Dario,I can buy them for those interested.
A costly alternative would be the BG F linked by Bob.
Also the BG F linked by Bob should be a nice choice, probably excellent also for C1/C2.
If someone is willing to organize a GB for them I'll be in for 4 of them
.
I hope you don't mind me using your thread for this. I could start my own, but this is a question of parts for the build, so I was hoping this would be OK.
OK all you FE builders, we have two possible cap group buy alternatives. For me, these are mainly for C1,C2, but some of you may want the BG F for C9.
Choice 1 would be ask Dario to buy the Elna RJH and add them to our board shipment. This is a very nice choice and is cost effective at 0.79 Euro plus shipping twice. My guess is that these will somewhere between 3 and 5 Euros each, depending on how many of us sign up, but the final price is up to Dario.
Currently, I would go for 9 Elnas, Bob has stated interest. Anybody else?
Choice 2, if Bob can confirm the ebay supplier, I can organize buying BG F caps on ebay. In this case, the goal would be to get a group buy of 50 caps together to save money. At 50, the cost would be $10.80 per cap plus whatever shipping from me to you. If we can't get 50 together but there is good interest, I will contact the seller to see if he will do a deal for a quantity between 1 and 50. The hope would be to bring the shipping cost down.
At the moment, I would be interested in 11 BG F and Dario would be interested in 4. Which choice should we pursue?
Jac
I wouldn't pay ten cents for a "Blackgate" cap sold on eBay from Taiwan. Get real, guys. The only reason they're for sale from Taiwan and nowhere else in the world is because they're FAKE. Sorry, Bob, but I think you've been lied to.
I would sooner go back to the Twisted Pear configuration of a lesser 'lytic bypassed with a quality film. There is no other 'lytic I tried at C9 that sounded as good as the BG STD. If PK or F or whatever is even better than STD, then you probably will be disappointed if you must use, say, Silmic or any Nichicon; they're not even close. We went down that road a long time ago. C1 and C2 are a different story altogether, and I don't think you need the ultimate cap there to get excellent performance.
Is there good reason to believe that a 4v rated cap will be reliable in C9 position? I don't think one year of service is a sufficient test. On the other hand, it may be perfectly adequate. Does anyone really know? If it fails, what are the consequences? I wish I understood exactly what C9 does. If it only blocks DC, then how can the value ever get too big? Does using 470uF instead of 220uF make any sonic impact? If not, then why would 1000? Overkill in one sense, and crazy expensive, but perhaps a better option than an underrated cap or a fake one, if it fulfills its important sonic role.
Set your sonic priorities and pursue them logically.
Peace,
Tom E
I would sooner go back to the Twisted Pear configuration of a lesser 'lytic bypassed with a quality film. There is no other 'lytic I tried at C9 that sounded as good as the BG STD. If PK or F or whatever is even better than STD, then you probably will be disappointed if you must use, say, Silmic or any Nichicon; they're not even close. We went down that road a long time ago. C1 and C2 are a different story altogether, and I don't think you need the ultimate cap there to get excellent performance.
Is there good reason to believe that a 4v rated cap will be reliable in C9 position? I don't think one year of service is a sufficient test. On the other hand, it may be perfectly adequate. Does anyone really know? If it fails, what are the consequences? I wish I understood exactly what C9 does. If it only blocks DC, then how can the value ever get too big? Does using 470uF instead of 220uF make any sonic impact? If not, then why would 1000? Overkill in one sense, and crazy expensive, but perhaps a better option than an underrated cap or a fake one, if it fulfills its important sonic role.
Set your sonic priorities and pursue them logically.
Peace,
Tom E
Whoever will pay 540$ for a 220uF BG F series cap is totally insane in my book or has tons of money to throw in the air...
For much less u can get a much better film cap. Electrolytics are no match for film caps in my book but then again space is an issue...
ClarityCap TC Series Film Capacitor
I totally agree with Mundorf AG but they're 2200uF and up...
Do
For much less u can get a much better film cap. Electrolytics are no match for film caps in my book but then again space is an issue...
