I got the parts. Should I just order a case and a cooler with predrilled and threaded holes for the transistors? How much should that cost?
Also I'd like to add an attenuator in case I'll want to use it without a preamp. Which potentiometer should I use? Should I just connect it before input signal? Do I need a soft power on circuit?
If your Sources can drive a 10k pot and the interconnect capacitance, then use a 10k dual track log law pot.
Isolate the pot from the amplifier with two input filters, a low pass and a high pass.
Isolate the pot from the amplifier with two input filters, a low pass and a high pass.
Hi Lamir, any progress? Are you planning using 1 or 2 transformers?
I have been busy and have made no progress until today. I started soldering and the first board is progressing nicely. I need to get the small cooling sinks next. I think my local electronics store have something I can use - have to go and check.
I will use a soft start circuit.
I have been busy and have made no progress until today. I started soldering and the first board is progressing nicely. I need to get the small cooling sinks next. I think my local electronics store have something I can use - have to go and check.
I will use a soft start circuit.
And yes, found some. I decided to glue them onto the PCB with small blob of glue. So, they are removable but now they will not be supported only by the transistors.
The transistors are here just to align the sinks correctly while glue is drying. I will add the thermal paste before I solder them on.
An externally hosted image should be here but it was not working when we last tested it.
Ps. incase you wonder: no the sinks do not touch the resistor solder pads.
And today I took a break from work and now first one is finished and the second one is under work.
An externally hosted image should be here but it was not working when we last tested it.
Hi Tony! I have build many of these amp kits and it is my favorite one😉.
I would suggest you to change C1 for a NP with high quality since that one is the input cap. mine is a Sonicap 4.7uf and I put them on the RCA terminals since they are way too big to fit on the board. When you remove C1, make sure you put a jumper on the board (C1). if you have any questions, feel free to PM me.
Hi, yes I've seen some of your postings about these and it might be that I partly chose this kit because of you.
Thanks for the tip, sent you PM.
Hi lamir! you can add a 10K potentiometer, I use a 10K TKD potentiometer on mine and I can not be ANY happier. I use a 320vac toroidal transformer and 42vdc per rail. I just put a thermistor in line on the primaries of transformer. Any questions, feel free to PM me.
PSS: Alfred is very nice person to deal with (HDamp.com)
Hi again.
First I did't get what you meant but after looking at pics of your amp I think I got it. The white big caps placed on the rear panel near RCA-terminals are the Sonicaps - right? And then you just replaced the C1 with a jumper wire?
I infact did install Elna Silmic II instead of the original Panasonic in mine. Why? Because I had some and I like trying stuff out 😉 But, I might give your suggestion a try if I can locate similar Sonicaps somewhere.
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BINGO!!!!😉. That is exactly what I did.
I am with you, if you had them on hands....Why not try right?
I always try to stay "away" or better said...try to use electrolytic caps as fewer as I can. They will dry out sooner or later and they will "shift" with time😱
in some circuit you must use electrolytic caps( I understand that) but in this case (input) you can use a high quality Polypropylene cap.
Good choice! The first time I try the Sonicap was when I build some NXV200 amp kit from Aussie amplifier, Anthony always uses these caps in his amps and He recommended me to try, so I try them and I like them very much... since then I always use them for input caps.
I have build many amp kits and the best I have ever listened is the M400, I also build a couple T300 from hdamp.com too, but the M400 was the winner😛
it is very important to use a good power supply. in my case, I always go for Mundorf audio grade caps. I "experimented" with many power supply caps. I did a few regulated and a few un-regulated using good parts and I concluded that if you use "high quality" caps, the un-regulated power supply will sound excellent and it will be simpler, more reliable. I know some will jump on this, but I am set to a "good" un-regulated power supply. This is like speakers crossover...some crossover are more complex(24db) and some are simpler (6db)...it is all in the quality of the drivers and crossover parts. My B&W speakers use a first order crossover, but the drivers are very good to be used with just a first order crossover....I find complex crossovers "muffle" too much the sound. Class A amplifiers are simple and sound excellent(most of them) the only thing that I do not like about them is most of the power goes to heat...😱.
PS: I used the NP Black gate(rare now) But I liked the Sonicap better.
How much of a difference does having separate transformers makes instead of one? Will it be noticeable?
If the transformer is undersized, then going to two will make quite a big difference.
If the transformer is oversized, then going to two will make a very small difference.
However there is another benefit. Grounding can be simpler and thus more likely to be successful, = no hum nor buzz.
This particularly applies for actual monoblock amplifiers.
If the transformer is oversized, then going to two will make a very small difference.
However there is another benefit. Grounding can be simpler and thus more likely to be successful, = no hum nor buzz.
This particularly applies for actual monoblock amplifiers.
I have 2 more questions: will it be possible to use a 3 states ON switch for a soft start circuit so the middle state will fill the big caps through a resistor to decrease current? Will it be possible to use a headphone DAC with it? I know I'll have to add an attenuator, but what are the requirements from the DAC?
I am using a thermistor in place before transformer.You can always use a soft start circuit, but I do not find it necessary. if you are going to use a really HEFTY power supply, then you should use a soft start. as I said before, these amp kits DO NOT make any popping noises at turning on or at turning off, and dc offset can be set to steady ZERO mv.... also if you put your ears "touching" the tweeter/woofer of your speakers without any sources connected, you will not hear static, back noises, hissing, farts etc.😛
For the headphone...I have not try😱
This amp kit was designed very well and for what I was told by the "founder" all started with a prototype using some circuit topology of amps costing a few thousands then it was simplified and with the help of a few "smart" fellas it was improved even better. is this a new topology?....NO! it is just a better designed amp kit than "many" I have seen or try!.
PS: Not too long ago, I build another M400 for a friend, He loved it😛. But What I noticed was it had some static noise. since I know these M400 are dead silent...I new it was nothing to do with the amp, so I started troubleshooting and I found it was with power supply (transformer) I replaced that old T transformer with a toroidal transformer and the back noise went away. Now you will never know if it is on or off😀 (luckily I put an led light... lol).
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