Also I planned on using two power transformer that only have single outputs, four output wires. Is the dual windings neeeded to reduce switching noise on outputs?
Figured if using single output I only need four rectifiers per board and not eight. I can hunt up some Antek iron if needed to reduce power supply hash.
The original stereo My_Ref boards had the polarity going to each channel inverted. Mauro said it lowered the current spikes from the power transformer.
Figured if using single output I only need four rectifiers per board and not eight. I can hunt up some Antek iron if needed to reduce power supply hash.
The original stereo My_Ref boards had the polarity going to each channel inverted. Mauro said it lowered the current spikes from the power transformer.
I figured how to optimize the power transformer connection to the boards. But one question about Mouser.
I have several parts already and my modified BOM came to 127.00 for both channels. The shipping is crazy, 73.75 from either UPS, FedEx, or USPS. The four main filter caps are the only large items. I expected 15 - 20.00 range.
What is shipping to Italy 1,000.00? I am in Houston Texas, I think they are in Mansfield. I might want to see if I can pickup.
I usually order from Digital-Key or Newark. I like Newark, ordered a bunch of the Z series Rubycons from them cheap. Thinking to go back and build a cart to see the difference in cost.
I am a cheap person.
I have several parts already and my modified BOM came to 127.00 for both channels. The shipping is crazy, 73.75 from either UPS, FedEx, or USPS. The four main filter caps are the only large items. I expected 15 - 20.00 range.
What is shipping to Italy 1,000.00? I am in Houston Texas, I think they are in Mansfield. I might want to see if I can pickup.
I usually order from Digital-Key or Newark. I like Newark, ordered a bunch of the Z series Rubycons from them cheap. Thinking to go back and build a cart to see the difference in cost.
I am a cheap person.
Really?
Very strange!Shipping to Italy is free for more-than-50-EUR orders... That's crazy: most items are from U.S.A....
Some parts show this on the MOUSER ordering page:
Shipping Alert: BIG Due to size or weight of the product, your shipping charge may increase.
VPM48-5200 Triad Magnetics | Mouser Nederland
Shipping Alert: BIG Due to size or weight of the product, your shipping charge may increase.
VPM48-5200 Triad Magnetics | Mouser Nederland
I ordered some parts from Parts Connection for the Fremen amps. The 220 ufd BG PF caps and the small value Amtrans caps.
I dug into the parts boxes to hunt components. Found a pair of Cerafine 220 ufd 16v caps and some BG-NX 220 ufd, 6.3 v caps. The NX are non- polar but this should not be an issue.
Is my best bet just use the the BG PK I just ordered?
I dug into the parts boxes to hunt components. Found a pair of Cerafine 220 ufd 16v caps and some BG-NX 220 ufd, 6.3 v caps. The NX are non- polar but this should not be an issue.
Is my best bet just use the the BG PK I just ordered?
@olivosunlight
can you double check the soldering on T101 and T201? On the photos, it looks like some potential solder bridging between the pins? Maybe it's just the photo... Or residue. Also please check if the T101 a T201 are not swapped, e.g. BD139 in place of BD140 and vice versa. Not too hard to mix them up. It's just a shot in the dark, I'm a newbie myself.
can you double check the soldering on T101 and T201? On the photos, it looks like some potential solder bridging between the pins? Maybe it's just the photo... Or residue. Also please check if the T101 a T201 are not swapped, e.g. BD139 in place of BD140 and vice versa. Not too hard to mix them up. It's just a shot in the dark, I'm a newbie myself.
Sincerely, I don't know, I've missed that point on Mauro's boards.
Nevetheless Mauro's boards always used a single diode bridge per channel (per LM3386 on My_Evo) so it's different.
Apart higher cost I suppose 4 trasformers will work as well.
The BOMs will all be shipped for free worldwide, something you added should have triggered extra shipping costs.
The BG NX are the cleanest sounding but have a warm coloration I can't bear.
The BG PK are much more balanced and still clean sounding, I would use those.
Hi,
I'm going to buy in Mouser the Industrial BOM + Evo A Mod,
Dario suggest me to buy the C9 Cerafine,
are there other components that is better to buy immediately?
How do you think about this transformer? 55153-P1S2 TALEMA - Trasformatore: toroidale | TME - Componenti elettronici
Thank you
Matteo
I'm going to buy in Mouser the Industrial BOM + Evo A Mod,
Dario suggest me to buy the C9 Cerafine,
are there other components that is better to buy immediately?
How do you think about this transformer? 55153-P1S2 TALEMA - Trasformatore: toroidale | TME - Componenti elettronici
Thank you
Matteo
Amtrans AMCH instead of Wima FKP2.
For the transformer my suggestion is still for the ones from Conrad.
Sure, take in account that BGs are cleaner than Life, they will somewhat smooth sound.
Nevertheless they sound excellent.
I ve just finished testing Boards and here are results:
Board 2 (just built)
- 33.1/33.0 V
-14.56/14.64 V
-13.97/14.04 V - Zener
- 1.251/1.25 V
0.62 V,
DC output: 0.63 mV
Vled 1.85V
Board 1 (fixed last errors but still another error remaining)
- 33V/33.1
-14.52/14.5
-13.96/13.90 - Zener
1.252/1.25
0.594 V
DC output: 23-15 mV
and Led was light for some min then gone, Vled is around 0.7 V
Please let me know about my results, are they OK?
and what should i check on Board 2? can we use both Leds on board and Ext Led?
