diyAudio group buy Paradise R3 phono stage boards

[pitfisch]

Thxalot.
U2 !

 

[337alant]

Hi Alan,
i am the man who was betrayed by Block.
The parts were picked properly in terms of rating.
Despite the fact Block is a well known german
manufacturer and i used some of them stuff in the
past without any issue.
Those Trafos are just crap !
Sadly, there is no hum-rating in the spec-sheets,
not even mentioned,
so there is no legal chance to get the money back.
If you have any questions in terms of translation....

Cheers
peter

Hi Peter
Thanks for that information and your right there is no real way of knowing by the spec and its very frustrating when you have went to all the time and expence of getting what you belive is the ideal transformer only to find its buzzing.
My house mains is 250VAC and this has upset quite a few transformers Ive tried but I havent had any problems with torroids that I have had made specifically for 240-250vac from Cantabury windings they are dead silent and run cool
I have 3 of these transformers and they are also good, I use one in my pre amp, but I dont know if it fits the foot print in the pre reg boards?
http://rover.ebay.com/rover/1/705-5...0001&campid=5338728743&icep_item=371020315809
http://www.talema-nuvotem.com/ Talema do similar but not sure if they are as good could be worth talking to them about their Block transformers ?
I bought 2 other transformers from China for a DAC and they buzzed like crazy and got hot so i binned them immediately

Alan

 

[grazie]

Assuming I can show interest in the transformer group buy in English, can someone please post a link to the correct thread on http://www.analog-forum.de?

 

[Markus S]

http://www.analog-forum.de/wbboard/...paradise-phono-stage/index26.html#post1344340

The organiser is miepa who is on diyaudio as well, http://www.diyaudio.com/forums/members/miepa.html , so perhaps you can contact him there and don't have to register to analog-forum.de

 

[grazie]

Thanks Markus.

 

[grazie]

I contacted miepa. The current status is that the group buy is at 42. When the interest hits 50 the group buy will close. To join the group, you need an account on diyAudio.com and you'll need to pay for the items plus delivery in advance as per usual. The group is going with the Tauscher (Exchanger) transformer and the price will be €10.45 plus VAT and delivery, if they get to 50 units.

 

[shoom]

Hi All

I popped some Cree SIC diodes into my Paradise DIY etch PSU a week or so ago and IMHO they sound better than the quad speeds that I used previously.

i ended up using these

http://uk.mouser.com/ProductDetail/...=sGAEpiMZZMtQ8nqTKtFS/Cwtife2N73IBkBxIS6S7m8=

check out the zero forward and revese recovery voltage in the data sheet. Now that's what i call low switching noise.

They sound clearer with an even bigger soundstage and smoother to my ears in my set up.

I needed the Hackercap board for the other build I popped in some Mundorf Mlitics from my parts box as the last cap when i swapped boards. I’m not sure why or if I’m hearing things but they also made some difference to the bass and overall richness of the sound IMHO.

All in all a nice bump up in SQ especially with the Cree in.

 

[df_genius]

Mine has been progressing slowly. A couple of days ago I had two more pairs of PCB's arrive (might as well, you never know when you might need them, it is not a good feeling when you realise you missed out on a great group buy), and I also ordered 300 more BC337 as I wasn't happy with the HFE values I had to match up with. I ordered 200 from CPC and 100 from a trusted ebay seller. The CPC batch were very good - most were between 350 and 400 which meant I could easily match up sets for all six boards. It can be a tedious job (I ended up measuring over 900 transistors in total), I find the easiest way is to tape them to A4 paper writing the value down and then input that into a spreadsheet (noting the page number and the row the transistor was on), you can then sort by hfe values. Also worth noting is the CPC price is £6 delievered for 100 which I think is pretty cheap.

I've got a few other bits to finish off so it will probably be a week or two before I can make much real progress with the Paradise but it should be completed in the not too distant future

 

[shoom]

Hi DF

Good work and great tip for keeping tabs on transistors.

I usually use a strip of masking tape with the HFE value written on it folded around the transistor legs to keep matches together but your way looks better.

That transistor matching left my head in a spin but believe me its well worth the effort.

The Paradise is superb.and with the matching done it all comes together quickly.

Keep us posted.

