Hello all,
I've been away from this amp for some time & I must come back. I look forward to trying some of the upgrades but must deal with this issue first:
I have hum on open input / none with shorted input.
I want to try the above solutions. IF I use them both, are they parallel or series?
I've been away from this amp for some time & I must come back. I look forward to trying some of the upgrades but must deal with this issue first:
I have hum on open input / none with shorted input.
I have mains ground going to a bolt in the chassis. I have transformer CT going to the same bolt.
I want to try the above solutions. IF I use them both, are they parallel or series?
Sure, Originally I did not. I have it spade-connected on the PC board and jumpered to the chassis ground. I have tried that as a way to eliminate the hum I experience. Here's where I am now:
Open input, no hum
Shorted input, no hum
Source connected, hum
So I'm going for another source right now to eliminate that possibility.
Last edited:
Okay, I just emailed with Mauro and TWO THINGS:
1: Thats not him. Some other Italian dude with same name, however Mauro lives in the Alps and enjoys climbing.
2: GROUP BUY!
Twisted Pear has said it is okay for me to run a group buy for the boards they layed out. I will be using their gerbers.
Mauro says it is okay for me to sell them and if I become a millionaire I am to remember him
So I have talked to Clave Freeman and to Madisonears. They both had awesome sounding systems with the MyRef. I would say they tested for months tweaking the components. The design is the same with the exception of the removal of 4 caps. Other than that they experimented with caps A LOT and came to conclusions that more or less agreed with each other. So we have a few BOMs. One from Dario (clavefreeman) and one from Tom(madisonears). We are not going to discuss the BOM or price immediately because I have not costed them out as I have NO idea of how many people are interested. Lets see what the interest level is and then I will investigate cost.
The options are
1: Boards only
or
2: Premium Kits
I dont intend to do a minimalist kit. If you want the cheap parts the fact is they dont cost much but if we do a group buy for premium parts we might all be able to afford an amp we would not have been able to afford alone.
So I will go ahead and post the BOMs but lets talk interest first because talking about the BOM will only slow things down to a crawl.
Dario responded first to my request for a BOM so I post his first. Here is what he said:
Hi Uriah,
the most important improvement in BOM is, IMHO, using Wima polypropilene caps:
C30 Wima FKP2 1nF 100V 505-FKP21000/100/5
C21 Wima FKP2 22nF 63V (to be mounted in the bottom side of PCB) 505-FKP20.022/63/2.5
C4, C5 Wima MKP4 100nF 250V 7.5 mm lead spacing 505-MKP4.1/250/10
C7 Wima MKP2 100nF 63V 505-MKP20.1/100/5
C32 Wima FKP2 150 pF 100V 505-FKP2150/100/2.5
C17, C18, C19, C20 100nF X7R ceramic (optional, better if not used at all)
As you know these suggestions are in common with Tom.
Regarding elcos I suggest Silmics in C9,C6,C11.
With Wimas in place C9 is also good with FMs (but not as good as with Silmics) and I suppose with BlackGates too.
In C6 and C11 FMs are not so good, IMHO Silmics and Nichicons Muse KZ are better.
In C1, C2 FMs are good.
For the main resorvoir caps I would suggest Nichicon KS, specific for audio (647-LKS1H103MESB)
Regarding resistors I've used Takmans and Dales CMF/RN55, Tom used PRPs, but I suppose that all CMF/RN55 would be a nice choice, the 0.1% RC55Y in kits probably were good too.
You can have a quote for Takmans here.
Dario
Okay then he emailed again and said:
Hi again Uriah,
All Wimas and ceramics are perfect fits, except C21 that has to be mounted on the bottom side of pcb.
C3,C8:
Nichicon KSs are perfect fits, pay attention to the code, it must end with MESB (30 mm diameter).
C6, C11:
Nichicons KZ 100uF 25V Perfect fit
Elna Silmic II 100uF 35V Perfect fit
C9:
With C13 on board no cap would mount perfectly, except:
Elna Silmic II 220uF 35V TIGHT fit
(50V version is probably better and safer but doesn't fit)
With C13 off-board quite all caps fits
Regarding C6, C11 be aware that KZs needs 100 hours burn in and Silmics 50 hours, initially both give an unbalanced sound, closed and with too much bass.
KZs sounds bigger, warmer and a bit less detailed
Silmics are clear and open with a lot of reverbs and details
FMS are clear and open good detail, much less reverbs than Silmics, a bit harsh
Dario
So then Tom emailed me via the forum and said this:
Uriah,
I finally got around to making a BOM. I cannot say that every component I used is necessary or worth the cost. I do know that these are the BEST amps I have ever had in my system. They are insanely good. That has been corroborated by others whose opinions I value. Some of these components are ridiculously expensive, but whatever compromises one makes in order to cheapen these amps might have an impact on the quality of the sound.
