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Paradise phono stage build

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I've just aquired a pair of boards and components to buid a Paradise phono stage, it will be 3 boxes and have a dual mono psu. It came to my attention when Vlad suggested it looked like a good circuit, I didn't realise it meant matching transistors to 1% hfe output!

Looks like I'll be buying more transistors (1000 plus) and be spending lots of time matching. What meter would I need to measure this?

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Congratulations on acquiring the finest phonostage I have heard :). I'm not sure how you managed to miss the whole transistor matching issue though as there is a massive Paradise thread on the DIY Audio forum (from whence it came), a large thread in the DIY room of the pfm forum and a large thread on my own forum

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I use a Peak Electronics tester but don't know whether it would be accurate enough for your purpose

http://www.peakelec.co.uk/acatalog/jz_dca55.html

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I'm pretty sure that's what a friend used to build his, mine and a number of others - I'll check with him though. What I do know is that you have to be careful about the temperature when measuring them though - even holding them in your fingers warms them up enough to significantly alter the measured value.

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Yes temperature can affect measurements depending on the type of semiconductor. Germanium transistors (which I have used a lot in guitar effects) are particularly bad and drift around by as much as 10% depending on temperature and day of week and sunspot activity ;-). 1% test is pretty tight and may only be achievable by building a custom measurement circuit with precision resistors, voltage source and meter.

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I didn't miss it Mark, the kit I bought included 250 of each type and my reading suggests buying much larger quantities to match from. I was hinting that I'm not looking forward to this part of the build that's all.

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I just worded the OP badly, it reads as if I didn't realise and it was meant to read I didn't realise when Vlad first suggested it.

Is it Simon that did the matching for you Mark as I'm in contact with him via DIYA and was going to ask him which meter he uses....

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I understand - the whole matching bit is a PITA (though I didn't do any). I think the original requirement was selection within 5% but Si did our builds to better than 1% (yes, Si did the circuit build) and he did have to buy a lot more than 250. I'll probably see him tonight - I'll ask. Worth contacting him though as he may have spare components.

I should add that it is worth persevering with this build as it really does sound outstandingly good :).

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I'm still yet to hear one Mark. What have you compared it with?

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Any update?

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I decided not to go ahead with the build and sold the kit on. built a Salas simple folded Phono stage instead

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I have bought an unwanted group buy for the Paradise off a German owner. It's quite a project. I'll start with the pre-regulator and then very carefully assemble the regulator/amp boards after checking the gain of the relevant transistors with my Peak DCA 55. The seller told me they are closely matched. Hopefully I can call for assistance on the diy-audio forum if I get into trouble. I have the Pearl 2 currently which is good. I think the Paradise is possibly one the best performing phono amplifiers that you can build if it's assembled correctly. 

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Postscript - I realised that the Peak DCA 55 wasn't the best tool for the job. The hFE/voltage characteristics are different for the PNP and NPN transistors. Although the design is quite forgiving of mismatch, the best performance comes from closely matched gain in particular circuit locations. The DCA Pro can measure at 9V which is closer to the operating voltage.

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