 

[df_genius]

What is the consensus on the best method of filtering before the regs? I don't have the pre-reg PCB's, but plan on using decent passive filtering. I have 12 Panasonic 3300uF 35V (so 3 for each rail) and am planning on using a Nover audio grade 6800uF as the last cap before the reg. So I can use CRCRCRC or CLCLCLC, or even a mix of R and L as required. What value of L is a good starting point? Transformers are a pair of 30VA potted toroids, 18-0-18.

 

[shoom]

Hi DF

I think that most people here have used either hackercap boards in CLCLC configuration or the Paradise pre reg boards. I now have a self-etched Hackercap CLCLC and it sounds pretty darn good to my ears but I’ve not compared it to the pre reg set up so maybe Simon has more experience with that.

I’d say that low noise and low impedance would be the key for this sort of circuit so I’d be aiming for that first. It’s a great sounding phono stage and well worth the effort of getting the pre reg smoothing as good as it can be.

For the above reasons I’d opt for CLCLC and not be using CR type set ups.

Sorry for not giving a definitive answer bet that’s where I am at the moment.

That’s my take but others may have a different one.

 

[df_genius]

This is what my PCB's look like. The transistor group gains are matched between channels as well as their complementary groups. RIAA caps are also matched to within three figures. I only have one set of heatsinks and am still waiting on some final resistors but the first pair aren't far off. Next job is to measure/match the LEDs.

https://drive.google.com/file/d/0B5mNigTsST6ZQmFEdmxHSDRuYVU/edit?usp=sharing

 

[shoom]

looking good

 

[337alant]

I have just replaced the power supply transformers due to an annoying buzz from mine and excessive heat at the shunt regs from the supply voltage being unnecessarily high.
I replaced them with a couple of 18-0-18v encapsulated torroidal from ebay these are dead silent and now the heat sinks are only hand warm
https://www.flickr.com/photos/69508926@N05/14087827194/in/photostream/
https://www.flickr.com/photos/69508926@N05/14087342685/in/photostream/

I also did the DDCR thing under my Garrard and at the Paradise input and had to lift the ground connection in my pre amp but result is I now also have complete silence with the pre amp flat out, so another result but I think with this grounding scheme comes a slight loss in transparency and air?, anyone else notice that?.

 

[YNWOAN]

Not in this specific context, but in the past I have found that subtle alterations in grounding can have that effect.

 

[shoom]

Hi Alan

I’ve done my DDRC in exactly the same way as outlined in the build guide and it’s also dead quiet but without having to lift any of my pre’s grounds.

Here is Alfred’s method and the way that I have my Paradise

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And for the PSU box

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sorry for my crude sketches but it may help.

 

[df_genius]

I've got my first board fully working. I had to remove all the power transistors and heatsink and add insulation pads to the bipolars as well as the FETs (from looking at the silkscreen on the PCB just the FETs need insulating). It's all working properly so far, I do get some oscillation (a couple of hundred mV at a few Mhz) so will be adding the compensation caps (my first pair are R2 PCB's). However the supply I have been using is my LM317/337 "testbench" setup so they could easily have insufficient bandwidth for the regs to work properly.

DC offset is around 300mV, but it does drift around a bit as well, so additional work is needed. Alas, it looks like I need to add capacitors to the output as my pre-amp is DC coupled and DC needs to be as low as possible. I'll add some pics later when the second board is running.

What regulator FETs are people using? I whipped out the J310's before I powered them up and replaced with K170's of around 7mA idss. Supposedly one of the better ones to use - just be careful of the pinout. I also have the Calvin buffers to add but am waiting on my PN4391 ordered from the link below - they seem very reasonable price-wise although mine were ordered last week and haven't arrived yet)

http://www.futurlec.com/Transistors/PN4391pr.shtml

 

[shoom]

Hi DF

Nice work.

Is that DC offset measured after a full warm up with the lid on? The front end is VERY sensitive to temperature changes and if you are measuring outside of a case I could affect your readings.

 

[sq225917]

I've built eight pairs of Paradise now for various peeps and have my ingredients list pretty well sorted. I added the Calvin buffers into the mix over the weekend and am very happy with them. With OPA627 in place in the servo and the Calvin's fitted I'm now essentially at 0.0mv DC offset on the output- result.

My only bug bear was noisy traffos in the group buy parts. I need to replace these for one punter.

 

[flatpopely]

I may be calling on you soon...........