The markings on PCB are correct, but you're right, the pin is actually Pin 5 not 1, also not connected, I've used same (wrong) name used by Feckie without checking.
Feckie, apart the wrong name, all suggestions still apply, pin 5 is not connected too.
When turned on, relay does not click.
Measuring between PGND and OUT i get 3.62v. Does this suggest a problem further back or is it related to the LM318M?
Measuring between PGND and OUT i get 3.62v. Does this suggest a problem further back or is it related to the LM318M?
Measure the voltage across the relay back emf diode.
It should be around the relay coil voltage.
It should be around the relay coil voltage.
Feckie, I just completed a similar troubleshoot. What helped me enormously was taking the time to trace out paths on sections of the schematic and silkscreen. Although this was a V1.3 MyRef, you may be able to get some ideas looking at posts before and after this post. I also had to probe for continuity from each LM318 pin to it's next/nearest component - and beyond.
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sorry buddy but im a noob of the highest proportions 🙂
when you say passives could you give me an example.
I havent measured the passives yet but i did resolder the board and something interesting happened.
In order:
1. Plugged in the board
2. Powered on and i heard the click and led lit up
3. Measured C102 and C202
4. 1 had 14.4v (cant remember exact but it was within range)
5. The other had .5v again.
6. Took off the secondaries and checked the bottom of the board and didnt see anything obvious.
7. Put secondaries on again and there was NO click or LED.
8. Played around for a while and discovered that the secondary pairs position is directly related to whether i get a click or not.
For example
set 1 (green and red) on AC2 and NAC2 and set 2 on AC1 and NAC1 = Relay and LED on
set 2 (Blue and brown) on AC2 and NAC2 and set 1 on AC1 and NAC1 = no relay or LED
Now for something that you all probably know but i dont. The secondary pairs have a protective coating on the wire, so it may look exposed but a continuity test will not beep. Tap it on the end with the copper exposed and i get a beep.
This hasnt been tested on the amp just yet but will be in the next 30 minutes. Post again shortly
In order:
1. Plugged in the board
2. Powered on and i heard the click and led lit up
3. Measured C102 and C202
4. 1 had 14.4v (cant remember exact but it was within range)
5. The other had .5v again.
6. Took off the secondaries and checked the bottom of the board and didnt see anything obvious.
7. Put secondaries on again and there was NO click or LED.
8. Played around for a while and discovered that the secondary pairs position is directly related to whether i get a click or not.
For example
set 1 (green and red) on AC2 and NAC2 and set 2 on AC1 and NAC1 = Relay and LED on
set 2 (Blue and brown) on AC2 and NAC2 and set 1 on AC1 and NAC1 = no relay or LED
Now for something that you all probably know but i dont. The secondary pairs have a protective coating on the wire, so it may look exposed but a continuity test will not beep. Tap it on the end with the copper exposed and i get a beep.
This hasnt been tested on the amp just yet but will be in the next 30 minutes. Post again shortly
scraping off the coating I get this
C102 = 14.2v
C202 = 14.5v
🙂 🙂 🙂 🙂 🙂 🙂 🙂
Now with all that has happened have i killed the lm318m?
Could the coating problem have caused the 3886 blowing up originally?
Could be a pain removing lm318m due to the pad lifting but hell at least i got somewhere!
C102 = 14.2v
C202 = 14.5v
🙂 🙂 🙂 🙂 🙂 🙂 🙂
Now with all that has happened have i killed the lm318m?
Could the coating problem have caused the 3886 blowing up originally?
Could be a pain removing lm318m due to the pad lifting but hell at least i got somewhere!
The coating on the transformer leads is the enamel of the enameled copper winding wire.
It is pretty tough and must be scraped off and then soldered immediately to prevent a hard corrosion building up. Ensure it is scraped off all the way around the wire circumference.
You need to measure the voltage on the back emf diode to check if the relay is being asked to close or if the protection is holding the relay open.
Once you know that we can help debug either the relay drive circuit or the amplifier circuit.
We and you need to know which is causing the silence on power up.
It is pretty tough and must be scraped off and then soldered immediately to prevent a hard corrosion building up. Ensure it is scraped off all the way around the wire circumference.
You need to measure the voltage on the back emf diode to check if the relay is being asked to close or if the protection is holding the relay open.
Once you know that we can help debug either the relay drive circuit or the amplifier circuit.
We and you need to know which is causing the silence on power up.
I can do that tonight if you like.
Just to be clear one pair of secondaries wasn't giving any power at all because of this coating. After scraping it off it powered correctly.
I had soldered on the 3886 thinking i had found the problem, i didn't turn it on because as i wanted to get a confirmation from here. No probs i will take it off and get the measurement for you.
