I can't understand what you're talking about; the Silmics in C6, C11 are 35V rated and they operate with +- 12V...
Regarding the Silmic in C9, not used in the GB since we're going to use BGs, the 35V rating is not a problem, there's people here in Italy that in such position uses 6,3V OSCONs...
Sorry, Uriah, but I don't have a pic of the R3 heatsink. All I can tell you is it fits pretty well one way, with just a bit of easy trimming, and will not fit at all the other way due to those two lytic caps. The back of the resitor (the heatsink side) faces the center of the board.
I used 22v xformer in my amps because I wanted 4 ohm load stability. They still play plenty loud with 8 ohm speakers, 88-89 db efficient. I have not yet maxed out the volume (clipped or otherwise limited), but then I have somewhat of a filter on the lowest frequencies due to my smaller input cap. That was my intent all along, and those beautiful simulations a few pages back confirmed what I hear. Perhaps there is more "music power" available when lows are limited.
Peace,
Tom E
I used 22v xformer in my amps because I wanted 4 ohm load stability. They still play plenty loud with 8 ohm speakers, 88-89 db efficient. I have not yet maxed out the volume (clipped or otherwise limited), but then I have somewhat of a filter on the lowest frequencies due to my smaller input cap. That was my intent all along, and those beautiful simulations a few pages back confirmed what I hear. Perhaps there is more "music power" available when lows are limited.
Peace,
Tom E
Obviously the reccomended values I've reportet are for an 8 Ohm load, for 4 Ohm loads a 2x22V is more stable, as reported by Tom.
Impatient Enthusiast
Sorry for being so impatient, I can't help it.
How did it go with the trial population of the boards Uriah?
Any news?
BTW you mentioned a separate build thread, where is it please?
I think I found it... just checking.
Is it a good idea to start a beginners build thread for posting really basic questions? This would rely on some of the experts being generous enough to check the thread from time to time.
Does anyone have a good suggestion for an input selector which would work OK with the My RefC and Lightspeed combination? I could be tempted to build an integrated set up...
Hope all are well!
Bill
Sorry for being so impatient, I can't help it.
How did it go with the trial population of the boards Uriah?
Any news?
BTW you mentioned a separate build thread, where is it please?
I think I found it... just checking.
Is it a good idea to start a beginners build thread for posting really basic questions? This would rely on some of the experts being generous enough to check the thread from time to time.
Does anyone have a good suggestion for an input selector which would work OK with the My RefC and Lightspeed combination? I could be tempted to build an integrated set up...
Hope all are well!
Bill
pics
Bill,
Dont sweat building it yet. Really, its very very simple. Yes there are several of us that will help you build. You wont be in the dark. I would prefer to use the same build thread because it decreases the number of repeat questions.
Everyone,
Sonidos and I are kitting this weekend. I have a few parts that are slooooowly making it to my house. Apparently the distributor has several warehouses and is combining my order from 3 different locations. So, I will have to kit up those last parts after I receive them.
Does that mean I will be shipping later than 22-26? Absolutely. I figure two weeks from now. I dont figure any later than that. They told me Monday it would be a total of 10 days to get the last 4 parts.
TOROIDS
I will take the toroids off of the website this evening as I am placing the order this evening. If you want 160VA 22VAC dual secondary toroids proven to work well with this amp please please order. I am not ordering extras and if you are not in by this evening its done on the toroids.
Pics here
Picasa Web Albums - Uriah - Ultimate MyREF
Bill,
Dont sweat building it yet. Really, its very very simple. Yes there are several of us that will help you build. You wont be in the dark. I would prefer to use the same build thread because it decreases the number of repeat questions.
Everyone,
Sonidos and I are kitting this weekend. I have a few parts that are slooooowly making it to my house. Apparently the distributor has several warehouses and is combining my order from 3 different locations. So, I will have to kit up those last parts after I receive them.
Does that mean I will be shipping later than 22-26? Absolutely. I figure two weeks from now. I dont figure any later than that. They told me Monday it would be a total of 10 days to get the last 4 parts.
TOROIDS
I will take the toroids off of the website this evening as I am placing the order this evening. If you want 160VA 22VAC dual secondary toroids proven to work well with this amp please please order. I am not ordering extras and if you are not in by this evening its done on the toroids.
Pics here
Picasa Web Albums - Uriah - Ultimate MyREF
OH
Some really cool news!
BillP has some LM318H opamps. Now, opamp rolling is NOT advised in this build however Bill is suggesting we try the same opamp in a metal package. I have heard that this generally provides better sound and am excited to try them out. He is sending 8, or has 8, I forget. But anyway I will keep two and send the rest on to the other testers.
As for how the build went it was easy but I forgot how long it takes to populate this thing and solder it up. Wish I had a big solder pot to just dip it in
One thing that really helped, especially with the opamp, LM3886 and several leads that are really close together on the board is Flux. Rosin Flux. Awesome stuff that make soldering really easy. Also I started using it on the LDR mount and balance boards and recommend it for that as well as soldering times are significantly reduced and the LDRs dont like much heat. I was using rosin core solder and even using the flux still helps a lot.
HOWEVER I do need to get some flux remover as you can see on the pic of the bottom of the PCB.
Uriah
Some really cool news!
BillP has some LM318H opamps. Now, opamp rolling is NOT advised in this build however Bill is suggesting we try the same opamp in a metal package. I have heard that this generally provides better sound and am excited to try them out. He is sending 8, or has 8, I forget. But anyway I will keep two and send the rest on to the other testers.
