Many thanks to all concerned with this mammoth group buy my parts arrived this morning.Time to start stuffing the boards.
Half of mine arrived this morning. Typical it's always me.... lol.
Frankly given the number of parts and size of the group buy I'm still amazed how well it all went, congrats and thanks to all involved.
Frankly given the number of parts and size of the group buy I'm still amazed how well it all went, congrats and thanks to all involved.
I am a happy man my package came today,,well done boys lots of hard and tedious work thank you 🙂 regards john
Finished stuffing the boards and currently checking dc op points. As usual i jump into these GBs at the frenzy of the moment and only get to do some reading afterwards 🙂
Does anyone have an idea if converting this to a FET input is at all possible? Even at the expense of major surgery? The idea of an even small offset does not fill my heart with joy. Whilst it may not kill the cart, it will very likely cause some permanent magnetisation. What's even worse is that the trimming pot makes a mockery of my Shinkoh loading resistors, being effectively in parallel.
Sorry if this has already been discussed in the monumental MPP thread.
Does anyone have an idea if converting this to a FET input is at all possible? Even at the expense of major surgery? The idea of an even small offset does not fill my heart with joy. Whilst it may not kill the cart, it will very likely cause some permanent magnetisation. What's even worse is that the trimming pot makes a mockery of my Shinkoh loading resistors, being effectively in parallel.
Sorry if this has already been discussed in the monumental MPP thread.
Trimming has being discussed. You need a dummy resistor in the value of the DC resistance of your cartridge parallel to the loading resistor. Then trim the DC, take out the dummy resistor and connect the cartridge.
Yes, it can be transferred to Fet with major surgery but i would not recommend to do this with the Paradise boards.
Yes, it can be transferred to Fet with major surgery but i would not recommend to do this with the Paradise boards.
Thanks for the answer Joachim. Yes, i am aware of the trimming procedure. A major pain with multiple carts.
If at some stage you decide to publish an alternative take of the front end with K389/J109 per example i will be very grateful. And no doubt, so will be others.
If at some stage you decide to publish an alternative take of the front end with K389/J109 per example i will be very grateful. And no doubt, so will be others.
I have published MC input stages with J-Fets on the MPP thread.
One of the more successful ones was build by Sampler, our friend from Litunia.
When i find the time i will search for the schematic.
One of the more successful ones was build by Sampler, our friend from Litunia.
When i find the time i will search for the schematic.
The 25-40 is HFe groups.
The work here has shown that the groups are not that well defined.. So if you can find good matches the groups are meaningless.
The work here has shown that the groups are not that well defined.. So if you can find good matches the groups are meaningless.
And you can pack the lower Hfe ones in the mirrors without a problem.
They even work in the input stage although input DC offset will be a bit higher in proportion to the loss of Hfe. Can be dealt with just fine with the offset trim.
The only problem that remains is when you swap cartridges quite often that have a big difference in DC impedance. To fry a cartridge is unlikely though.
They even work in the input stage although input DC offset will be a bit higher in proportion to the loss of Hfe. Can be dealt with just fine with the offset trim.
The only problem that remains is when you swap cartridges quite often that have a big difference in DC impedance. To fry a cartridge is unlikely though.
Unforunatly I bought for the R2 and R21-R28 (33 Ohm) and for the R107, R108 (47 Ohm) Vishay RN55C 1/10W is it enoght?
The RN are military rated so in fact they can stand more wattage. I think they will do the job just fine.
