Carlos,
The specified capacitance is 150-300 pF. It means that in addition to the cable capacitance, a little bit of extra is desirable.
The Emerald by default has zero added input capacitance. The SwitchBoard by default adds options for 100 pF and 200 pF. Figuring the phono cable provides about 100 pF, that gives you the option of 100, 200 and 300 pF. This provides flexibility to try different values within the guide range to see which works best.
Finer adjustment is not required in my opinion. But, if you want to add a specific value just add the component across the input of the Emerald.
The specified capacitance is 150-300 pF. It means that in addition to the cable capacitance, a little bit of extra is desirable.
The Emerald by default has zero added input capacitance. The SwitchBoard by default adds options for 100 pF and 200 pF. Figuring the phono cable provides about 100 pF, that gives you the option of 100, 200 and 300 pF. This provides flexibility to try different values within the guide range to see which works best.
Finer adjustment is not required in my opinion. But, if you want to add a specific value just add the component across the input of the Emerald.
Of interest to a passing bat perhaps ?
Changed the character of the op amp rather ..
Finally got around to building my set of Emeralds. Easy to build and works like a charm for my MM element on Rega turntable. Started off with OPA134's i had lying around but finally settled on OPA627 for IC1 and LME49710 for IC2 which to me sounds perfect. Also noticed that C3 has the biggest impact on sound so experimented here as well, WIMA MKP was OK, Audyn also fine but the best for me turned out to be a Mundorf MKP 2,2uF.
Next is finding a nice enclosure...
Next is finding a nice enclosure...
Is there anyone building these and maybe would sell one ? Please message me with a price. I’ve been trying to do some Soldering and my hands are not what they used to be. As I have severe arthritis and carpal tunnel syndrome. My hands just are not sturdy nor can I hold onto the iron for more than two or three minutes at a time without going into a lot of pain. So if someone would help me out that would be wonderful. I also am in the states, in Florida
I hope someone here can help you out. I have occasionally sold pre-build boards but not fully assembled units.
You can also get one from Audio Wise.
You can also get one from Audio Wise.
Another emerald lives!
Thanks to very clear instructions and excellently put together kits, this was a straightforward build. It was made a bit easier for me because I had built phonoclones and VSPS before, so I had a power supply and case ready to go. Its dual mono, and worked perfectly on first power up. The plan is to leave it running for a few days at least to settle down (I seem to remember the phonoclone needing a few days to settle down completely). Anyway, it sounds good right out of the box.
I'll try the cap across R5 that I read about a few posts back and will report back. The other thing I might look at is changing out the toroids for R-cores.....I haven't read the thread end to end, but has anyone else done that?
Thanks again Richard for the kit and all the background work.
Thanks to very clear instructions and excellently put together kits, this was a straightforward build. It was made a bit easier for me because I had built phonoclones and VSPS before, so I had a power supply and case ready to go. Its dual mono, and worked perfectly on first power up. The plan is to leave it running for a few days at least to settle down (I seem to remember the phonoclone needing a few days to settle down completely). Anyway, it sounds good right out of the box.
I'll try the cap across R5 that I read about a few posts back and will report back. The other thing I might look at is changing out the toroids for R-cores.....I haven't read the thread end to end, but has anyone else done that?
Thanks again Richard for the kit and all the background work.
Attachments
15 v DC output even better.. Than 12.. Since you have 2x 15v,
Richard posted the resistor change on that,
35 v no issue won't increase the heat much
Hi Fran,
Thanks for posting your build photo. As noted you can use 15 VAC secondaries with 35 V caps. No head increase that matters. I don't think there's a material difference betwen R-core and toroids. I use them interchangeably. R-core with electrostatic screen are easy to get off ebay, Triad VPM are nice toroids.
Please do try that R5 mod. I'm very keen to get a second opinion on it.
Richard
Thanks for posting your build photo. As noted you can use 15 VAC secondaries with 35 V caps. No head increase that matters. I don't think there's a material difference betwen R-core and toroids. I use them interchangeably. R-core with electrostatic screen are easy to get off ebay, Triad VPM are nice toroids.
Please do try that R5 mod. I'm very keen to get a second opinion on it.
Richard
Will do. I did search through the parts stash and the smallest cap I could find were some 47pf mica. I know that would drop the frequency cutoff a bit more, but not that much?
Will try it tonight.
Fyi, certainly I reckon that the r-core transformers@15v gave a deeper bass response (that was last night's experiment). However I have to balance that by saying the unit had burnt in for another 24hrs compared to first listen.
Will try it tonight.
Fyi, certainly I reckon that the r-core transformers@15v gave a deeper bass response (that was last night's experiment). However I have to balance that by saying the unit had burnt in for another 24hrs compared to first listen.
Just an update for the thread:
R-core 15v transformers: I really think I got a boost n bass response when I swapped over to these transformers. Now there are a few things to bear in mind. First off, the R-cores are Selectronic from France, secondly the secondary voltage is 15v, so I had to go to 35v caps for the input, and the only ones I had were 1500uf, so this is a little increase on the 1000uf thats standard. Lastly, the bridges were MUR160 diodes I believe. So there's more to it than just using R-core transformers.
Increasing the voltage by changing R20/21 to 12k: Could detect no effect on sound.
Adding a low value cap across R5: This produced a subtle change for me. It just seemed to smooth things a little without losing any detail. It is subtle, but enough to make me put it back after I disconnected to verify! I used 47pf silver mica which was the lowest value cap I could find in the parts stash.
The Emerald is sounding very nice, and I'm really enjoying it. My intention when I contacted Richard was to get the kit was to try it out as standard, but then also try it with a different power supply and I'll get to that soon.
Thanks to Richard for the kit, the superb packing and instructions, and help and the rest of the builders here for their obs to help us all.
Fran
R-core 15v transformers: I really think I got a boost n bass response when I swapped over to these transformers. Now there are a few things to bear in mind. First off, the R-cores are Selectronic from France, secondly the secondary voltage is 15v, so I had to go to 35v caps for the input, and the only ones I had were 1500uf, so this is a little increase on the 1000uf thats standard. Lastly, the bridges were MUR160 diodes I believe. So there's more to it than just using R-core transformers.
Increasing the voltage by changing R20/21 to 12k: Could detect no effect on sound.
Adding a low value cap across R5: This produced a subtle change for me. It just seemed to smooth things a little without losing any detail. It is subtle, but enough to make me put it back after I disconnected to verify! I used 47pf silver mica which was the lowest value cap I could find in the parts stash.
The Emerald is sounding very nice, and I'm really enjoying it. My intention when I contacted Richard was to get the kit was to try it out as standard, but then also try it with a different power supply and I'll get to that soon.
Thanks to Richard for the kit, the superb packing and instructions, and help and the rest of the builders here for their obs to help us all.
Fran