BTW: This solder paste damaged my last boards. Pass han Pro'skit 8S005 | CONG TY CỔ PHẦN THƯƠNG MẠI ĐIỆN TỬ DAN XUAN
Board 2 (just built)
- 33.1/33.0 V
-14.56/14.64 V
-13.97/14.04 V - Zener
- 1.251/1.25 V
0.62 V,
DC output: 0.63 mV
Vled 1.85V
Board 1 (fixed last errors but still another error remaining)
- 33V/33.1
-14.52/14.5
-13.96/13.90 - Zener
1.252/1.25
0.594 V
DC output: 23-15 mV
and Led was light for some min then gone, Vled is around 0.7 V
Please let me know about my results, are they OK?
and what should i check on Board 2? can we use both Leds on board and Ext Led?
BTW: This solder paste damaged my last boards. Pass han Pro'skit 8S005 | CONG TY CỔ PHẦN THƯƠNG MẠI ĐIỆN TỬ DAN XUAN
Hi!
A week ago I finished the construction of the My_Evo Rev. A.
After over 40 hours of listening with a passive TVC preamplifier, I am very impressed with the sound quality. Sound control is remarkable.
For less than 450,00 Euros, I think it's almost a miracle.
I would like to remember and thank Mauro Penasa's brilliant intuition on how to use in an original way a LM3886 and the great work of implementation and fine tuning done by Dario Inserra. What have they done!? My god, they did!
For budget reasons I used the Mouser industrial BOM with the exceptions of C9 (Cerafine on Ebay less than 6,00 Euros) and C13 (a friend of mine gave a couple of Mundorf Supreme to me). Transformers are Triad Magnetics, the cheapest ones found by Mouser. Nothing less than other more expensive and famous, they work perfectly.
Always for budget reason I choose as enclosure a Galaxy 31x28x8cm (less than 40,00 Euros). According to Dario, this is the minimum solution to contain the amplifier. The only recommendations are to use 20mm spacers to bring the LM3886 to a height that does not encounter grooves on the heatsinks and use high quality thermal compound (I used Arctic MX-4) to achieve the best thermal coupling.
The last week in Rome, where I live, we have had very high temperatures, over 35 degrees Celsius. Under these conditions, the heatsinks were warm, but not very hot.
Now the temperature is near or below 30 degrees Celsius and heatsinks are tepid-warm. My speakers are three-way closed box, 91 dB, minimum impedance 4 ohm. Not a very difficult load.
After first power up DC offset were about -4,0mV and -6,5mV. After 30 hours of listening were about -4,5 and -8,0 mV (this is the only value I don't like too much). I hope DC offset will stabilize (possibly within + or - 10mV)...
The amplifier has never made noises, electric discharges, it is totally silent and has not presented any anomalous overheating.
My little problem is the fuse: I've bought Schurter ceramic ones, slow blow (from datasheet: time-lag T, high breaking capacity - ceramic tube, 1,25A 250V).
In a week, three times, turning on the amplifier, I found the fuses broken. What do you think is the cause? Can I use a 1.6 or 2 amp fuse in the hope that it will last? Or is it dangerous?
The only thing I added to the project are two X2 capacitors (0,01uF 275VAC) mounted on the bipolar switch to avoid burning the contacts. Are they the possible cause? Or I was wrong to choose the type of fuse?
Thank you all for your attention
Giacinto
A week ago I finished the construction of the My_Evo Rev. A.
After over 40 hours of listening with a passive TVC preamplifier, I am very impressed with the sound quality. Sound control is remarkable.
For less than 450,00 Euros, I think it's almost a miracle.
I would like to remember and thank Mauro Penasa's brilliant intuition on how to use in an original way a LM3886 and the great work of implementation and fine tuning done by Dario Inserra. What have they done!? My god, they did!
For budget reasons I used the Mouser industrial BOM with the exceptions of C9 (Cerafine on Ebay less than 6,00 Euros) and C13 (a friend of mine gave a couple of Mundorf Supreme to me). Transformers are Triad Magnetics, the cheapest ones found by Mouser. Nothing less than other more expensive and famous, they work perfectly.
Always for budget reason I choose as enclosure a Galaxy 31x28x8cm (less than 40,00 Euros). According to Dario, this is the minimum solution to contain the amplifier. The only recommendations are to use 20mm spacers to bring the LM3886 to a height that does not encounter grooves on the heatsinks and use high quality thermal compound (I used Arctic MX-4) to achieve the best thermal coupling.
The last week in Rome, where I live, we have had very high temperatures, over 35 degrees Celsius. Under these conditions, the heatsinks were warm, but not very hot.
Now the temperature is near or below 30 degrees Celsius and heatsinks are tepid-warm. My speakers are three-way closed box, 91 dB, minimum impedance 4 ohm. Not a very difficult load.
After first power up DC offset were about -4,0mV and -6,5mV. After 30 hours of listening were about -4,5 and -8,0 mV (this is the only value I don't like too much). I hope DC offset will stabilize (possibly within + or - 10mV)...
The amplifier has never made noises, electric discharges, it is totally silent and has not presented any anomalous overheating.
My little problem is the fuse: I've bought Schurter ceramic ones, slow blow (from datasheet: time-lag T, high breaking capacity - ceramic tube, 1,25A 250V).
In a week, three times, turning on the amplifier, I found the fuses broken. What do you think is the cause? Can I use a 1.6 or 2 amp fuse in the hope that it will last? Or is it dangerous?
The only thing I added to the project are two X2 capacitors (0,01uF 275VAC) mounted on the bipolar switch to avoid burning the contacts. Are they the possible cause? Or I was wrong to choose the type of fuse?
Thank you all for your attention
Giacinto
