Some of the pads on the solder side do not have traces, if the solder does not flow to the component side via through hole, it is possible the connection is not made. Also, if a through hole goes bad, and the solder did not flow through, you also have lost connection. Lead free solder generally is not so good at flowing.
Yeah, looks like PreSapian's gone to town with full livery and makeup 🙂.
On a more serious note, Black Gates are not needed for the relay protection circuitry - in fact the slow break-in may cause sub-optimal relay operation for a while. You may want to replace it with stock 220uF Nichicon PW or Chemicon KY or similar, nothing fancy. Same goes for the Allen-Bradleys in the protection circuit - stock 0.25W MFRs will work better, without drift. Also stay with the matched resistors for R5, R6, R8, R9. For the 22uF electrolytic in the protection circuitry, a Russian Teflon is waaay overkill - a general-purpose 22uF Elna or Chemicon is just fine.
For the stuff in the signal path or LM318 bypass, your upgrades are probably worthwhile, but take care with the lead-lengths of some of the large axials. Long leads add to inductance as well as EMI/RFI.
40 mV output offset is OK, not great, but not too bad. 100 mV is a bit too high though. Check the values of your Allen-Bradleys closely - a few may have aged and drifted considerably from the nominal value. Also, if the 100k input shunt is an Allen-Bradley, there will probably be some hiss without the low-impedance source connected - the thermal noise in large carbon comps is within the threshold of audibility.
For the 220pF, I'd stick with Wima FKP2 or Evox CFR - both are film-foil, and sound excellent in a small (5 mm pitch) package.
BTW, if you've got so many extra Black Gates, mail them to me - I promise to take good care of them 🙂.
On a more serious note, Black Gates are not needed for the relay protection circuitry - in fact the slow break-in may cause sub-optimal relay operation for a while. You may want to replace it with stock 220uF Nichicon PW or Chemicon KY or similar, nothing fancy. Same goes for the Allen-Bradleys in the protection circuit - stock 0.25W MFRs will work better, without drift. Also stay with the matched resistors for R5, R6, R8, R9. For the 22uF electrolytic in the protection circuitry, a Russian Teflon is waaay overkill - a general-purpose 22uF Elna or Chemicon is just fine.
For the stuff in the signal path or LM318 bypass, your upgrades are probably worthwhile, but take care with the lead-lengths of some of the large axials. Long leads add to inductance as well as EMI/RFI.
40 mV output offset is OK, not great, but not too bad. 100 mV is a bit too high though. Check the values of your Allen-Bradleys closely - a few may have aged and drifted considerably from the nominal value. Also, if the 100k input shunt is an Allen-Bradley, there will probably be some hiss without the low-impedance source connected - the thermal noise in large carbon comps is within the threshold of audibility.
For the 220pF, I'd stick with Wima FKP2 or Evox CFR - both are film-foil, and sound excellent in a small (5 mm pitch) package.
BTW, if you've got so many extra Black Gates, mail them to me - I promise to take good care of them 🙂.
Last edited:
You have taken the Myref to another level.Please post more about your impressions when it settles down 🙂
thanks weskoki, but it's siva and dario who deserve this recognition. i'm just a following their path with bigger tire tracks 😉
hehe sure, siva. but first give me 1000hrs to break them in for you 🙂
22uf (k73-16 pept) cap is probably the most excessive but even that location has an effect in sound, mainly in sound stage, as i noticed in the past from switching between different grades of nichicon of same voltage. so the choice was made to not leave any room to make me wonder 'what if'.
this is strange- after leaving it on last night, the relay problem is half cured. it now clicks on simultaneously on power up, though it still clicks off on different intervals.
dc reads 3.5mv for the bad channel and .7mv for the other.
and i just loove~ how quiet the amp is, how it maintains itself through all volume levels. even at the quietest it still lets all the detail and dynamics through, like a true class a amp.
late night listening is back on schedule, along with insomnia...
i'm sure all those involved know just what this amp's capable of so i wont delve into specifics, but I was rather surprised to find that even with all the cc resistors and blackgates, the amp still sounds dead neutral- that is, it just lets the music through with whatever colors and shapes they're designated with.
listening to a pod cast was a small revelation last night. i was treated to songs of all genre and each piece made me feel like i was listening to a different system, or rather, no system at all.
i could blabber on about the detail retrieval but to cut the long story short,
which voltage transformers should i get for 4ohm load? 😀
This has been discussed numerous times in the past but there doesn't seem to be an agreed number.
