This is my build of the Dartzeel amp. The chassis, transformer and large caps are from a Bel 1001. I have added the ESP cap multiplers, one set for each channel to compensate for the low PSRR. It is under initial testing, it works and DC offset adjusts down to under 5mV no problem and seems quite stable. I haven't tried listening to it yet.
Voltages are circa 42.5V at the filter caps and 40V on the cap multiplier outputs, so I am not running mine at such higher rail voltages as the original design.
Voltages are circa 42.5V at the filter caps and 40V on the cap multiplier outputs, so I am not running mine at such higher rail voltages as the original design.
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Nice build!
df_genius looks like you might have he same amp boards as me.
Something like 70-80€ on ebay or am I mistaken?
Anybody happen to know where I could get PCBs for capacitance multipliers?
I have gotten really lazy with PCB etching and generally dislike the prototype boards
Even if it is a simple circuit.
Cap multipliers are generally cheaper and more compact than huge inductors so I like them
df_genius looks like you might have he same amp boards as me.
Something like 70-80€ on ebay or am I mistaken?
Anybody happen to know where I could get PCBs for capacitance multipliers?
I have gotten really lazy with PCB etching and generally dislike the prototype boards
Even if it is a simple circuit.
Cap multipliers are generally cheaper and more compact than huge inductors so I like them
These are the boards I bought, I'd not used that website before but put them on a credit card and they arrived ok:
DARTZEEL DC 35V 55V 470UF/100V 200W+200W Superpower Amplifier Board A Pair - Free Shipping - ThanksBuyer
I am using a PETP input cap and replaced the low value capacitors with polystyrene. I replaced the 470uF 100V local power supply caps with 2200uF 50V. Despite the heatsink being smaller than the original Dartzeel mine only runs warm to the touch after about 30 mins. I am getting hum on the output of a few mV on both channels, I think is is coming from the transformer although I haven't put my scope on it yet, the transformer is audibly buzzing.
My cap multipliers are done P2P, they weren't hard, I glued the capacitors to the heatsink.
On 40V rails I measure around 4mV on each emittor resistor, so each output device is biased to around 18mV. The driver mje15034/5 transistors seem to produce more heat at idle.
DARTZEEL DC 35V 55V 470UF/100V 200W+200W Superpower Amplifier Board A Pair - Free Shipping - ThanksBuyer
I am using a PETP input cap and replaced the low value capacitors with polystyrene. I replaced the 470uF 100V local power supply caps with 2200uF 50V. Despite the heatsink being smaller than the original Dartzeel mine only runs warm to the touch after about 30 mins. I am getting hum on the output of a few mV on both channels, I think is is coming from the transformer although I haven't put my scope on it yet, the transformer is audibly buzzing.
My cap multipliers are done P2P, they weren't hard, I glued the capacitors to the heatsink.
On 40V rails I measure around 4mV on each emittor resistor, so each output device is biased to around 18mV. The driver mje15034/5 transistors seem to produce more heat at idle.
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I recently finished one of these amplifies using the claimed "1:1" copy pcb boards. They are fairly easy to build, probably one of the easiest amplifiers I attempted to put together. These sound fantastic, probably one of the best chinese copy cat offerings. I dont know how the other versions sound but this one is definitely worth building.
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I have only been listening to this amp for about 10 days. For the break in period its in my living room right now powering a set of M&K satellites. I can compare it to the Sony receiver that normally powered the M&Ks. The receiver is rated 100 watts per channel which is the same as the NHB-108 (100w into 8ohms). The M&Ks never sounded dynamic to me and it didnt really bother me since they were bookshelf sized satellites, I didnt expect them to blow me away. I do have a pair of 8" subs to help them out. Initially I was a bit disappointed with the Dartzeel because the M&K sounded muddy and veiled on the first audition. I quickly realized the subs were now crossovered too high and I had to set the crossover point from 100hz to 50hz and back the gain down a lot. Eventually I even switched the subs off. Suddenly these satellites got a bunch of low end grunt that they never had before. The toms and kick drums were now on point and the speakers became very dynamic, much more musical. The sound is crisp, airy and coherent, I even have imaging now! Before demanding passages were mishmashed with instruments stepping on top of each other, I blamed it on the small living room and the close placement of the speakers to the back wall. Even my wife pointed out the M&Ks sounded like my speakers in my audio room now. So far I can say Im blown away, eventually I want to test this amp in my audio room on a bigger set of speakers and I might even move these M&Ks into the audio room to see if they will sound even better in there.
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Maybe something to do with the lowish Df...
Looks like a nice amp, although a Sony receiver as a frame of reference is as low as it gets.
Heard Dartzeels many times at shows, but always feeding ceramic midranges...couldn't make heads or tails from the sound as ceramic just mashes my ears into pulp.
The Sony is the only thing I could compare it to, later on I can compare it to a GM Telos Clone. In the past I did compare the Sony to other amplifiers like a MYRef LM3886 and a Forte 1A (pure class A) and even though the later 2 amps were clearly better it wasnt like comparing apples to oranges.
I could not resist so I bought the kit from ebay. It works, it produces heat, it makes music. I have only tested on cheap speakers, as I do not have final powers supply. But it sounds fabulous.
One problem though. One channel has not problem, I can precisely adjust zero volts on the output, as the pot is right in the middle, and easily multi turn goes to positive and negative territory. Other channel, on the other hand, has ~200mV DC, and the pot is already in its end position. Any suggestions?
One problem though. One channel has not problem, I can precisely adjust zero volts on the output, as the pot is right in the middle, and easily multi turn goes to positive and negative territory. Other channel, on the other hand, has ~200mV DC, and the pot is already in its end position. Any suggestions?