Is there any valid reason for the choice of transformer and reservoir cap size?
Would 10 000uF be worse and 100 000uF be better or maybe not. Is 500VA enough for powering 150 watt per channel amp with 33 000 uF per rail.
Did you make any useful measurements to confirm if your choice is good, bad or just a personal preference?
Hello Mr. Nico Ras,,,This 1 channel that I,ve built so far is my test amp for this board each amp per channel will have a total of 66k mfd and a 500va power tranformer in addiction I,ve Moded the output slighty, The tip,s 142 is a good transistor, but there are better devices for this device. check the spec,s for a mjh6284 then you,ll see what I mean,, Regards Evette
Evette,
The On-Semicondutor MJH6284 do not look like they are readily available. Did you have these sitting around for some time or are they still available for purchase? Anybody know the answer to this? I see both Digikay and Mouser do not list a price for this item. Anyone with a source or is there an even better current part that we should be looking at. Lastly do we need to make any changes to any values on the board to take maximum advantage of a change such as this? I see that the dc power should be increased with this transistor but what else should change?
Steven
The On-Semicondutor MJH6284 do not look like they are readily available. Did you have these sitting around for some time or are they still available for purchase? Anybody know the answer to this? I see both Digikay and Mouser do not list a price for this item. Anyone with a source or is there an even better current part that we should be looking at. Lastly do we need to make any changes to any values on the board to take maximum advantage of a change such as this? I see that the dc power should be increased with this transistor but what else should change?
Steven
Dear Evette,
what I meant was and I am very interested in knowing how the amplifier performs with the choice of your power supply, and what inspired your choices, was there any calculations that you followed or experience that caused you to choose the specific value.
Were you influenced by other constructors or Harrison or read somewhere that gave rise to your reasoning. No disrespect meant at all Evette I am curious because of all that is said in the Power Supply tread.
Hello Mr.Nico Ras, first of all I should explain that this 1 channel was built using all junk parts that were collected over many years you know old tv sets radios anything I couls salvage. I haven,t collected information from others or mr. harrison. Nor have I read any power supply thread. The changes I made werte because I wanted to really open this amp up,,The pcb,s that Mr. Harrison was so kind to give to me I felt that he had given me the tools to begin with so I simply took it to the next level. Evette
Harrison,
A couple of questions for you or anyone else. I found a discrepancy between another part number on the BOM, C3 & C12 are supposed to be 33uF capacitors. The parts I received are 47uF instead and read as part # PLV1J470MDL1TD. I am coming up with UEP1J330MPD-ND but not sure if this is correct? What should the correct number be. Also I ended up with the wrong fuse holders for the boards. Does anyone have the part number for the correct parts? Otherwise I am close to completing the boards, just wondering if I am going to change the output transistors to what Evette is using..... Haven't built the power supply so it would be a perfect time to change devices. I am thinking that with the devices Evette is using the output power is also increasing, is that correct or is it just running on a higher voltage?
A couple of questions for you or anyone else. I found a discrepancy between another part number on the BOM, C3 & C12 are supposed to be 33uF capacitors. The parts I received are 47uF instead and read as part # PLV1J470MDL1TD. I am coming up with UEP1J330MPD-ND but not sure if this is correct? What should the correct number be. Also I ended up with the wrong fuse holders for the boards. Does anyone have the part number for the correct parts? Otherwise I am close to completing the boards, just wondering if I am going to change the output transistors to what Evette is using..... Haven't built the power supply so it would be a perfect time to change devices. I am thinking that with the devices Evette is using the output power is also increasing, is that correct or is it just running on a higher voltage?
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Hi Evette,
A friend of mine in Seattle would like to listen to your amp. Or you could make him one as he cannot assemble
PM me.
Evette,
I looked on the site for those mjh6284 transistors and I assume that you had the earlier case configuration. The ones that are available as of June of this year are different but I am not sure that it would make any difference? Is the case the only difference and is the heat transfer going to be affected by the larger case on the device? I'm a babe in the woods on understanding all the factors of choosing a power transistor and I can see the Darlington circuit in the schematics but I will need to read much more before I would know one designs advantage over another. I am counting on the smart people here to steer me right. The more clean power I can get out of the design the better as I am working with loudspeakers with great frequency response and low efficiency of about 86db at 1 watt and 4 ohms. I also have the same in an 8 ohm voicecoil but the efficiency is about identical with the change of impedance as the weight of the voicecoil makes them about even.
Steven
I looked on the site for those mjh6284 transistors and I assume that you had the earlier case configuration. The ones that are available as of June of this year are different but I am not sure that it would make any difference? Is the case the only difference and is the heat transfer going to be affected by the larger case on the device? I'm a babe in the woods on understanding all the factors of choosing a power transistor and I can see the Darlington circuit in the schematics but I will need to read much more before I would know one designs advantage over another. I am counting on the smart people here to steer me right. The more clean power I can get out of the design the better as I am working with loudspeakers with great frequency response and low efficiency of about 86db at 1 watt and 4 ohms. I also have the same in an 8 ohm voicecoil but the efficiency is about identical with the change of impedance as the weight of the voicecoil makes them about even.
Steven
. A lot of members are missing out because they cannot assemble these amplifiers. They would prefer modules or complete builds. I welcome constructive ideas on how to fix this
Inorder for me to focus on research rather than these issues I need partners
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I understand Harrison. I am in the middle of a beryllium dome tweeter development project and what am I doing building an amplifier? But I am learning so it is worth much to me in that regards.
Not to be racist in the least. but Chinese hands would build it cheaper than all the rest of us are going to do this for.......
Not to be racist in the least. but Chinese hands would build it cheaper than all the rest of us are going to do this for.......
The universe has many mysteries, could it be possible that the success of the tweeter will be hinged on that amplifier
<joking>