ClarityCap TC Series Film Capacitor
I totally agree with Mundorf AG but they're 2200uF and up...
Do
Can't see past your nose, Pinnocchio? $540 is for 50 pcs. If they were genuine, they'd almost be worth it, and I'd pay it due to previous experience with this amp/component. Many will testify that there are decent deals available, and I've bought some myself, but I have zero confidence in the integrity of anyone selling extinct parts from Taiwan on eBay. Positive feedback is not a valid indicator. It's fun to believe you've found buried treasure.
There must be another solution to this problem.
1000uF Mundorf AG (25mm diameter) is listed on their data sheet, but not listed for sale by Parts Connexion. Now THAT might be a worthwhile search and a group buy. The 2200uF is $14, so maybe 1000uF would be around $10 each. Could we get a deal on 50 or 100? That's almost worth it, if it would work in this circuit at C9 and the Mundorf sounds as good as people say it does.
Don't know where I got the idea they're for sale at PC. Guess I can't see past my nose, either!
Peace,
Tom E
There must be another solution to this problem.
1000uF Mundorf AG (25mm diameter) is listed on their data sheet, but not listed for sale by Parts Connexion. Now THAT might be a worthwhile search and a group buy. The 2200uF is $14, so maybe 1000uF would be around $10 each. Could we get a deal on 50 or 100? That's almost worth it, if it would work in this circuit at C9 and the Mundorf sounds as good as people say it does.
Don't know where I got the idea they're for sale at PC. Guess I can't see past my nose, either!
Peace,
Tom E
Sorry to be filling this thread with my ravings, but this is a key topic.
I scroll down the Mundorf data sheet and see there are CUSTOM VALUES and a wide range of sizes available. Minimum quantity is 144, delivery is 4 to 6 weeks. If there is sufficient interest from this group, I would be willing to inquire with Parts Connexion if they would broker a buy of sufficient quantity, made to our specification. Perhaps they would even carry the balance for their own sale--I'm sure this is a popular size. We could get 220uF 50v, or whatever we want, in a smaller package to fit the FE boards. How cool would that be?
Peace,
Tom E
I scroll down the Mundorf data sheet and see there are CUSTOM VALUES and a wide range of sizes available. Minimum quantity is 144, delivery is 4 to 6 weeks. If there is sufficient interest from this group, I would be willing to inquire with Parts Connexion if they would broker a buy of sufficient quantity, made to our specification. Perhaps they would even carry the balance for their own sale--I'm sure this is a popular size. We could get 220uF 50v, or whatever we want, in a smaller package to fit the FE boards. How cool would that be?
Peace,
Tom E
As a starting point 4 RJH will cost 4.5€ (incl. VAT, shipping quota and PP fees), price could lower a bit if q.ty rise.
I would not be so sure about it...
BG F are very old, they were superseded by BG FK several years ago, maybe those caps are dried but I don't think they're fake.
I've bought some FKs from Russia last year and they sound better than BG STD, if they're fake they're a good one
It would be really nice but I'm a bit skeptik on F&T (the Mundorf AG manifacturer) making a 7.5mm LS, 16mm diameter cap on demand when all AG production is snap-in compatible.
Maybe you can try to ask, if they confirm I will be interested.
Good grief Tom! You really know how to throw a wet blanket on things. I'm guessing few will be interested in trying for BG F caps after your tirade. Is it so hard to believe that some enterprising guy in Taiwan recognized that there was value in BG caps and bought some NOS?
Bob took the long chance (Bravo, Bob!) and tried them. He did his due diligence, did listening tests, and found them worthy. He has confirmed that what is available now is from the same vendor. That isn't perfectly risk free, but it is a lot more of a sure thing than the original risk he took. I'm inclined to agree with Dario, they may be dried out due to age, but are likely to be real.
Regarding the voltage rating on C9, this is how I look at it.
