*Bump* just for the record:
0.1uF/100V/15mm Wima FKP3 (film/foil) is audibly superb at C4 - much better than MKP10 or MKP2 of the same value. The only problem is the size - it will probably fit with some bending of leads in a TP v1.2 and my v1.3 Rev C boards. No bending of leads required on a v1.4 board - it's a drop-in replacement.
Audible improvement - micro-detail, air, resolution, reduced glare (e.g. trumpets, cymbals) in the mids, better voice and instrument separation.
0.1uF/100V/15mm Wima FKP3 (film/foil) is audibly superb at C4 - much better than MKP10 or MKP2 of the same value. The only problem is the size - it will probably fit with some bending of leads in a TP v1.2 and my v1.3 Rev C boards. No bending of leads required on a v1.4 board - it's a drop-in replacement.
Audible improvement - micro-detail, air, resolution, reduced glare (e.g. trumpets, cymbals) in the mids, better voice and instrument separation.
i have mundorf supreme theremuch bending and extension required
Sell it, and paid your debits
Alternate transistor?
I just obtained a MyRef RevC board and am sourcing parts from mouser and digikey in the US.
The schematic included with my board and several BoM here call for BC546 or BC546CTA specifically for Q2 and Q3. I cannot find this in stock at mouser or digikey. Can someone point me toward a suitable in stock replacement?
I just obtained a MyRef RevC board and am sourcing parts from mouser and digikey in the US.
The schematic included with my board and several BoM here call for BC546 or BC546CTA specifically for Q2 and Q3. I cannot find this in stock at mouser or digikey. Can someone point me toward a suitable in stock replacement?
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Any BC546 hFE grade should work - I've used BC546B there for ages without problems. In a pinch, BC547A or B should also work. It has sufficient Vceo (45 V, IIRC) for that application - the protection relay rail doesn't exceed +24..28V maximum.
Hello,
I've tried 1uf K75-10 bypassed by a 820pf Teflon FT-1 on my tweeter crossover... the original cap on crossover is an inexpensive MCap by Mundorf.
It was quite difficult to hear the differences between the two caps, maybe it depends from the crossover design: a parallel RC (9ohm-1uf) in series with the high-pass capacitor (4,7uf) and I changed only the 1uf cap… But, in the end I preferred the MCap because it is more sweet with the same detail.
I don't now if trying the K75-10 in C13 (now I have Evox Rifa), should I expect a more audible change ? Is it even worth trying ?
Bye
I've tried 1uf K75-10 bypassed by a 820pf Teflon FT-1 on my tweeter crossover... the original cap on crossover is an inexpensive MCap by Mundorf.
It was quite difficult to hear the differences between the two caps, maybe it depends from the crossover design: a parallel RC (9ohm-1uf) in series with the high-pass capacitor (4,7uf) and I changed only the 1uf cap… But, in the end I preferred the MCap because it is more sweet with the same detail.
I don't now if trying the K75-10 in C13 (now I have Evox Rifa), should I expect a more audible change ? Is it even worth trying ?
Bye
Hi
This is my first post although I have been lurking here for many months. In fact I’ve read so much about the My_Ref amp that I think of Dario, Siva and Tom as friends even though they don’t know me - maybe Siva does a bit since I bought a couple of boards from him.
It’s now time to start assembling the amp so I’m hoping to get some last minute advice. I realise that I’m late to the party, but it’s never too late to build a good amp!
I will be ordering the BOM through Mouser’s Thailand website. All other websites I can find either do not provide information in English or charge way too much for shipping to Thailand. Local dealers stock very little in the way of quality components and when they do I’m very wary of fakes. What I am trying to do is build the best amp I can using standard industrial components, and I would be particularly interested in the latest thinking in a few areas. Please note I will be building a RevC not RevFE
1. Compensation & C10/C34 – I intend to use standard RevC compensation. Does anyone have a better idea? I will be using CDE silver micas.
2. Electrolytic capacitors – What should I use in a post Black Gate world? I am intending to use Nichicon KZ’s for C1,C2 &C9 and FG’s for C6 & C11. Mouser stocks Panasonics, Nichicons and some lower voltage Elna Silmic 11’s. but no Cerafines.
3. C13 – I am leaning towards Russian K73-16’s. They are cheap and one of the few components that can be bought reliably off ebay.
4. R13 – Is the Caddock MK132V really worth the extra cost over a standard KOA CFR?
Any other advice would be very gratefully received
Regards
Fred
This is my first post although I have been lurking here for many months. In fact I’ve read so much about the My_Ref amp that I think of Dario, Siva and Tom as friends even though they don’t know me - maybe Siva does a bit since I bought a couple of boards from him.
It’s now time to start assembling the amp so I’m hoping to get some last minute advice. I realise that I’m late to the party, but it’s never too late to build a good amp!
I will be ordering the BOM through Mouser’s Thailand website. All other websites I can find either do not provide information in English or charge way too much for shipping to Thailand. Local dealers stock very little in the way of quality components and when they do I’m very wary of fakes. What I am trying to do is build the best amp I can using standard industrial components, and I would be particularly interested in the latest thinking in a few areas. Please note I will be building a RevC not RevFE
1. Compensation & C10/C34 – I intend to use standard RevC compensation. Does anyone have a better idea? I will be using CDE silver micas.
2. Electrolytic capacitors – What should I use in a post Black Gate world? I am intending to use Nichicon KZ’s for C1,C2 &C9 and FG’s for C6 & C11. Mouser stocks Panasonics, Nichicons and some lower voltage Elna Silmic 11’s. but no Cerafines.
3. C13 – I am leaning towards Russian K73-16’s. They are cheap and one of the few components that can be bought reliably off ebay.
4. R13 – Is the Caddock MK132V really worth the extra cost over a standard KOA CFR?
Any other advice would be very gratefully received
Regards
Fred
Fred,
Never too late to build a good amp, and the MyRef C is a GREAT amplifier, even with standard quality parts. The only reason I decided to attempt to improve the amp by using better parts is because I recognized the potential of the basic design, built the first time with very cheap, standard quality (perhaps less!) parts. Anything beyond that will make the amp sound better, but there is nothing wrong with the basic level construction. Don't worry about not having all the golden ear stuff.
Use the original compensation scheme. Mauro, the original designer, spent a lot of time selecting it, and it sounds excellent. Dario claims his is better, but I disagree. Those particular parts are cheap enough that you could try both to find out for yourself.
The only 'lytic caps I did not like at C9 were Silmic II's. Dull, flat, lifeless. I preferred Panny FM's, but others liked the sound of Nichicon's there. When not using BG in C9, consider using a small film bypass at C21. You get a little smoother highs with more transparency. For all the other caps, I don't think it makes a whole lot of difference, but I used FM's. You could mix different brands to avoid too much of one sound.
I can't help you with Russian caps for C13. Lots of people like them, so they are probably worth the small investment required.
I did not detect much change with better resistor at R13. Carbon film is probably the best, but it won't make or break the amp. I would avoid KOA's with magnetic end caps, but that's just me. Vishay/Dale are non-mag.
Get building, and let us know how it turns out. Don't be a lurker, and someday someone will read your advice, too.
Peace,
Tom E
Never too late to build a good amp, and the MyRef C is a GREAT amplifier, even with standard quality parts. The only reason I decided to attempt to improve the amp by using better parts is because I recognized the potential of the basic design, built the first time with very cheap, standard quality (perhaps less!) parts. Anything beyond that will make the amp sound better, but there is nothing wrong with the basic level construction. Don't worry about not having all the golden ear stuff.
Use the original compensation scheme. Mauro, the original designer, spent a lot of time selecting it, and it sounds excellent. Dario claims his is better, but I disagree. Those particular parts are cheap enough that you could try both to find out for yourself.
The only 'lytic caps I did not like at C9 were Silmic II's. Dull, flat, lifeless. I preferred Panny FM's, but others liked the sound of Nichicon's there. When not using BG in C9, consider using a small film bypass at C21. You get a little smoother highs with more transparency. For all the other caps, I don't think it makes a whole lot of difference, but I used FM's. You could mix different brands to avoid too much of one sound.
I can't help you with Russian caps for C13. Lots of people like them, so they are probably worth the small investment required.
I did not detect much change with better resistor at R13. Carbon film is probably the best, but it won't make or break the amp. I would avoid KOA's with magnetic end caps, but that's just me. Vishay/Dale are non-mag.
Get building, and let us know how it turns out. Don't be a lurker, and someday someone will read your advice, too.
