thatmetalman Posted January 6 Posted January 6 On 06/01/2025 at 12:24 AM, Leinster Lad said: Hi Tim and happy new year to you ! Be great to hear the results of your bench testing. R10 47K must be from an earlier version of your power supply. Expand Ah, yes. An older version. The 47K was to accommodate the mute transistors if I recall correctly. It was removed for the reed relays. Updated supply below. 2
Leinster Lad Posted January 6 Posted January 6 Hi Tim, just wondering if the main schematic will be posted soon ? ( relay and MKP version )
thatmetalman Posted January 9 Posted January 9 (edited) On 06/01/2025 at 8:17 AM, Leinster Lad said: Hi Tim, just wondering if the main schematic will be posted soon ? ( relay and MKP version ) Expand Hi David. Hot off the press from this morning. MKP or Electro options on-board for signal path caps. Happy to take feedback. One aspect I'm not thrilled about is the copper track length to accommodate the MKPs and their optional electros. Perhaps it's a non event? Otherwise, I'm happy that everything could be accommodated. I need to check that the 4N28 can manage the relay current (Tilbrook encouraged me to check this!). Cheers, Tim [edit] just noticed a schematic error with C55 - non polarity cap to be inserted. Edited January 9 by thatmetalman 1
Leinster Lad Posted January 9 Posted January 9 On 09/01/2025 at 1:11 AM, thatmetalman said: I need to check that the 4N28 can manage the relay current Expand Great work Tim. Must be getting close to ordering the boards ! Not following you with regards to the 4N28 handling relay current ? it only switches the bases of Q1 and Q2 right ? All mute power comes from IC3, or am I missing something ? 1
Leinster Lad Posted January 9 Posted January 9 Also, one for the experts. Socket the NE5534n's or solder ??? 1
MarcAL Posted January 9 Posted January 9 On 09/01/2025 at 5:49 AM, Leinster Lad said: Also, one for the experts. Socket the NE5534n's or solder ??? Expand Gold plated sockets for me.
thatmetalman Posted January 9 Posted January 9 On 09/01/2025 at 4:02 AM, Leinster Lad said: Great work Tim. Must be getting close to ordering the boards ! Not following you with regards to the 4N28 handling relay current ? it only switches the bases of Q1 and Q2 right ? All mute power comes from IC3, or am I missing something ? Expand I just checked my notes from the last session with David, and all I had was "Check 4N28 current". Yes you're correct that the 7815 provides the current; IC1 turns on Q1-Q4. I'll ask David again in case I misunderstood. Sockets for the 5534s? 100% yes. Gold plated machined pin sockets. Still very cheap to buy, and a no brainer for me. The footprints accommodate those sockets and were selected on purpose, btw T 2
bob_m_54 Posted January 9 Posted January 9 From the diagram: Q3 - Supplies GND to the LED in IC1 4N28 Optocoupler, and switches it on. IC1 - switches Q1 & Q2 enabling supply to the two low noise + & - rails from the bridge rectifiers. Q4 - (BC558) Supplies +15V to the two relays K54 & K52. total current 65mA BC558 is supposed to handle 100mA constant, and 200mA max peak. Hope that helps..
thatmetalman Posted January 9 Posted January 9 On 09/01/2025 at 11:21 PM, bob_m_54 said: From the diagram: Q3 - Supplies GND to the LED in IC1 4N28 Optocoupler, and switches it on. IC1 - switches Q1 & Q2 enabling supply to the two low noise + & - rails from the bridge rectifiers. Q4 - (BC558) Supplies +15V to the two relays K54 & K52. total current 65mA BC558 is supposed to handle 100mA constant, and 200mA max peak. Hope that helps.. Expand Hi Bob. Thanks for the observation, it's appreciated. Cheers, Tim 1
thatmetalman Posted January 14 Posted January 14 Hi folks. I've emailed the final changes to David for his comment. Otherwise I'm ready to order the boards after making some minor changes/fixes. Constructors can choose MKP or electros in signal path - both footprints are available. Optional 470u on the op-amp outs is provided in lieu of the original 47u caps per Doug Self comments. Although David stated to me that 470u wasn't necessary, I've stuck with that value purely off the back of Doug Self testing. No reason why a smaller 47u could not be installed instead. 2
Leinster Lad Posted January 14 Posted January 14 Great news Tim. I am excited to get a set of your boards ! I did start making a BOM with Mouser. I have done all the semi's on the main board. And I have used Onsemi as much as possible. There were a couple of items that were not available from them, so substituted Texas Instruments. Resistors i'll try and use all Dale's, but I will have to wait for the boards to measure the pin pitch etc. I want this build to be perfect ! Same with the caps. I need to get the correct sizes ( pin pitch ) etc Have you created any BOM's yet ? and where did you find the MKP's ? ( part numbers ? )
Leinster Lad Posted January 14 Posted January 14 (edited) Oh, will you be creating and selling the boards ? Are the other boards ( switch, Vu, phono ) boards ready to go or not yet ? I have 2 of these amps and seeing how much work you have put into this 2025 "blueprint" edition, I am very tempted to do both. So that will be 2 sets of boards for me Edited January 14 by Leinster Lad
