Site updated
I have updated my site with all full schematics, Gerbers, descriptions, pictures and construction details for HPS 1.0, HPS 2.0 and HPS 3.1
www.synaesthesia.ca
Measurement results and listening tests/conclusions to follow soon.
If you plan to build any of these phono preamps, good luck! If you think there's anything missing, let me know...
I have updated my site with all full schematics, Gerbers, descriptions, pictures and construction details for HPS 1.0, HPS 2.0 and HPS 3.1
www.synaesthesia.ca
Measurement results and listening tests/conclusions to follow soon.
If you plan to build any of these phono preamps, good luck! If you think there's anything missing, let me know...
Hi!
I guess I will blankley not be able to come up with something better so I decided to build the HPS 3.1. I know there is the HPS 4 but I have the FETs and I definitly like the fact that it is virtually impossible to fry my cart(s) if something goes seriously wrong.
I have some questions, though. I can't read the gerbers, what is the software they are made with? What will the factory need to read them?
I hope they are predrilled as well then?
If someone has a pair of boards in spare I would certainly be happy to buy some.
The board's photos are good, I hope they will get me through the stuffing of the board.
What are other options are there for the regulator mosfets, will I get by with say IRF610/IRF9610 which I already have?
Is someone aware of a german supplier for the opa552 in the desired package? Even farnell or digikey seem to have problems to come up with it.
Thanks in advance,
Rüdiger
I guess I will blankley not be able to come up with something better so I decided to build the HPS 3.1. I know there is the HPS 4 but I have the FETs and I definitly like the fact that it is virtually impossible to fry my cart(s) if something goes seriously wrong.
I have some questions, though. I can't read the gerbers, what is the software they are made with? What will the factory need to read them?
I hope they are predrilled as well then?
If someone has a pair of boards in spare I would certainly be happy to buy some.
The board's photos are good, I hope they will get me through the stuffing of the board.
What are other options are there for the regulator mosfets, will I get by with say IRF610/IRF9610 which I already have?
Is someone aware of a german supplier for the opa552 in the desired package? Even farnell or digikey seem to have problems to come up with it.
Thanks in advance,
Rüdiger
- Pentalogix (free) will let you read and display the Gerbers.
- If you send the files to the factory, they will have no trouble reading them. The NC drill file is included.
- You need only one board, holds both channel and the power supplies.
- IRF610/IRF9610 will work perfectly fine.
- You can request TI on line for OPA552 in TO263 samples. They'll usually send you 5 pcs. no question asked.
- HPS 4.1 poses absolutely no risk to the cartridge, the input current can be trimmed down to under 50nA. I just had a debate about in the other thread, a number of famous MC pre's are using bipolar inputs, with input currents two order of magnitude larger than in HPS 4.1. They conveniently don't mention the input current in their glossy brochures, the customers are happily using them without knowing about. Otherwise, listening tests are showing a slight preference towards HPS 4.1
Good luck with the construction, and welcome to the club
Syn, thanks for your reply.
Did you check what happens at the input if one of the supply rails will fail? I once fried a cart with exactly that scenario, exposing it to 0.6V for about 24h.
With FETs, that wouldn't happen afaik.
It will be fun to build, I'm sure.
thanks for all your input,
Rüdiger
Did you check what happens at the input if one of the supply rails will fail? I once fried a cart with exactly that scenario, exposing it to 0.6V for about 24h.
With FETs, that wouldn't happen afaik.
It will be fun to build, I'm sure.
thanks for all your input,
Rüdiger
Syn, thanks for your reply.
Did you check what happens at the input if one of the supply rails will fail? I once fried a cart with exactly that scenario, exposing it to 0.6V for about 24h.
With FETs, that wouldn't happen afaik.
You'll have the same problem with JFETs. Only MOSFETs may protect you against such failures, but you can't use them in a low noise input stage.
Hi,
It seems that I'm in luck and someone will help me out with a board. So, if all works out smoothly I don't need to have any boards made for now.
Am I right to assume that R209-R212 and R214 as well as C209, C211 and C215 are the RIAA.-related parts and would benefit from matching? Which options does the board provide to reach the 2.7n-value for C209?
It would hurt to match R213 <--> R226 as well, I guess.
Thanks,
Rüdiger
It seems that I'm in luck and someone will help me out with a board. So, if all works out smoothly I don't need to have any boards made for now.
Am I right to assume that R209-R212 and R214 as well as C209, C211 and C215 are the RIAA.-related parts and would benefit from matching? Which options does the board provide to reach the 2.7n-value for C209?
It would hurt to match R213 <--> R226 as well, I guess.
Thanks,
Rüdiger
Resistors to match:
R209
R210
R211
R212
R214
R217
R218
Caps to match:
C209
C211
C215
C217
Note that R217/C215 are defining the Neumann 50KHz pole. You may want to skip C215 if you don't want to implement this pole.
I would suggest 1% components (or sorted accordingly) and better than 0.5% matching between channels. I though had problems in finding 1% polypropylene caps, so I end up with sorted 2% PPS (C211, C215, C217) and polypropylene (C209). Get 10 of each value and you'll have no problems in matching.
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