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A couple of questions to experienced diyers!
Here is my situation...
I am in process of completing MyRefs FE from the latest group buy. I already finished ZaphAudio ZDT3.5 and plan to bi-amp them with MyRefs FE for HF+MF combo and Audiosector LM4780 parallel kit for LF. No extreme listening levels are planned.
Now the questions...
Could someone recommend me a good DAC for MyRefs FE + ZDT3.5's? I am looking at the NOS DDDAC1794 at the moment. Would it be overkill or just right match for my speakers and amp? Or I should consider something else...?
The questions are due to the lack of personal experience with good quality setup. I just started assembling mine from scratch. The most probable source of music is PC.
Any ideas/suggestions are welcome!
Thank you!
Oleg
Here is my situation...
I am in process of completing MyRefs FE from the latest group buy. I already finished ZaphAudio ZDT3.5 and plan to bi-amp them with MyRefs FE for HF+MF combo and Audiosector LM4780 parallel kit for LF. No extreme listening levels are planned.
Now the questions...
Could someone recommend me a good DAC for MyRefs FE + ZDT3.5's? I am looking at the NOS DDDAC1794 at the moment. Would it be overkill or just right match for my speakers and amp? Or I should consider something else...?
The questions are due to the lack of personal experience with good quality setup. I just started assembling mine from scratch. The most probable source of music is PC.
Any ideas/suggestions are welcome!
Thank you!
Oleg
My suggestion is to first try driving the entire speaker with the FE alone. I think you will be pleasantly surprised how it handles three way speakers. Some FE builders have had better results by adding a sub (seldom needed) to small/medium speakers rather than using multiple amps.
Dario's Mini 2496 mod is a high standard for both entry level and much higher systems. It is not very expensive and outperforms DACs costing much more. I'm very impressed with the new Subbu/Jean Paul V3 but that GB has completed. Though not official. there should be a subsequent version with a few upgrades and I2s input. I'd suggest holding off on any investment for a high dollar DAC till that picture becomes a bit more clear.
Dario's Mini 2496 mod is a high standard for both entry level and much higher systems. It is not very expensive and outperforms DACs costing much more. I'm very impressed with the new Subbu/Jean Paul V3 but that GB has completed. Though not official. there should be a subsequent version with a few upgrades and I2s input. I'd suggest holding off on any investment for a high dollar DAC till that picture becomes a bit more clear.
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Thanks a lot for your suggestions Bob M.!
I am not much into tweaking something but rather build once and enjoy. I will have a closer look at Subbu DAC. I hope the group buy will start soon if I would decide to try it. I want quality sound already now🙂
Oleg
I am not much into tweaking something but rather build once and enjoy. I will have a closer look at Subbu DAC. I hope the group buy will start soon if I would decide to try it. I want quality sound already now🙂
Oleg
Hi Oleg,
I would quote Bob on this
Just to be sure... those ZDT3.5 are a 4 ohm design, did you buy 21V secondaries transformers for the FEs?
As Bob already suggested the Mini 2496 is a good low cost choice.
A fine alternative that already includes USB support via XMOS chip (one of the best in such role) is the XMOS AK4399 dac, search on ebay for 'finished dac ak4399 xmos'.
BTW the DAC I'm using now, unmodded, is a really good one, the only one that clearly bettered my Sony ES SACD player, the Arcam iRDAC (different from the older RDAC).
Thanks a lot Dario!
I tend to convert price of a kit into potential quality. Basically it should not be so trivial. Assuming the cost of the DACs that you and Bob are suggesting I could try more options before settling on something.
As for the transformer for MyRefs I've ordered custom made 250 VA transformer with two primary taps (thanks AndrewT for suggestion): for 4x20VAC and 4x24VAC output while keeping the power rating. So with a single switch I can adjust for a speaker impedance.
Oleg
I tend to convert price of a kit into potential quality. Basically it should not be so trivial. Assuming the cost of the DACs that you and Bob are suggesting I could try more options before settling on something.
As for the transformer for MyRefs I've ordered custom made 250 VA transformer with two primary taps (thanks AndrewT for suggestion): for 4x20VAC and 4x24VAC output while keeping the power rating. So with a single switch I can adjust for a speaker impedance.
Oleg
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Well the amp works!
Gotta say it works very nice, just need to install the power switch and some cleaning up of the internal and external and i am done.
As promised some pics
Gotta say it works very nice, just need to install the power switch and some cleaning up of the internal and external and i am done.
As promised some pics
Good job! 🙂
Can you share what was the problem? Transformer's wires?
Nice build, keep us informed with your impressions on audio performance.