If you do another group deal, I suggest you provide only boards. It will be so much easier, and then people can decide if they want to follow the premium BOM. All of these items are available from Mouser, Parts Connexion, or Take Five Audio.
D2-D3-D4 1N4001 Fairchild
Q2-Q3 BC546 Fairchild
Q1 BC639 Fairchild
ZD1, ZD2 BZX85C12 Fairchild
C1, C2, C14 220uF Panasonic FM 50V 20%
C3, C8 12000uF (insert favorite brand) 50V 20%
C4, C5 100nF WIMA MKP4 100V 5% Lead Free
C6, C11, C16 100uF Panasonic FM 35V 20%
C7 100nF WIMA MKP2 63V 5% Lead Free
C9 220uF Blackgate STD 50V
C10 22pF Kemet Golden Max 200V 5%
C12 220pF Vishay/BC Mono Kap 100V 5%
C13 0.68uF Fostex copper/tin foil and PPTA film 240V (mounted off the PCB, with leads wrapped in Teflon tape)
C15 22uF Panasonic FM 50V 20%
C17, C18, C19, C20 not used
C21 22nf WIMA MKP2 100V 10% (mounted under the PCB)
C30 1nF WIMA MKP10 1000V 10%
C32 150pF Kemet Golden Max 200V 5%
C34 10pF Kemet MLCC 200V 5%
U1 LM318N National Semiconductor
IC1-2 LM3886 National Semiconductor
D1 GBJ1504 Taitron
R1, R4 1K Yageo 2W 5%
R2 33K PRP 1/4W 1%
R3 0.5 ohm Caddock MP2060 60W 1%
R5, R8 22K1 PRP 1/4W 0.1% (matched by hand)
R6, R9 47K5 PRP 1/4W 0.1% (matched by hand)
R7 12K0 PRP 1/4W 1%
R10 390 Shinkoh Tantalum 1/2W 1%
R11 1 KOA Speer 1/4W 1%
R12 3K3 Shinkoh Tantalum 1/2W 1%
R13 100K PRP1/4W 1%
R14 470 PRP 1W 5%
R15, R16 75K PRP 1/4W 1%
R19 10K PRP 1/4W 1%
R20 47K PRP 1/4W 1%
R21 220K PRP 1/4W 1%
R22 8K2 PRP 1/4W 1%
R37 3K3 PRP 1/4W 1%
R39 470K PRP 1/4W 1%
R43 22K PRP 1/4W 1%
R42 47 PRP 1/4W 1%
R23 6K8 PRP 1/2W 1%
RELAY1 SPDT 24VDC Omron
Heatsink for Caddock resistor Aavid Thermalloy 551002B00000G, which will require moderate trimming to fit among the other PCB components
Ohno UPOCC solid core copper with Teflon insulation for all hook-up wire (available from Take Five Audio)
Vampire pure copper RCA’s and binding posts (no brass content allowed!)
Peace,
Tom E
So thats the deal folks. Lets talk about it for a month or so and then we will decide on ordering boards or boards and BOMs or nothing. Now mind you I will have NO idea as to price til I have a number of people interested. To go get pricing for 100 is just not smart and would not help us any as it would be a lot cheaper than 50 or 20 and it would cause people to question pricing if I quote 100 and end up with 20. So show your interest, know that premium parts means premium pricing and that group buy is going to make it a lot more affordable than otherwise.
Uriah
1: Thats not him. Some other Italian dude with same name, however Mauro lives in the Alps and enjoys climbing.
2: GROUP BUY!
Twisted Pear has said it is okay for me to run a group buy for the boards they layed out. I will be using their gerbers.
Mauro says it is okay for me to sell them and if I become a millionaire I am to remember him
So I have talked to Clave Freeman and to Madisonears. They both had awesome sounding systems with the MyRef. I would say they tested for months tweaking the components. The design is the same with the exception of the removal of 4 caps. Other than that they experimented with caps A LOT and came to conclusions that more or less agreed with each other. So we have a few BOMs. One from Dario (clavefreeman) and one from Tom(madisonears). We are not going to discuss the BOM or price immediately because I have not costed them out as I have NO idea of how many people are interested. Lets see what the interest level is and then I will investigate cost.
The options are
1: Boards only
or
2: Premium Kits
I dont intend to do a minimalist kit. If you want the cheap parts the fact is they dont cost much but if we do a group buy for premium parts we might all be able to afford an amp we would not have been able to afford alone.
