Hi Tea,
I'm planning to put the phono pcb together during my holiday break and have a few questions concerning the minikit. In the kit that I got there are 4 PRP resistors, 2 - 47K and 2 - 6.75K, what resistor positions are they for, I see R1, R14 are 47K on the BOM, but none are for 6.75K. Also in the kit I got a 6 green, 8 yellow, and 2 red LEDs. In the build guide is says to measure for 2 quartets at 7.75v and two triplets at 5.8v., in the BOM it mentions D1x - D4x for the regulator section and D1 - D4 for RIAA section. Do I need to measure these LEDs, or are they already selected to be in tolerance so I can just put them in the board.
Thanks,
Paul
I'm planning to put the phono pcb together during my holiday break and have a few questions concerning the minikit. In the kit that I got there are 4 PRP resistors, 2 - 47K and 2 - 6.75K, what resistor positions are they for, I see R1, R14 are 47K on the BOM, but none are for 6.75K. Also in the kit I got a 6 green, 8 yellow, and 2 red LEDs. In the build guide is says to measure for 2 quartets at 7.75v and two triplets at 5.8v., in the BOM it mentions D1x - D4x for the regulator section and D1 - D4 for RIAA section. Do I need to measure these LEDs, or are they already selected to be in tolerance so I can just put them in the board.
Thanks,
Paul
This is from the Mini-kit blog.
D1-D4x D1x any red, D2x-D4x two yellow one green. (5.83)
D1-D4 - Riaa section, two yellow, two green (7.80v)
Correct on the resistors. Use R5 or R6 position.
R14 is what is meant to be covered with this. Use R1 with favorite flavor resistor.
Unless MC . then save that for the better value IMO
D1-D4x D1x any red, D2x-D4x two yellow one green. (5.83)
D1-D4 - Riaa section, two yellow, two green (7.80v)
Correct on the resistors. Use R5 or R6 position.
R14 is what is meant to be covered with this. Use R1 with favorite flavor resistor.
Unless MC . then save that for the better value IMO
Hi Guys,
One more question about the PSU this time. There are two RD links shown on the board, but no mention of them in the BOM in the guide. The pic of the completed PSU in the beginning of the thread shows two 5W1RJ power resistors. Am I right in assuming that these are 1R, 5W wire wound power resistors ?
Thanks
Paul
One more question about the PSU this time. There are two RD links shown on the board, but no mention of them in the BOM in the guide. The pic of the completed PSU in the beginning of the thread shows two 5W1RJ power resistors. Am I right in assuming that these are 1R, 5W wire wound power resistors ?
Thanks
Paul
The guide and FSP board preceded the RAW PSU board addition. After the first run enough members suggested they would be content with the example raw supply in the guide and a board for that would be welcome. The only addition to the schematic is the RD/Link break between the bridge rectifiers and the smoothing capacitor for each channel.
Its there because in enough situations transformers proved stronger than labeled. At least on most mains for the limited current draw of the FSP.
If the raw DC output does not exceed 50V with just a wire jumper you may keep it or use 1 Ohm/5W as mild EMI filter. If higher, use 20 Ohm/5W as a voltage drop/filter. To know exactly what will happen for DC out before connecting the real load i.e. the phono, you can load it with 470 Ohm/10W as a test. Evaluate and decide for RD/Link in safety.
In general, 50VA or bigger American made toroids on domestic mains nearing 120VAC will be about 10% healthier for secondary voltage than what printed on the label in the context of FSP loaded use.
Its there because in enough situations transformers proved stronger than labeled. At least on most mains for the limited current draw of the FSP.
If the raw DC output does not exceed 50V with just a wire jumper you may keep it or use 1 Ohm/5W as mild EMI filter. If higher, use 20 Ohm/5W as a voltage drop/filter. To know exactly what will happen for DC out before connecting the real load i.e. the phono, you can load it with 470 Ohm/10W as a test. Evaluate and decide for RD/Link in safety.
In general, 50VA or bigger American made toroids on domestic mains nearing 120VAC will be about 10% healthier for secondary voltage than what printed on the label in the context of FSP loaded use.
What is printed on the lable is the manufcaturer telling you the output voltage when the mains voltage is set to the rated primary voltage and the load on the secondary draws rated secondary current.
It is not about "healthier", nor is it about "stronger than labeled"
If one has a 115:36Vac 12% regulation transformer then the unloaded output voltage is given by: Vout = Mains supply voltage / Rated primary voltage * rated secondary voltage * 1+regulation.
i.e. that 36Vac transformer when fed with 120Vac mains has an unloaded output voltage of 120/115*36*(1+0.12) = 42.07Vac
That is completely normal and completely predictable.
Output voltage
It is not about "healthier", nor is it about "stronger than labeled"
If one has a 115:36Vac 12% regulation transformer then the unloaded output voltage is given by: Vout = Mains supply voltage / Rated primary voltage * rated secondary voltage * 1+regulation.
i.e. that 36Vac transformer when fed with 120Vac mains has an unloaded output voltage of 120/115*36*(1+0.12) = 42.07Vac
That is completely normal and completely predictable.
Output voltage
Its a key phrase from my previous post reminding that biggish transformers when loaded by FSP will be near unloaded state. That is why I talked about 10% overshoot. From then on your regulation post explained the why in detail and its right. Because 33VAC nominal is not common for off the shelf models when 32 or 34VAC models are available, better buy those to end up in ballpark when talking 100VA total in double mono or 100VA single core with twin isolated secondaries. 36VAC secondary should be taken as a measured value when loaded with FSP on typical mains, not as a label value. RD/Link is nonetheless always there to tune out any overshoot or just jumper it when in target, even use it to create a mild EMI filter with very little drop. So no real worries.