As for how the build went it was easy but I forgot how long it takes to populate this thing and solder it up. Wish I had a big solder pot to just dip it in
One thing that really helped, especially with the opamp, LM3886 and several leads that are really close together on the board is Flux. Rosin Flux. Awesome stuff that make soldering really easy. Also I started using it on the LDR mount and balance boards and recommend it for that as well as soldering times are significantly reduced and the LDRs dont like much heat. I was using rosin core solder and even using the flux still helps a lot.
HOWEVER I do need to get some flux remover as you can see on the pic of the bottom of the PCB.
Uriah
The new PCB solder mask is so SEXY!
Ouch!, it seems that some parts don't fit well...
the two MKS4 seems 10mm lead spacing and not the MKP4 7,5mm lead spacing I've specified (perfect fit, see attachment).
Uriah, tell me that R12 is a Shinkoh and that for this position we have PRPs because R12 is one of the most important resistors in the signal path.
Most of the PRPs that doesn't fit are out of the signal path, any good metalfilm resistor would have been as good there and it would fit too...
If someone would like to save those PRPs for other projects (I will do) these are the standard metal film resistors (0,25W) to use/order:
R14 470 1W
R15 75K
R16 75K
R19 10K
R20 47K
R21 220K
R22 8K2
R23 6K8 0,5W
Same goes for C16 and C14 if anybody cares.
Attachments
Last edited:
Yep, its a shinkoh. I am going to compare prp and shinkoh there. I am taking every care to make sure things are done right. What we give up in that search is maybe a bit of perfection in fit as you note. Check out that Black Gate and Obbligatto! The things are both massive.
The two WIMA are an odd fit but do fit with bending one lead a bit. I used the part number specified by either you or Tom on those but its no big deal as they dont get in the way.
If this amp sounds as incredible as you two are making me think I will probably redo the board to fit an ultimate BOM rather than such a standard BOM. I think if I do that I will also open discussion to any other improvements so we can make our own version of what an 'evolution' of this circuit might be. See how it goes Would be cool to stick a few LDRs in the signal path as replacements to existing resistors and see the changes as well.
The two WIMA are an odd fit but do fit with bending one lead a bit. I used the part number specified by either you or Tom on those but its no big deal as they dont get in the way.
If this amp sounds as incredible as you two are making me think I will probably redo the board to fit an ultimate BOM rather than such a standard BOM. I think if I do that I will also open discussion to any other improvements so we can make our own version of what an 'evolution' of this circuit might be. See how it goes
Would be cool to stick a few LDRs in the signal path as replacements to existing resistors and see the changes as well.
The Mouser code 505-MKP4.1/250/10 is correct, I've ordered it two times and you can see the actual ordered parts in the photo of my previous post...
Actually is Tom that described it as the best thing after sliced bread...
What I state is that with selected parts this amp can perform much better than with standard ones.
Some adjustment to the board would be great, particularly regarding elcos C1, C2, C9, C3, C8 and replacement of the LM318 PS with a better one but the board couldn't be easily redrawn, since stability and performance are tightly related to the PCB design.
A little bending here, a little squeeze there...
That Obbligato is enormous, at least twice the size of any other cap I tried there. If leads do not have insulation, wrap them with teflon plumber's tape. Enclosure will now need to be a bit bigger. Those PS caps also look pretty tall!
The Blackgate looks good under the board, but now the standoffs will be longer.
I don't know why so many PRP's don't fit. They look kind of big. Did you get 1/2 watt instead of 1/4 watt? No harm, other than size, I guess. All of mine except one or two (R14 or R23-- can't remember which, maybe both) fit in the space with room to spare, no oddly bent leads. It would probably cause little sonic effect to use other, smaller size resistors in those spots. In signal path, PRP's are really nice.
I could not find the WIMA caps with 7.5mm lead spacing either. Using 10mm caused only minor difficulty. 7.5mm is a totally weird size.
Did you install a socket for the opamp?
Now that I've hyped this thing so much, I guess my butt is really on the line! Uriah, you must be going nuts, looking at half an amp after all this work, wondering how it will sound. I'm getting a little anxious myself, wondering what everyone will think.
Peace,
Tom E
That Obbligato is enormous, at least twice the size of any other cap I tried there. If leads do not have insulation, wrap them with teflon plumber's tape. Enclosure will now need to be a bit bigger. Those PS caps also look pretty tall!
The Blackgate looks good under the board, but now the standoffs will be longer.
I don't know why so many PRP's don't fit. They look kind of big. Did you get 1/2 watt instead of 1/4 watt? No harm, other than size, I guess. All of mine except one or two (R14 or R23-- can't remember which, maybe both) fit in the space with room to spare, no oddly bent leads. It would probably cause little sonic effect to use other, smaller size resistors in those spots. In signal path, PRP's are really nice.
I could not find the WIMA caps with 7.5mm lead spacing either. Using 10mm caused only minor difficulty. 7.5mm is a totally weird size.
Did you install a socket for the opamp?
Now that I've hyped this thing so much, I guess my butt is really on the line! Uriah, you must be going nuts, looking at half an amp after all this work, wondering how it will sound. I'm getting a little anxious myself, wondering what everyone will think.
Peace,
Tom E
Thanks Tom. No, no problems yet but I'm doing inventory on parts on hand versus parts to be aquired and seeing what I may need to buy for stuffing extra boards.
Here it is a Mouser/Digikey BOM for those interested in stuffing extra boards.
This BOM includes all the upgrades of this group buy except PRPs, BlackGates (not available from Mouser/Digikey) and indicates standard parts for non critical positions.
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