So I will go ahead and post the BOMs but lets talk interest first because talking about the BOM will only slow things down to a crawl.
Dario responded first to my request for a BOM so I post his first. Here is what he said:
Hi Uriah,
the most important improvement in BOM is, IMHO, using Wima polypropilene caps:
C30 Wima FKP2 1nF 100V 505-FKP21000/100/5
C21 Wima FKP2 22nF 63V (to be mounted in the bottom side of PCB) 505-FKP20.022/63/2.5
C4, C5 Wima MKP4 100nF 250V 7.5 mm lead spacing 505-MKP4.1/250/10
C7 Wima MKP2 100nF 63V 505-MKP20.1/100/5
C32 Wima FKP2 150 pF 100V 505-FKP2150/100/2.5
C17, C18, C19, C20 100nF X7R ceramic (optional, better if not used at all)
As you know these suggestions are in common with Tom.
Regarding elcos I suggest Silmics in C9,C6,C11.
With Wimas in place C9 is also good with FMs (but not as good as with Silmics) and I suppose with BlackGates too.
In C6 and C11 FMs are not so good, IMHO Silmics and Nichicons Muse KZ are better.
In C1, C2 FMs are good.
For the main resorvoir caps I would suggest Nichicon KS, specific for audio (647-LKS1H103MESB)
Regarding resistors I've used Takmans and Dales CMF/RN55, Tom used PRPs, but I suppose that all CMF/RN55 would be a nice choice, the 0.1% RC55Y in kits probably were good too.
You can have a quote for Takmans here.
Dario
Okay then he emailed again and said:
Hi again Uriah,
All Wimas and ceramics are perfect fits, except C21 that has to be mounted on the bottom side of pcb.
C3,C8:
Nichicon KSs are perfect fits, pay attention to the code, it must end with MESB (30 mm diameter).
C6, C11:
Nichicons KZ 100uF 25V Perfect fit
Elna Silmic II 100uF 35V Perfect fit
C9:
With C13 on board no cap would mount perfectly, except:
Elna Silmic II 220uF 35V TIGHT fit
(50V version is probably better and safer but doesn't fit)
With C13 off-board quite all caps fits
Regarding C6, C11 be aware that KZs needs 100 hours burn in and Silmics 50 hours, initially both give an unbalanced sound, closed and with too much bass.
KZs sounds bigger, warmer and a bit less detailed
Silmics are clear and open with a lot of reverbs and details
FMS are clear and open good detail, much less reverbs than Silmics, a bit harsh
Dario
So then Tom emailed me via the forum and said this:
Uriah,
I finally got around to making a BOM. I cannot say that every component I used is necessary or worth the cost. I do know that these are the BEST amps I have ever had in my system. They are insanely good. That has been corroborated by others whose opinions I value. Some of these components are ridiculously expensive, but whatever compromises one makes in order to cheapen these amps might have an impact on the quality of the sound.
If you do another group deal, I suggest you provide only boards. It will be so much easier, and then people can decide if they want to follow the premium BOM. All of these items are available from Mouser, Parts Connexion, or Take Five Audio.
D2-D3-D4 1N4001 Fairchild
Q2-Q3 BC546 Fairchild
Q1 BC639 Fairchild
ZD1, ZD2 BZX85C12 Fairchild
C1, C2, C14 220uF Panasonic FM 50V 20%
C3, C8 12000uF (insert favorite brand) 50V 20%
C4, C5 100nF WIMA MKP4 100V 5% Lead Free
C6, C11, C16 100uF Panasonic FM 35V 20%
C7 100nF WIMA MKP2 63V 5% Lead Free
C9 220uF Blackgate STD 50V
C10 22pF Kemet Golden Max 200V 5%
C12 220pF Vishay/BC Mono Kap 100V 5%
C13 0.68uF Fostex copper/tin foil and PPTA film 240V (mounted off the PCB, with leads wrapped in Teflon tape)
C15 22uF Panasonic FM 50V 20%
C17, C18, C19, C20 not used
C21 22nf WIMA MKP2 100V 10% (mounted under the PCB)
C30 1nF WIMA MKP10 1000V 10%
C32 150pF Kemet Golden Max 200V 5%
C34 10pF Kemet MLCC 200V 5%
U1 LM318N National Semiconductor
IC1-2 LM3886 National Semiconductor
D1 GBJ1504 Taitron
R1, R4 1K Yageo 2W 5%
R2 33K PRP 1/4W 1%
R3 0.5 ohm Caddock MP2060 60W 1%
R5, R8 22K1 PRP 1/4W 0.1% (matched by hand)
R6, R9 47K5 PRP 1/4W 0.1% (matched by hand)
R7 12K0 PRP 1/4W 1%
R10 390 Shinkoh Tantalum 1/2W 1%
R11 1 KOA Speer 1/4W 1%
R12 3K3 Shinkoh Tantalum 1/2W 1%
R13 100K PRP1/4W 1%
R14 470 PRP 1W 5%
R15, R16 75K PRP 1/4W 1%
R19 10K PRP 1/4W 1%
R20 47K PRP 1/4W 1%
R21 220K PRP 1/4W 1%
R22 8K2 PRP 1/4W 1%
R37 3K3 PRP 1/4W 1%
R39 470K PRP 1/4W 1%
R43 22K PRP 1/4W 1%
R42 47 PRP 1/4W 1%
R23 6K8 PRP 1/2W 1%
RELAY1 SPDT 24VDC Omron
Heatsink for Caddock resistor Aavid Thermalloy 551002B00000G, which will require moderate trimming to fit among the other PCB components
Ohno UPOCC solid core copper with Teflon insulation for all hook-up wire (available from Take Five Audio)
Vampire pure copper RCA’s and binding posts (no brass content allowed!)
