Interesting spectra, I was wondering about using something like this for ULF geoscience. There are people that use HUGE magnetic pickups and bipolar inputs, but I saw a guy that used a FET and simple earth's E field sampler to get better ULF spectra.
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...
I like the third version a lot, from the servo to the low impedance network. I believe the FC'ed complementary input stage will sound good.
Isn't the link called 'HPS3.0 schematic' not the version 3.1 really?
Rüdiger
Isn't the link called 'HPS3.0 schematic' not the version 3.1 really?
Rüdiger
Onvinyl said:
Yes, the page titles got a little messed up (I'll fix it ASAP). No, everything in the content is HPS 3.1
Thanks for writing all the details - very interesting reading!
Have fun, Hannes
PS: considering your enthusiasm for low-distortion I'm a little surprised you use a belt-drive turntable - wouldn't some japanese directdrive be more to your liking 😀 ?
Have fun, Hannes
PS: considering your enthusiasm for low-distortion I'm a little surprised you use a belt-drive turntable - wouldn't some japanese directdrive be more to your liking 😀 ?
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
Last edited:
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.
I'm always looking for feedback on my designs, so pictures, comments, etc... are always welcomed.
Hi,
Jacco, If no-one would have a spare board for me, I'm looking for a board manufacturer tomorrow. I will contact you as soon I know more.
Syn, as soon as the thing is running I'll make some photos and write some lines.
Rüdiger
Jacco, If no-one would have a spare board for me, I'm looking for a board manufacturer tomorrow. I will contact you as soon I know more.
Syn, as soon as the thing is running I'll make some photos and write some lines.
Rüdiger
Re. OPA532 / boards
To Syn08: are you using the DIP-8 or the DDPAK-7 version, me thought I saw the latter ?
To Onvinyl: RS-Online DE carries them. Also, it does not do any harm if you tell us how much the boards are in Germany, I might be interested in a PCB if the price is OK.
To Syn08: are you using the DIP-8 or the DDPAK-7 version, me thought I saw the latter ?
To Onvinyl: RS-Online DE carries them. Also, it does not do any harm if you tell us how much the boards are in Germany, I might be interested in a PCB if the price is OK.
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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