacitors 16V 1000uf 20%
C4: Nichicon Aluminum Organic Polymer Capacitors 100uF 35V 20%
C101: Cornell Dubilier – CDE Mica Capacitors 10pF 500V 5%
R3/R4: Vishay / Dale Wirewound Resistors - Through Hole 3watts 0.56ohms 1%
R11: Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 20Kohms 1%
R12: Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 90.9Kohms 1%
R16 (Bridge Resistor): Vishay / Dale Metal Film Resistors - Through Hole 1/4watt 68.1Kohms 1%
Q1/Q2: FQH44N10-F133
=========================
=========================
** NEW: As-Implemented Parts List **
=========================
Same as above but:
Swapped out the C101: Cornell Dubilier – CDE Mica Capacitors 10pF 500V 5%
For C101: Silver Mica Capacitors 10pF 500V 5% (this was already one of the top picks as recommended by TungstenAudio, but at the time I could only find the Cornell Dubilier.)
=========================
I could only find the Silver Mica Capacitors directly or indirectly from thetubestore.com and there is a minimum order requirement, but the new Silver Mica capacitors really seemed to make a difference, just more smooth and balanced sound overall.
Great to see independent experimentation and validation.
I started using those silver mica caps in my bass guitar effects pedals, as well as a tube-based bass guitar preamp.
Hi DIYaudioers-
Happy Thanksgiving and thanks for all the work going into this thread. i have built some ACA 1.6 amps and have been running them in parallel mono. I am now looking to “improve” them a bit and have a bit of a novice question. As I look to ordering parts from Mouser, I would like to clarify if, for C1 I should get the parts that end in AK or BK? Also, the third letter from the left varies, (y, b, z, a), does that matter? For C4 there are also a few choices ending in s1, S1PX or S1KX, which is recommended?
Looking forward to soldering, Thanks!
Happy Thanksgiving and thanks for all the work going into this thread. i have built some ACA 1.6 amps and have been running them in parallel mono. I am now looking to “improve” them a bit and have a bit of a novice question. As I look to ordering parts from Mouser, I would like to clarify if, for C1 I should get the parts that end in AK or BK? Also, the third letter from the left varies, (y, b, z, a), does that matter? For C4 there are also a few choices ending in s1, S1PX or S1KX, which is recommended?
Looking forward to soldering, Thanks!
For C1 I used the LKG1V472MESBBK. The major differeces that I can see are diameter sizes. The LKG1V472MESBBK is 30mm in diameter and was a perfect fit.
For C4 I used the 647-RL81V101MDN1. Again, the major difference looks to be diameter size. the 647-RL81V101MDN1 is 8mm in diameter and was a perfect fit.
For R3 and R4, is a ceramic cap okay for audio use, or should I be steering towards wirewounds instead? Thanks.
Meant to say ceramic resistor. I looked into these and they seem to be aimed at crossovers more than inside a circuit.
I prefer metal oxide resistors in those positions, such as the ones made by KOA Speer: mouser p/n 660-MOSX3CT631RR68J .
Be sure to measure the spacing between the holes for the resistor leads, on your PCB. You don't want to accidentally order a resistor whose body is longer than the lead-to-lead hole spacing.
Be sure to measure the spacing between the holes for the resistor leads, on your PCB. You don't want to accidentally order a resistor whose body is longer than the lead-to-lead hole spacing.
can I ask why ? I know the Koa is a good resistor but mox on speaker tw is a no go for me
Thanks, Mark.
As I get closer to getting my parts list, I have two more questions:
1) I expect that I disassemble each amp (I have two) by sitting it on it's side and desoldering the 8 wired connections from the rear panel for starters.
2) Will I need to replace the Keratherm under Q1 and Q2?
Thanks!
As I get closer to getting my parts list, I have two more questions:
1) I expect that I disassemble each amp (I have two) by sitting it on it's side and desoldering the 8 wired connections from the rear panel for starters.
2) Will I need to replace the Keratherm under Q1 and Q2?
Thanks!
1) It depends on what parts you want to replace, but assuming most are on the amp boards themselves... and that you don't have any of the SMPS filter boards, and/or that you don't want to add a linear power supply... I'd just take the sinks off, remove the boards from the sinks, and do the necessary work w/o any desoldering. However, if I did feel the need to desolder, I'd do it on the board. Just my preference.
2) It depends how careful you are, but I've generally found it to be unnecessary.
2) It depends how careful you are, but I've generally found it to be unnecessary.
I am going with the dual 24V SMPS / filter approach for a stereo package. Since I could not procure any FQH44N10, I looked at the FQA series and found a FQA70N10, that is close in some respects to the FQH44N10. The FQA70N10 will be used for Q1 with IRFP140NPBF in Q2. I managed to find in my spares a couple of 1000uF 16V Silmic II caps to use in C2 and a couple of 100uF 50V Nichicon FG to use in C4.
My clone boards will not allow me any resistor upgrades for higher voltage, so going to build a nice dual mono package.
Great thread to read, and learn from.
MM
My clone boards will not allow me any resistor upgrades for higher voltage, so going to build a nice dual mono package.
Great thread to read, and learn from.
MM
they have a bunch of fqh44n10 at arrow https://www.arrow.com/en/products/fqh44n10-f133/on-semiconductor
@Zamjazz, Too late, Mouser had all I needed except the FQH's, so did the diy thing and found a comparable substitute. Thanks for info about Arrow, will keep in mind for future use.
Thanks for the link to Arrow. I was initially thrown off by the message on their site: "Import Tariff: May apply to this part if shipping to the United States" which sounds like they are not in the US. (I am.) But they are in the US, so I'm good to go.
For the FQH44N10-133, is it worth it to buy a handful of these and matching for IDSS? Or are they more consistent and I shouldn't worry about it?
Thanks!
FQH44N10-133 is an enhancement mode MOSFET so its IDSS is, by definition, zero. In real life, it's zero plus whatever leakage current the test program allows, without rejecting the part and preventing it from shipping to a customer.
IDSS is measured on JFETs, not MOSFETs.
For enhancement mode MOSFETs, hobbyists sometimes match Vgs_threshold and/or transconductance. Here is an article on passdiy.com that touches upon some of the ideas.
IDSS is measured on JFETs, not MOSFETs.
For enhancement mode MOSFETs, hobbyists sometimes match Vgs_threshold and/or transconductance. Here is an article on passdiy.com that touches upon some of the ideas.
Wow, thanks Mark. I appreciate that.
I see you mention "sometimes match vgs_threshold," and the article in the link mentions matching as being more important for input MOSFETs. I get the idea that the power MOSFETs in this case likely do not need a lot of matching work to be effective. (I hope I read this correctly!)
Thanks again.
I see you mention "sometimes match vgs_threshold," and the article in the link mentions matching as being more important for input MOSFETs. I get the idea that the power MOSFETs in this case likely do not need a lot of matching work to be effective. (I hope I read this correctly!)
Thanks again.
Hello, I have a question. What wattage of resistors are needed for the 0.22 ohm? R101/R102 in this Lm1084 regulator circuit?