The GB for the Salas boards is open for payment up until 11:59PM EST 1/24/2016.
Payment is via PayPal invoice only. You will need to send me your paypal email via private message for me to start this process. Then I will invoice the parts you requested from the spreadsheet. If you reply to this email - cut out some of the existing text, otherwise the message is too big.
Customs forms
DO NOT ask for me to fudge up a customs form with really low amount. These are based on areasonable wholesale price.
Shipping
In general boards are a set costs, and mini kits are built into the shipping costs and larger full kits are 10.00-12 to ship. Starting price for shipping is 8.00 for just a small board and can rise from there.
The boards will ship around 2-3 weeks after the GB closes typically. The boards need to be ordered, I don't have them on hand.
Folded Simple Phono Preamp
Per board cost is $52.00
Link for first post for build guide
http://www.diyaudio.com/forums/grou...-folded-simplistic-phono-pcb.html#post3615620
RAW Supply details -Use before RIAA board as pre power supply.
$15.00 for PCB
MiniKit BOM section. This links goes to full details of all the parts included in the kits and there respective positions on the board.
http://www.diyaudio.com/forums/blogs/tea-bag/741-salas-board-minikits-full-kits.html
Payment is via PayPal invoice only. You will need to send me your paypal email via private message for me to start this process. Then I will invoice the parts you requested from the spreadsheet. If you reply to this email - cut out some of the existing text, otherwise the message is too big.
Customs forms
DO NOT ask for me to fudge up a customs form with really low amount. These are based on areasonable wholesale price.
Shipping
In general boards are a set costs, and mini kits are built into the shipping costs and larger full kits are 10.00-12 to ship. Starting price for shipping is 8.00 for just a small board and can rise from there.
The boards will ship around 2-3 weeks after the GB closes typically. The boards need to be ordered, I don't have them on hand.
Folded Simple Phono Preamp
Per board cost is $52.00
Link for first post for build guide
http://www.diyaudio.com/forums/grou...-folded-simplistic-phono-pcb.html#post3615620
RAW Supply details -Use before RIAA board as pre power supply.
$15.00 for PCB
MiniKit BOM section. This links goes to full details of all the parts included in the kits and there respective positions on the board.
http://www.diyaudio.com/forums/blogs/tea-bag/741-salas-board-minikits-full-kits.html
Hi Everyone,
I tried firing up my RIAA build today and had an issue on one channel that I'm hoping someone can offer some guidance on. I set it up for a 4 mV MM cart so I followed the notes and left Q2, R3 unpopulated and used 91R - R2, 5.6K- R13, 1.8K -R4, 100nF- C3
PSU up and running no problem, 115 vac in 48 vdc out
Good side RIAA started no problem could only get 33.2 vdc across + rail to gnd before VR2X ran out of adjustment, TP1 - TP2 was 3.5 vdc, and all LED lit as described in guide. Adjusting VR1X made no difference.
Problem came with starting up other channel, R1X began to overheat and smoke, D2x, D3X, D4X did not light. I pulled power immediately and did not notice if other diodes lit up. I don't see a schematic of the regulator section in the guide so I'm a bit lost on what to look for and would appreciate any help.
Thanks,
Paul
I tried firing up my RIAA build today and had an issue on one channel that I'm hoping someone can offer some guidance on. I set it up for a 4 mV MM cart so I followed the notes and left Q2, R3 unpopulated and used 91R - R2, 5.6K- R13, 1.8K -R4, 100nF- C3
PSU up and running no problem, 115 vac in 48 vdc out
Good side RIAA started no problem could only get 33.2 vdc across + rail to gnd before VR2X ran out of adjustment, TP1 - TP2 was 3.5 vdc, and all LED lit as described in guide. Adjusting VR1X made no difference.
Problem came with starting up other channel, R1X began to overheat and smoke, D2x, D3X, D4X did not light. I pulled power immediately and did not notice if other diodes lit up. I don't see a schematic of the regulator section in the guide so I'm a bit lost on what to look for and would appreciate any help.
Thanks,
Paul
Attachments
The regulator section schematic is in the last page of the guide. Use little higher value R3x in the good channel for more Rail+ range
To the bad channel now...
Check the health and correct orientation of D2X D3X D4X with a DMM that can light up an LED when its selector is in diode check mode. No need to remove them for that check
Also check across Q2x for Ohms so to see its not shorted. It should show many Ohms in the range of 70-120
If the above are good change Q1X MOSFET along R1x. It could be gate broken by static and caused the failure
Last but not least make sure you did not accidentally connect the raw PSU in reverse polarity to the DC IN connector of the bad FSP channel
For more debugging come to the main thread "Simplistic NJFET RIAA"
To the bad channel now...
Check the health and correct orientation of D2X D3X D4X with a DMM that can light up an LED when its selector is in diode check mode. No need to remove them for that check
Also check across Q2x for Ohms so to see its not shorted. It should show many Ohms in the range of 70-120
If the above are good change Q1X MOSFET along R1x. It could be gate broken by static and caused the failure
Last but not least make sure you did not accidentally connect the raw PSU in reverse polarity to the DC IN connector of the bad FSP channel
For more debugging come to the main thread "Simplistic NJFET RIAA"