Peace,
Tom E
So thats the deal folks. Lets talk about it for a month or so and then we will decide on ordering boards or boards and BOMs or nothing. Now mind you I will have NO idea as to price til I have a number of people interested. To go get pricing for 100 is just not smart and would not help us any as it would be a lot cheaper than 50 or 20 and it would cause people to question pricing if I quote 100 and end up with 20. So show your interest, know that premium parts means premium pricing and that group buy is going to make it a lot more affordable than otherwise.
Uriah
Uriah and all,
There is a typo in my BOM, and it will bring it into even closer agreement with Dario's BOM: C21 is actually FKP, not MKP. The value is somewhat flexible. I am using the 22nF that Dario recommends, but that value was selected to combine with using an Elna Silmic II at C9. Since I absolutely disliked Silmics there because they completely killed the high frequencies, I substituted the Blackgate there, which is pure and sweet. I did not experiment any more with the value of C21 because it seems to be making some pretty nice music. I suspect that increasing the value to that originally suggested by Mauro, 100nF, would possibly extend the high frequency response. Use of FKP there, not MKP, is essential. The FKP is a superior cap in every way, but it is not available in higher values.
I think that the brand of resistor is not so critical except in two locations. Any "better" brand would be adequate and better than Xicon. The two critical locations, R10 and R12, should use the best available. For me, that means Shinkoh tantalum. There may be others available at better prices.
There is one item not available from the sources I gave: the Fostex cap for C13, which is crucial for the sound of this amp, is available only from Madisound, as far as I know. I live in Madison so I know them, but I have no direct connection with Madisound. Builders may have other favorite caps that they prefer to try there. I would offer only one suggestion: use a true film and foil cap there, and not a metallized film. The Fostex is unknown, but better than any other I tried there. Readers of this thread will have seen my other posts regarding comparisons.
Thanks for starting this up again. I will buy several boards and possibly complete kits if you put a package deal together. Everyone who hears these amps wants them.
Peace,
Tom E
There is a typo in my BOM, and it will bring it into even closer agreement with Dario's BOM: C21 is actually FKP, not MKP. The value is somewhat flexible. I am using the 22nF that Dario recommends, but that value was selected to combine with using an Elna Silmic II at C9. Since I absolutely disliked Silmics there because they completely killed the high frequencies, I substituted the Blackgate there, which is pure and sweet. I did not experiment any more with the value of C21 because it seems to be making some pretty nice music. I suspect that increasing the value to that originally suggested by Mauro, 100nF, would possibly extend the high frequency response. Use of FKP there, not MKP, is essential. The FKP is a superior cap in every way, but it is not available in higher values.
I think that the brand of resistor is not so critical except in two locations. Any "better" brand would be adequate and better than Xicon. The two critical locations, R10 and R12, should use the best available. For me, that means Shinkoh tantalum. There may be others available at better prices.
There is one item not available from the sources I gave: the Fostex cap for C13, which is crucial for the sound of this amp, is available only from Madisound, as far as I know. I live in Madison so I know them, but I have no direct connection with Madisound. Builders may have other favorite caps that they prefer to try there. I would offer only one suggestion: use a true film and foil cap there, and not a metallized film. The Fostex is unknown, but better than any other I tried there. Readers of this thread will have seen my other posts regarding comparisons.
Thanks for starting this up again. I will buy several boards and possibly complete kits if you put a package deal together. Everyone who hears these amps wants them.
Peace,
Tom E