thatmetalman Posted January 15 Posted January 15 On 14/01/2025 at 4:26 AM, Leinster Lad said: Oh, will you be creating and selling the boards ? Are the other boards ( switch, Vu, phono ) boards ready to go or not yet ? I have 2 of these amps and seeing how much work you have put into this 2025 "blueprint" edition, I am very tempted to do both. So that will be 2 sets of boards for me Expand Hi David. BOM is done and includes hard to get parts as Mouser part numbers. DM me and I'll send you my email address - I can then send the BOM to you. Yes, 2 boards/sets for you Yes I will be creating and selling the boards. Got an email from DT last night saying that he has new calculations for the RIAA, so some minor changes to the MC/MM boards. Otherwise they are done and ready to go. The VU boards are also done and ready to go. As an aside, I liked the original author post's MM board impedance selector via DIP and intended to incorporate that idea. However, DT suggests that it isn't necessary based on his experience of not finding many cartridges that warrant change. That could be revisited another time perhaps, but for now no change on that front. Tim 1
MarcAL Posted January 16 Posted January 16 On 14/01/2025 at 3:18 AM, thatmetalman said: Hi folks. I've emailed the final changes to David for his comment. Otherwise I'm ready to order the boards after making some minor changes/fixes. Constructors can choose MKP or electros in signal path - both footprints are available. Optional 470u on the op-amp outs is provided in lieu of the original 47u caps per Doug Self comments. Although David stated to me that 470u wasn't necessary, I've stuck with that value purely off the back of Doug Self testing. No reason why a smaller 47u could not be installed instead. Expand This is truly excellent work Tim. I would be interested in purchasing a full set of these boards once they become available. 1
thatmetalman Posted February 24 Posted February 24 Hi guys. The main board layout is finally complete after re-doing the PSU layout. I was never 100% satisfied with it, so a few more late nights. Resulting in shorter track length, etc. Also, all clean +-15v tracks are now isolated back to their respective main filter cap, and this includes the tracks that feed to moving coil 10v rails as well as the LED meters (i.e. each satellite board has its own line). I relented and installed SMD bypass caps for the large filter caps in the power supply only. The through hole versions were too big and were forcing long tracks and layout challenges. I've used the largest footprints suitable for hand soldering, so for those of you previously relieved about no SMD, no need to fret. The SMDs are no more challenging than the 0.1uF monos (which remain radial for the underside). If my old eyes and shaky hands can manage it, you can. I've sourced 2u2 and 47u MKPs for each op amp in/out, and will share that stuff soon. Prices are a balance between quality (Kemet and Wima). Board footprints accommodate electros or MKPs, whatever your budget allows. Some eye candy also added (ETI logo for nostalgia) along with some 'easter eggs' for fun. I'm now working through 300+ DRC warnings, the majority of which are non-issues relating to footprint silkscreen stuff (promise!). I haven't added a MKP device for the unity gain inverting amplifier section (Mode - Stereo, etc.). The MM and MC boards will follow, David is busy atm so won't have time to discuss for a few weeks at least. The LED boards are done. I received samples of translucent perspex as well as rubber to test in the front panel slots. This will eliminate LED alignment challenges. Sub boards also done. Tim
MarcAL Posted February 24 Posted February 24 Again this is truly excellent work Tim. Bravo. Can't wait till the boards are available. Please let us know later on what parts you may have available if possible. 1
thatmetalman Posted February 24 Posted February 24 Thanks guys. While I think about it, as I’ve been checking part numbers I’ve noticed that Digikey are significantly cheaper than Mouser. I order from Mouser and I love their service, but Digikey are killing them on price for this design. Silicon Chip magazine staff seem to order most of their kit parts from Digikey, so I plan on giving DK a go. I am methodically adding Digikey parts numbers to board footprints for the BOM for this reason but will use Dave’s work for Mouser parts too for choice. As an aside I prefer to support Altronics as an Aussie business, and include their part numbers also where possible. Also, Alps pots and original UK Lorlin MBB switches. Having trouble finding detent pots for volume and centre detent balance but I did order some Alps pots from Japan (no detents). Switches are available from a bloke in Perth. Still working towards a complete kit for newbies, and sets of boards for those with existing units for refurb. Chassis suppliers are plentiful in China, Australia thankfully still has suppliers but haven’t sent drawings for quote yet. Tim 1 1
