That capacitor model is as you described.
An externally hosted image should be here but it was not working when we last tested it.
Alps is smooth rotating with good log taper (volume rises intuitively louder as you turn it up). Its not harsh but not that transparent or focused. For better results you would need to spend on a good stepped attenuator. There are cheap SMD resistor stepped ones on ebay for around $20 also. They sound good but their long term reliability has been questioned some times.
Log. Linear will open up the volume weirdly fast for the human ear loudness perception curve. The Obbligato MKP oil are excellent value for money and they come in big uF. Plus they are not harsh. Can be mounted sturdily with a bracket. There are step ups from there, including their own gold line claimed to be better which is still fairly well priced. There are many much more expensive choices of course. Read around, ask members. We use the DCB1 as DC coupled by majority.
Hi Salas and fellow Mezmerize builders. My first post here, so please excuse any duplication of comments.
After what seems like months of reading through the various Mezmerize/DCB1 threads I finally ordered the pcb, promptly delivered to me here in the UK, components sourced from the likes of Mouser, Farnell and eBay, hours of matching the 2sk170s and LEDs and eaarlier this week I completed assembly of the Mezmerize. Powered up and everything worked first time, but despite careful matching of the LED strings the rail voltages were +10.92 and -10.17, also the strings of five LEDs were slightly different brightness. Measuring the volt drop across the 10ohm resistor at the base of the string showed that the negative supply string wewre carrying 70mA, whilst the positive supply string carried 171mA. A bit of investigation and I noticed that the schematics show that the 2sk170s at the base of each string are configured differently. For a normal CCS configuration gate and drain are connected together, however the schematic shows the 2sk170 CCS for the positive LED string with gate and source connected together, thus not working as a CCS. The pcb is also configured this way. I can't find any reference to this anywhere in te various threads, has any one else noticed this?
Anyway, a slight modification to the pcb and now I have the CCS working correctly.
After about 6 hours of "burning in", current in each string of 5 is now 6.8mA, the strings of 3 have 8.7mA, the power rails +10.18 -10.14, and the output offsets are 0.5 & 0.1mV. I'm very pleased with this!
Next step is to add the Lighter Note attenuator that I've ordered from Uriah Dailey and get on to listening to it. I shall try to get a listen before I add the Lighter Note and report further.
Meanwhile, Thanks to Salas, crt, Teabag all all other contributors for their contributions to the Mezmerize.
After what seems like months of reading through the various Mezmerize/DCB1 threads I finally ordered the pcb, promptly delivered to me here in the UK, components sourced from the likes of Mouser, Farnell and eBay, hours of matching the 2sk170s and LEDs and eaarlier this week I completed assembly of the Mezmerize. Powered up and everything worked first time, but despite careful matching of the LED strings the rail voltages were +10.92 and -10.17, also the strings of five LEDs were slightly different brightness. Measuring the volt drop across the 10ohm resistor at the base of the string showed that the negative supply string wewre carrying 70mA, whilst the positive supply string carried 171mA. A bit of investigation and I noticed that the schematics show that the 2sk170s at the base of each string are configured differently. For a normal CCS configuration gate and drain are connected together, however the schematic shows the 2sk170 CCS for the positive LED string with gate and source connected together, thus not working as a CCS. The pcb is also configured this way. I can't find any reference to this anywhere in te various threads, has any one else noticed this?
Anyway, a slight modification to the pcb and now I have the CCS working correctly.
After about 6 hours of "burning in", current in each string of 5 is now 6.8mA, the strings of 3 have 8.7mA, the power rails +10.18 -10.14, and the output offsets are 0.5 & 0.1mV. I'm very pleased with this!
Next step is to add the Lighter Note attenuator that I've ordered from Uriah Dailey and get on to listening to it. I shall try to get a listen before I add the Lighter Note and report further.
Meanwhile, Thanks to Salas, crt, Teabag all all other contributors for their contributions to the Mezmerize.
Hi, maybe 7.1mA and 17.1mA? its been discussed some times before but its naturally difficult to locate over an old long thread. The sinks for the 5strong LED groups are configured as you found on PCB not by error but on purpose. Its not on the Hypnotize HR though. That was to add some more 2nd harmonic in the Mez as it was designed to run at only 60-70mA and it was found worthwhile tonally. It creates a steady difference in rails also that helps the not very well matched audio JFET pairs to show less offset when tried around in each pair. Its easy to run it in ''orthodox'' mode as you found, and it has been described there in the old black non HR Hypno alternative use as general PSU. They show a slight subjective difference between orthodox and heretic. Congratulations for your build, photos are always welcome. For how much current you set the rails CCS? Let us know how you liked it when you will put it to service. Thanks and regards.