Last edited:
For a 4 ohm load a transformer with a 20-0-20 will be optimal. After rectification and filtering the DC voltage should be below 28-0-28 however I have found the sonics are best on 24-0-24 transformer secondary on a 8 ohm load.
i think we may have a serious contender against fkp2s for 150,220pf values. look at these new caps from kemet(rifa?)
http://www.kemet.com/kemet/web/homepage/kechome.nsf/file/PME271M%20Series/$file/KEM_F3011_PME271M_X2_275.pdf
paper in... oil?!
http://www.kemet.com/kemet/web/homepage/kechome.nsf/file/PME271M%20Series/$file/KEM_F3011_PME271M_X2_275.pdf
paper in... oil?!
Rifa PME271 has been around for a while - it's metallized (not foil) paper, for X2 mains applications. It's probably a bit more lossy than polypropylene.
Same quality and specs alternatives are Kemet PFR5 and Vishay KP1830.
Didn't tried PRF5, KP1830 are more neutral than FKP2 but a bit dry.
Probably I'll give KP1830 a second chanche in the final FE round-up.
Didn't tried PRF5, KP1830 are more neutral than FKP2 but a bit dry.
Probably I'll give KP1830 a second chanche in the final FE round-up.
My ReF is on the way
I started today to build my own MyRef amplifier. I used Rudi's pcb layout and used the premium BOM 1.5 with some adjustments according to Mouser's stock.
As they don't have ELNA RJH on stock for C9 i ordered a Nichicon Muse ES wich i discovered is non polar (or bipolar). It still can be used in the C9 position as they are nonpolar?
I've ordered some ELNA RJH from Ebay but they will arrive very slow and i'm not sure they are original or fake.
UES1H221MHM Nichicon Aluminum Electrolytic Capacitors - Leaded
I started today to build my own MyRef amplifier. I used Rudi's pcb layout and used the premium BOM 1.5 with some adjustments according to Mouser's stock.
As they don't have ELNA RJH on stock for C9 i ordered a Nichicon Muse ES wich i discovered is non polar (or bipolar). It still can be used in the C9 position as they are nonpolar?
I've ordered some ELNA RJH from Ebay but they will arrive very slow and i'm not sure they are original or fake.
UES1H221MHM Nichicon Aluminum Electrolytic Capacitors - Leaded
Attachments
Last edited:
Sure, they can be used.
But probably Nichicon FG (also available from Mouser) are a better choice.
I don't think... they're so cheap there's no reason to fake them.
What is the recommended value for the volume potentiometer ?
One channel from MyRef is running since few minutes ago from the first start.
DC on the output is about 0.2mV.
I cannot say too much about sonics from one channel.
One channel from MyRef is running since few minutes ago from the first start.
DC on the output is about 0.2mV.
I cannot say too much about sonics from one channel.
In my test environment the bipolar capacitor Nichicon Muse FG sounds noticeably better than Elna RJH in C9 position.
You're right.
The Elna RJH sounds better than Panny FM but, so far, the best cap after a Black Gate for that position is a Nichicon FG.
BTW your bipolar is Nichicon ES 😉
After I've refined the BOM for the Fremen Edition I'll also release an updated BOM for the Rev C which will probably include:
C6, C11 Nichicon FG 100uF 50V
C9 Nichicon FG 220uF 63V
R13 Caddock MK132V 100K
R10 Riken 390R
Last edited:
You are right is ES not FG. I'm so mad that i didn't ordered some FG's when i ordered from Mouser. Now it's late as the shipping rates are so high.
But i've found locally some Black Gate, they say Standard http://64.92.125.19/~audioalc/amplif/cond/cond.htm
Maybe would be a good choice also.
But i've found locally some Black Gate, they say Standard http://64.92.125.19/~audioalc/amplif/cond/cond.htm
Maybe would be a good choice also.
Last edited:
would any of the resistors in the signal path have an adverse effect on stereo separation if they're not matched to 1%?
I seem to have lost somewhat of that precision imaging after reflowing the cc resistors several times.
I fear it's due to their values drifting...
I seem to have lost somewhat of that precision imaging after reflowing the cc resistors several times.
I fear it's due to their values drifting...
haha time to dig up your old bom, then 😉
are all the locations marked 1% necessary for stereo matching?
edit: oh what the heck. caddock all the way 😀
are all the locations marked 1% necessary for stereo matching?
edit: oh what the heck. caddock all the way 😀
Last edited: