Thanks Mate, i keep on thinking all the output transistors are pin compatible so i just need to flip it around.
Quan
Hummmmmmmm
My Paradise is installed in the system and is playing music😀 But, there is hum, lots of hum🙁
Looking at the diagram I think I need to connect the mains earth coming in to the pre-reg to the chassis via a DDRC circuit and use this to provide a common for the ground rails of the PSUs and the tonearm earth wire to connect to. Does this sound about right? My TT has a DC motor so no mains connection to the deck. Any recommendations for the diodes for the DDRC? I'm presuming that they don't need to be anything special.
I make a rule of never reviewing, in detail, anything I've built for at least a few days so that my objectivity isn't affected by FMIW (f$*k me, it works!) syndrome but, even despite the hum this thing is quite special!
My Paradise is installed in the system and is playing music😀 But, there is hum, lots of hum🙁
Looking at the diagram I think I need to connect the mains earth coming in to the pre-reg to the chassis via a DDRC circuit and use this to provide a common for the ground rails of the PSUs and the tonearm earth wire to connect to. Does this sound about right? My TT has a DC motor so no mains connection to the deck. Any recommendations for the diodes for the DDRC? I'm presuming that they don't need to be anything special.
I make a rule of never reviewing, in detail, anything I've built for at least a few days so that my objectivity isn't affected by FMIW (f$*k me, it works!) syndrome but, even despite the hum this thing is quite special!
I've used 1930 before and nearly got caught out by that pin arrangement.
If you have the Calvin boards it gets a bit tricky as the 1930 ends up lying on its front. If you have enough room in the case you could have the heat sink standing up but that puts the heat near to the IP transistors.
I've used the ones specified in the build guide to keep things simple.
I’m about half way through my Rescue Paradise build (V2 obtained from someone without enough time to build) so buffer un-tried.
Good luck with the buffer I’ll be interested in your thoughts on the sound.
Hi guys, swapped the jfets around and also the output transistor. One channel -offset is now zero, the other channel is down to 16mV only with trimmer maxed out. 
.
Quan
.Quan
Paradise now grounded as per the above and the hum is gone. Even at full volume on the pre there's zero hum and a pretty low level of noise. Time for some weeks of serious listening now before adding the Calvin.
Thanks guys, for the many hours of design and all the time spent answering questions here. Definitely a design to be proud of.
By they way, regarding grounding - i'll try ground the tonearm directly to chassis, rather than mains - at least to me it seems more logic, since both are really a "case"/shield for the signal. And it seems to me bad having an "antenna" connected to common ground, if i have hum then i'll just change it. Will report back if this works when i get to that point.
Just need to buy a little cabling for the case and get more DIY time (ie getting baby to sleep early) and of course match 600pcs 337's more to get better matches - then i'll start building the PCB's 🙂
Just need to buy a little cabling for the case and get more DIY time (ie getting baby to sleep early) and of course match 600pcs 337's more to get better matches - then i'll start building the PCB's 🙂
Hi guys, swapped the jfets around and also the output transistor. One channel -offset is now zero, the other channel is down to 16mV only with trimmer maxed out.
Quan
At least things are moving.... Theoretically (well.....) with some JFETs, D and S can be swapped without problems, but that may not be true for these.
Could you please measure the Gate-Source voltages of the 4 JFETs?
Hi Alfred, the measured G-S voltages of the jfets are:
Q1 0.05V
Q2 2.028V
Q4 0.028V
Q5 2.008V
Quan
Q1 0.05V
Q2 2.028V
Q4 0.028V
Q5 2.008V
Quan
the low Vgs of Q1 & 4 confirm thay are baised close to but under the Idss.
The highish Vgs of Q2 & 5 confirm that your devices at running at very much less than Idss.
BTW,
Nchannel jFETs have a -ve Vgs. i.e. Voltage of g is more negative than voltage of s.
The highish Vgs of Q2 & 5 confirm that your devices at running at very much less than Idss.
BTW,
Nchannel jFETs have a -ve Vgs. i.e. Voltage of g is more negative than voltage of s.
yes, and that is on purpose, these voltages are fine. still, that doesnt explain the offset. Could you try and replace R8a (220 ohm) with a resistor of 560 Ohm?
Hi Guys,
have been on holidays for the last month. tried to catch up by reading all the posts yesterday.
so those are the questions left at my side related to use the CALVIN BUFFER with the PARADISE
1) CALVIN BUFFER:
The resistor R15 is optional, when used as a buffer for Paradise it should NOT
be inserted.
does this mean R15 should be connected by wire, or it should be left unexploited at all?
2) PARADISE BOARD:
One advice for new paradise builders: Don't solder the smd-caps in before you have tested the regulator and the riaa-amp.
WHY?
3) PARADISE BOARD:
PradiseBuilders #2969 About the Paradise PSU using Calvin buffers.
is this Post reffered to R104/R204 on the Paradise Board? or does it mean other 10Ohm Resistors anywhere else?
the BOM says 8R2 für those Resistors R104/204
thank you!
michael
have been on holidays for the last month. tried to catch up by reading all the posts yesterday.
so those are the questions left at my side related to use the CALVIN BUFFER with the PARADISE
1) CALVIN BUFFER:
The resistor R15 is optional, when used as a buffer for Paradise it should NOT
be inserted.
does this mean R15 should be connected by wire, or it should be left unexploited at all?
2) PARADISE BOARD:
One advice for new paradise builders: Don't solder the smd-caps in before you have tested the regulator and the riaa-amp.
WHY?
3) PARADISE BOARD:
PradiseBuilders #2969 About the Paradise PSU using Calvin buffers.
is this Post reffered to R104/R204 on the Paradise Board? or does it mean other 10Ohm Resistors anywhere else?
the BOM says 8R2 für those Resistors R104/204
thank you!
michael
Ad 2)
These smd caps caused quite often some troubles as a solder-short underneath the cap can't be seen. When the regulator and the amp works before you solder them in and after no more you know directly what's wrong (and what to do^^)
cheers
galac
These smd caps caused quite often some troubles as a solder-short underneath the cap can't be seen. When the regulator and the amp works before you solder them in and after no more you know directly what's wrong (and what to do^^)
cheers
galac
R15 should not be inserted, do NOT add a link as this will short the output from the Paradise, just leave the space empty🙂
I think the reason for this is that the soldering of the SMD caps can be tricky and had led to a few solder shorts that proved hard to troubleshoot. Personally I decided to put them in right at the beginning and test for shorts with a meter to be sure there were no issues before going any further.
This is referring to the 10Ohm resistors in the shunt on the main Paradise board (in the PSU section). The shunt is designed to consume around 30mA to work correctly, leaving around 80mA available to the amp. When the Calvin is added the amp now needs around 110mA so the CCS now has insufficient capacity. Changing the 10R resistors to 7R5 increases the CCS current to around 140mA so it can now power the amp and Calvin but still have enough left for itself.