Salas, Thanks for your response.
You are correct the current was 7 & 17.1mA, I quoted the volt drop, but noted it as current!
Thanks for the explanation regarding the different loads in the led strings. I had picked up on the difference in rail voltages to add more 2nd harmonic, but thought that referred to earlier versions. I'll have a listen to see which I prefer.
For now I have set the rails CCS at the "normal" 60mA with 2 x 68R. As soon as I have mounted the MOSFETS on reasonable size heatsinks I shall increase the current to perhaps 120mA or so.
Photos, will of course, follow.
You are correct the current was 7 & 17.1mA, I quoted the volt drop, but noted it as current!
Thanks for the explanation regarding the different loads in the led strings. I had picked up on the difference in rail voltages to add more 2nd harmonic, but thought that referred to earlier versions. I'll have a listen to see which I prefer.
For now I have set the rails CCS at the "normal" 60mA with 2 x 68R. As soon as I have mounted the MOSFETS on reasonable size heatsinks I shall increase the current to perhaps 120mA or so.
Photos, will of course, follow.
Hi all,
I was doing some checks prior to firing up my Mesmerize and I noticed that the outputs are shorted to ground. It seems as though the relay on the outputs is closed. The three inner sets of pins on the relay have continuity. None of the input relays are like this. Is this normal? I've gone over the board looking for shorts and can't find any.
Thanks,
Mark
I was doing some checks prior to firing up my Mesmerize and I noticed that the outputs are shorted to ground. It seems as though the relay on the outputs is closed. The three inner sets of pins on the relay have continuity. None of the input relays are like this. Is this normal? I've gone over the board looking for shorts and can't find any.
Thanks,
Mark
Matched 2SK170-BL pairs
Hi Guys, I've been a forum member for about a year and a half but have been a bit low profile so far.
I've just finished a Gainclone using boards from Brian GT and have now embarked on a Mezmerise. Can anyone point me to a UK/EU source for matched 2SK170-BL pairs? (Andrew T maybe?). Thanks.
Hi Guys, I've been a forum member for about a year and a half but have been a bit low profile so far.
I've just finished a Gainclone using boards from Brian GT and have now embarked on a Mezmerise. Can anyone point me to a UK/EU source for matched 2SK170-BL pairs? (Andrew T maybe?). Thanks.
AndrewT supplied me with sets for the DCB1 a while back but whether he still does I'm not sure.Best bet would be to pm him.
Failing that Spencer is a good guy to deal with and supplies well matched fets and delivery is usually pretty quick.
Store | FET Audio
Failing that Spencer is a good guy to deal with and supplies well matched fets and delivery is usually pretty quick.
Store | FET Audio
Looking to regulate a class "A" power amp, F5
I was wondering about using IRFP044N for the positive regulator and doing an upside down positive reg for the negative side. I want to use the IRFP044N due to the current they pass or should I just do a cap multiplier like Juma uses?
+/-+/-
Rush
I was wondering about using IRFP044N for the positive regulator and doing an upside down positive reg for the negative side. I want to use the IRFP044N due to the current they pass or should I just do a cap multiplier like Juma uses?
+/-+/-
Rush
I'm using an R-Core transformer from diyclub and am wondering how the secondaries should be twisted together, if at all.
The model I have is R26-34 with 9V and 15V secondaries. Each secondary has four wires, 2x blue and 2x grey for 15V. As I understand it I should connect one blue and one grey wire together to create a 0V center tap. Should I twist these together? Or do I twist each color seperately and simply connect the blue and grey together at the PCB?
--------- 1x blue
xxxxxxx 1x blue + 1x grey
--------- 1x grey
xxxxxxx 2x blue
>1x blue + 1x grey
xxxxxxx 2x grey
Also, for the primaries, is it beneficial to twist the hot and neutral wire together?
The model I have is R26-34 with 9V and 15V secondaries. Each secondary has four wires, 2x blue and 2x grey for 15V. As I understand it I should connect one blue and one grey wire together to create a 0V center tap. Should I twist these together? Or do I twist each color seperately and simply connect the blue and grey together at the PCB?
--------- 1x blue
xxxxxxx 1x blue + 1x grey
--------- 1x grey
xxxxxxx 2x blue
>1x blue + 1x grey
xxxxxxx 2x grey
Also, for the primaries, is it beneficial to twist the hot and neutral wire together?