Let us assume that you have a line level signal coming into the amp at max volume. That would be 0.447 V peak or round it up to 0.5 volt. That is basically the voltage at the minus terminal of the LM318. Now, the op amp's mission in life is to make the difference between the plus and minus input equal to zero. Since the plus input of the 318 is the same voltage as C9 relative to ground, the most voltage that C9 could see would be 0.5 volts.
Do it another way. Take the 1/2 volt * gain (30) and you get 15 volts max at the output. Now put the 15 volts at the voltage divider formed by R7 and R10. That means that C9 is at about 1/2 volt above ground.
The function of C9/R10 is to decrease the gain of the 318 at low frequencies as the 318 isn't so stable there. That means that at low frequencies, the impedance of the C9/R10 filter gets bigger. As it does that, the output gets smaller and the voltage at C9 says at about 1/2 volt.
Of course, I've simplified and taken short cuts, but I think that 4 or 6.3 volt caps appear to be plenty high enough voltage rating for C9.
Jac
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Thanks Dario. After writing my last post, I think I have convinced myself that the BG PK is good for C9, so I guess I don't really need any of BG F. That means I am mainly looking for C1, C2.
I am in for 9 Elna RJH. I know these are nice caps, so they are worth a little extra.
Jac
At the time I bought those caps I was unfortunately involved (never again 
) in one of those circular disputes about changes in cap performance over time. I believe I was tuned in to whether what I heard was in my ear or in my mind - playing tricks with my brain I'll just say the qualities I perceived were as valid as any other comparisons made. The overall sound of the RC builds has sweetened over the months since the BG Fs were installed. Don't know what if anything might happen with extended use.
Along with several other elements, I plan to do a bit of the "Swap and Twirl" dance on the final boards during that build. I have the confidence to buy those caps again but am just as interested in auditioning any other option developed here on the thread.
P.S. You almost lost me Saturday evening! After listening to every track on this CD - twice, The FEs and the Sunflowers had me ready to find St. Peter and join the jam session. Quincy usually over-records, but the FEs accurately reproduced everything from room shaking bottom synths and timpani , tiny bells, massive group vocals and instant dynamic reversals. Gonna go play it again when I finish this note 
Dario, you've created a monster amp !!
) in one of those circular disputes about changes in cap performance over time. I believe I was tuned in to whether what I heard was in my ear or in my mind - playing tricks with my brain I'll just say the qualities I perceived were as valid as any other comparisons made. The overall sound of the RC builds has sweetened over the months since the BG Fs were installed. Don't know what if anything might happen with extended use.Along with several other elements, I plan to do a bit of the "Swap and Twirl" dance on the final boards during that build. I have the confidence to buy those caps again but am just as interested in auditioning any other option developed here on the thread.
P.S. You almost lost me Saturday evening! After listening to every track on this CD - twice, The FEs and the Sunflowers had me ready to find St. Peter and join the jam session.
Quincy usually over-records, but the FEs accurately reproduced everything from room shaking bottom synths and timpani , tiny bells, massive group vocals and instant dynamic reversals. Gonna go play it again when I finish this note Dario, you've created a monster amp !!
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More on C9 voltage rating
Jac, what you described apply on normal working conditions but C9, in theory, can be exposed to full rail voltage (35V) in case of failure.
It's for this reason that I suggest to mount them only after positive tests on modules and to keep some spares in case of problems.
In a properly used and heatsinked working build it's very unlikey that those little PKs will ever have any problems.
Jac, what you described apply on normal working conditions but C9, in theory, can be exposed to full rail voltage (35V) in case of failure.
It's for this reason that I suggest to mount them only after positive tests on modules and to keep some spares in case of problems.
In a properly used and heatsinked working build it's very unlikey that those little PKs will ever have any problems.
I totally agree. So far, I have used lesser, higher voltage caps to prove the build before installing anything low voltage. As long as I think slowly, I will do the same on these builds.
Faston Connections at the Speaker In and Out
Although I know that Tom and others prefer never to use Faston's or disconnect terminals, it is the "normal" way to attach the speaker wires to a MyRef. I've been looking around for alternatives that are better materials without going crazy with the Furutech/WBT expensive alternatives. I found these industrial parts from Mouser that might work.
This is a case of flipping the connection. It uses a female board mount made from brass with a tin over copper plating. If you look at the Mouser page, you won't see what you are getting. Look at the Data Sheet.
1217080-1 TE Connectivity / AMP | Mouser
Once you get the female on the board, these are two sizes of copper, male wire mount disconnects. The small one (18-22 AWG) is gold plated copper. The bigger one (10-12 AWG) is also available in other wire sizes and is tin plated copper. Again, be careful by reading the data sheets. Some of these are mis-specified as copper when the data sheet shows brass.
19022-0004 Molex | Mouser
19004-0012 Molex | Mouser
In the end, these are a pretty low cost alternative.
Although I know that Tom and others prefer never to use Faston's or disconnect terminals, it is the "normal" way to attach the speaker wires to a MyRef. I've been looking around for alternatives that are better materials without going crazy with the Furutech/WBT expensive alternatives. I found these industrial parts from Mouser that might work.
This is a case of flipping the connection. It uses a female board mount made from brass with a tin over copper plating. If you look at the Mouser page, you won't see what you are getting. Look at the Data Sheet.
1217080-1 TE Connectivity / AMP | Mouser
Once you get the female on the board, these are two sizes of copper, male wire mount disconnects. The small one (18-22 AWG) is gold plated copper. The bigger one (10-12 AWG) is also available in other wire sizes and is tin plated copper. Again, be careful by reading the data sheets. Some of these are mis-specified as copper when the data sheet shows brass.
19022-0004 Molex | Mouser
19004-0012 Molex | Mouser
In the end, these are a pretty low cost alternative.
Attachments
.... the FEs accurately reproduced everything from room shaking bottom synths and timpani , tiny bells, massive group vocals and instant dynamic reversals. Gonna go play it again when I finish this note
Dario, you've created a monster amp !!
Yep. These amps sound absolutely great! The only problem is that I now have an image of Bob dancing around his living room stuck in my mind.
Jac
I would, instead, use the holes for bare wire no cost at all and best result...
Even better!
Any idea what wire gauge will fit in the hole?
Drill is 2.2 mm / 0,0866 in, should be AWG12
Alternate better connectors (yet to be tested for fit):
571-216843-1 (Phosphor bronze faston male PCB Connector)
571-42437-5 (Phosphor bronze faston female connector)
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Never mind, I can answer my own question. It looks like 13 gauge stranded, maybe 12 gauge if you push it.
Jac
Perhaps I was harsh in my condemnation of parts from Taiwan. Could there possibly be one honest person there selling the last of the world's supply? Yes, they are very enterprising, and counterfeiting could be a lucrative occupation. Is there any definitive test of legitimacy? If you guys are happy with them, perception is everything.
Jac, thanks for the explanation of the circuit. Now I understand the function of C9 and the other parts there. As you all have proven, if the amp functions properly, low voltage parts are adequate. Carry on.
If C9 functions as a high pass, its value establishes the corner. Is it supposed to affect subsonic frequencies or merely block DC? If subsonic, how low is too low? Dario, what differences did you notice between 220uF and 470uF? Perhaps as Andrew T maintained all along, that really is the limiting factor for bass output of the MyRef. In that case, what hazards would a larger value pose to performance of the amp? Would there be any negative sonic impact? Does anyone use value other than 220uF, and what does that do to the bass?
Peace,
Tom E
Jac, thanks for the explanation of the circuit. Now I understand the function of C9 and the other parts there. As you all have proven, if the amp functions properly, low voltage parts are adequate. Carry on.
If C9 functions as a high pass, its value establishes the corner. Is it supposed to affect subsonic frequencies or merely block DC? If subsonic, how low is too low? Dario, what differences did you notice between 220uF and 470uF? Perhaps as Andrew T maintained all along, that really is the limiting factor for bass output of the MyRef. In that case, what hazards would a larger value pose to performance of the amp? Would there be any negative sonic impact? Does anyone use value other than 220uF, and what does that do to the bass?
Peace,
Tom E
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