thatmetalman Posted February 28 Posted February 28 (edited) Morning everyone. Days in front of the computer to fill in part numbers for the BOM. A big thank you to Dave for his work on the same. I've incorporated some of Dave's BOM material into the main BOM. Some comments: Vishay CMF series resistors have been added to the preamp section only. The PSU resistors IMO don't need resistors of this high spec (and cost), however, if someone wants to set me straight on that front, I'll add them in. Otherwise use 0.5w 1% metal film from any supplier. A massive thanks to Dave for his long hours work on the Vishay devices, and cross-checks from schematic to BOM especially. That's toe-curling stuff. Here are the data sheets/searches I used to settle on the CMF series (which are axial devices) - these are slowly being retired in favour of SMD, so get in and order if you want to go down this path: All Vishay series resistors PDF Vishay CMF series landing page with additional data and information Vishay CMF datasheet PDF Mouser advanced search link for all IN STOCK Vishay CMF series resistors for those who want to dive deeper into availability and value options Digikey same as above Some E96 series values are unavailable. Where this is the case I've added the next closest value as a second or third option in the BOM. Or, reference Dave's BOM for the alternative Vishay series (Dave can post if he chooses). Bulk order quantities are obviously available, and the savings in some cases are significant, ergo; I can place orders for all values (or nearest where applicable - with the caveat of nearest being untested, so use odd values at your own risk) - please tell me if you want to jump on board. Front panel potentiometers and switches are not on the BOM. So, now a crossroads. I've spent way too long on the main board development. It's as perfect as it needs to be (perfection is an albatross!). That said, I want to test the PSU and the mute circuit parts first before ordering boards, even though it's tempting to "confidently" place orders! So this will delay things. I could order boards and supply them to interested folks, with an obvious disclaimer of possible mods (tracks, etc.) if something isn't right. Happy to take feedback including requests, etc. prior to board orders. DM or email me if you prefer to take it off thread. Cheers, Tim Edited February 28 by thatmetalman image size incorrect 1
Leinster Lad Posted February 28 Posted February 28 Looks like we are getting close Tim !! For those interested, the Mouser BOM that I created is attached. Please let me or Tim know if you find any errors. Mouser BOM.docxFetching info... 1
MarcAL Posted February 28 Posted February 28 On 28/02/2025 at 4:41 AM, Leinster Lad said: Looks like we are getting close Tim !! For those interested, the Mouser BOM that I created is attached. Please let me or Tim know if you find any errors. Mouser BOM.docx 23.91 kB · 0 downloads Expand I shall check this out over the weekend. Thanks David and Tim.
thatmetalman Posted February 28 Posted February 28 (edited) I've spent a few hours looking for the right Alps pots with relevant detents. Alps list everything on their data sheets, but try finding the right combos. RV1 1 100K C dual logarithmic MASTER RV2 1 10K A dual linear BALANCE RV3 1 10k C dual logarithmic MONITOR I'm not going to pursue this much longer, they're difficult to find in the exact configs. If anyone's interested, here's Mouser's range in the RK71 series, a filtered search, and the Alps datasheet for that series. If someone wants to research some more and track them down, that'd be great. I find that audio precision pots are a rabbit hole. Any leads, folks? Lorlin CK series PCB mount rotary switches are "somewhat" easier to find. Datasheet attached. All must be MAKE BEFORE BREAK, FYI. I found a guy in Perth who sells them but I cannot for the life of me find the order or emails. But it seems that Element 14 and others do stock variations. Here are the Lorlin part numbers. Please check before ordering, I make mistakes. Lorlin CK1056 or CK1061 SW1 1 2 Pole 3 Pos LOW LEVEL INPUT Lorlin CK1056 or CK1061 SW2 1 2 Pole 4 Position HIGH LEVEL INPUT Lorlin CK1056 or CK1061 SW3 1 3 Pole 4 Pos TAPE INPUT SELECT Lorlin CK1056 or CK1061 SW4 1 2 Pole 3 Pos TAPE MONITOR SELECT Lorlin CK1056 or CK1061 SW5 1 3 Pole 4 Pos MODE SWITCH Lorlin CK1062 or CK1057 SW6 1 4 Pole 2 Pos POWER SWITCH Cheers. CK-ROTARY-Nov-2020-1.pdfFetching info... Edited February 28 by thatmetalman left out power switch 1
thatmetalman Posted March 18 Posted March 18 All, Conscious of the fact that 3 weeks has elapsed. In the meantime I picked up some casual work behind a shop counter which has taken me away from this. It's good because it gets me out of the house! Then add a laundry reno. So, apologies (again). The Mouser order arrived 2 weeks back. The 30uF MKP Wima caps on first look appeared to be too high. I just assembled the original case, and the caps fit like a glove with no room to spare. That's working with 2 x M3 nuts as spacers. There needs to be enough space to accommodate the SMD caps and monos as well as the 7815 mounting hardware. But it is tight for those of us retro-fitting! The power supply I tested 2 weeks back and all seems okay there. I've breadboarded the mute delay circuit and will test the BD681/682 soon to ensure they're ok to switch the supply rails under load. On paper they're fine. I don't expect a problem. Also will test the reed relays in circuit. With all this confirmed I'll test the different MKPs. I ordered Wima, TDK and Kemet but I don't expect a huge difference. As I said a few weeks ago, I could order the boards with a degree of confidence but I don't want to be caught out with track mods if something isn't right. Hope everyone's well. Cheers, Tim 1
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