Peace,
Tom E
Hi Fred,
1. You can use FE comp., Tom's suggestion of experimenting both and decide later is a good one.
2. Use a Wima FKP2 22nF bypass and you'll have near BG sound with Silmics II (better gold version from eBay) or Nichicon FGs
3. I suggest you to buy from Mouser Vishay V730P o V735P instead.
4. It depends on how you value cleaniness and neutrality, the price difference is really big.
Thank you Tom and Dario for your replies.
Maybe I’m obsessing over issues that are not critically important. As Tom points out the amp would sound very good with ordinary components, and that may be good enough for me in my system. What I need to do is just get on and build the amp. If improvement is needed then I can use your suggestions as a starting point.
After considerable thought I’ve made the following decisions.
1. If will use the RevC compensation – it’s the logical place to start.
2. I will order both KZs and FGs for C9 from Mouser. I already have a couple of Silmic 11s that I bought in the Ban Mo electronics market in Bangkok a few weeks ago. I don’t know if they are genuine, but suspect that they may be “grey market” items and are probably worth a try.
3. My gut feeling is to go with the Russian capacitor. I may also add a couple of Vishay capacitors to the Mouser order although they are fairly expensive. Dario, I have to admit I don’t understand why you would recommend a metallised capacitor over a film and foil for signal duties?
4. I will probably go with the Caddock resistors. While they are ridiculously more expensive than standard CFR, they don’t add much to the overall cost of the amp. If I used CFR then I would always be wondering if the Caddocks would have been better.
Once again thanks for your input, and I’ll let you know how I get on.
Regards
Fred
Maybe I’m obsessing over issues that are not critically important. As Tom points out the amp would sound very good with ordinary components, and that may be good enough for me in my system. What I need to do is just get on and build the amp. If improvement is needed then I can use your suggestions as a starting point.
After considerable thought I’ve made the following decisions.
1. If will use the RevC compensation – it’s the logical place to start.
2. I will order both KZs and FGs for C9 from Mouser. I already have a couple of Silmic 11s that I bought in the Ban Mo electronics market in Bangkok a few weeks ago. I don’t know if they are genuine, but suspect that they may be “grey market” items and are probably worth a try.
3. My gut feeling is to go with the Russian capacitor. I may also add a couple of Vishay capacitors to the Mouser order although they are fairly expensive. Dario, I have to admit I don’t understand why you would recommend a metallised capacitor over a film and foil for signal duties?
4. I will probably go with the Caddock resistors. While they are ridiculously more expensive than standard CFR, they don’t add much to the overall cost of the amp. If I used CFR then I would always be wondering if the Caddocks would have been better.
Once again thanks for your input, and I’ll let you know how I get on.
Regards
Fred
I built a MyRefC a couple of years ago and it has worked great since. This weekend I was tinkering again and I have a newbie question:
The amp makes a horrible noise when there is nothing connected to the input. Is this something unique to my build or does this happen with all MyRefC? Is there anything that can be done to make the amp more forgiving if it is turned on without the input connected?
Thanks.
The amp makes a horrible noise when there is nothing connected to the input. Is this something unique to my build or does this happen with all MyRefC? Is there anything that can be done to make the amp more forgiving if it is turned on without the input connected?
Thanks.
A little hum is possible with the inputs disconnected, but not any great noise. Check your grounding carefully for ground loops. Disconnect the PGND to Chassis Earth connection if you have it - it's the source of several unintentional grounding issues. Ensure that the signal ground shields at the input RCAs are not shorted to the chassis - use insulating washers if possible.
is there a 100k to 2M2 resistor fitted across the input RCA?
Shorting this out with a zero or low value dummy load should get the noise + hum down to <0.2mVac and often a 0.1mVac resolution will indicate 0.0mVac telling you that noise plus hum is less than 0.05mVac (<50uVac).
When the shorting plug is removed, the output noise will increase substantially. Expect between 0.3mVac and 1mVac
If it's much more than that there is something wrong.
Shorting this out with a zero or low value dummy load should get the noise + hum down to <0.2mVac and often a 0.1mVac resolution will indicate 0.0mVac telling you that noise plus hum is less than 0.05mVac (<50uVac).
When the shorting plug is removed, the output noise will increase substantially. Expect between 0.3mVac and 1mVac
If it's much more than that there is something wrong.
Thanks for the reply. With a 1M resistor across the RCA I read .1Vac across the speaker terminals. With the RCA inputs shorted I read .000 across one speaker terminal and .010 across the other. Looks like I have some work to get the noise down, and probably get a multimeter with better resolution.
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