Thanks, that's really helpful.
So with the 1st jumper closed the value would be the sum of R1 and R2 on the emerald plus the switchboard selected resistance in parallel.
e.g. 1/(1/R1 (emerald) + 1/R2 (emerald) + 1/R1(switchboard)) assuming R1 only on the swtchboard is on.
I mainly use MM carts with a preference for 100k or 47k, but also have a few MC carts as well. Hence my reason for asking.
So with the 1st jumper closed the value would be the sum of R1 and R2 on the emerald plus the switchboard selected resistance in parallel.
e.g. 1/(1/R1 (emerald) + 1/R2 (emerald) + 1/R1(switchboard)) assuming R1 only on the swtchboard is on.
I mainly use MM carts with a preference for 100k or 47k, but also have a few MC carts as well. Hence my reason for asking.
Yes, as you say with the jumper closed it's the sum of three resistors in parallel.
Normally you wouldn't close the jumper when using the switchboard, but if you are comfortable with the calculations, then doing so does allow some additional fine tuning... though many of the combinations are unlikely to be useful.
Normally you wouldn't close the jumper when using the switchboard, but if you are comfortable with the calculations, then doing so does allow some additional fine tuning... though many of the combinations are unlikely to be useful.
I ended up building a balanced Emerald over the last couple of weeks. Since the rest the signal chain in my setup is balanced I figured it couldn't hurt to see if there was any benefit. The balanced build was stock except for C3 being a Mundorf Mcap and I had a transformer and rectifier for each channel. I made a 5-pin DIN to XLR cable for the balanced Emerald using Mogami w2534. For my everyday Emerald I have C3 being Sonicaps and the opamps are OPA627 and LME47910. I use a Zavfino Majestic DIN-RCA for my everyday listening.
I was unable to find much of a difference between the 2 Emeralds. The soundstage of the balanced version might have been a bit better defined, but I'd be hard pressed to tell during a DBX test. I'll probably put some more hours on the balanced just to see if things change at all but for now I'd have to say that the 2nd set of boards, 2nd power supply, and mess of wiring isn't worth the cost and complexity. If something changes over the next 100 hours on the balanced version I'll let you all know.
I was unable to find much of a difference between the 2 Emeralds. The soundstage of the balanced version might have been a bit better defined, but I'd be hard pressed to tell during a DBX test. I'll probably put some more hours on the balanced just to see if things change at all but for now I'd have to say that the 2nd set of boards, 2nd power supply, and mess of wiring isn't worth the cost and complexity. If something changes over the next 100 hours on the balanced version I'll let you all know.
Finally got it all assembled and connected. Haven’t got a proper case yet. Cut up an old cd player top plate and put it all in place.
Hooked it up to my Lenco L75 and Yamaha amp and it made music. I didn’t do any extensive listening but with my ear to the speaker there was a slight hum which was audible away when increasing the volume. This noise hasn’t been present before when using the Yamaha phono input or my old MF V-LPS. I’ll do some more listening and testing to try and source it.
Still I’m happy it was working right away, first real hifi diy build
Hooked it up to my Lenco L75 and Yamaha amp and it made music. I didn’t do any extensive listening but with my ear to the speaker there was a slight hum which was audible away when increasing the volume. This noise hasn’t been present before when using the Yamaha phono input or my old MF V-LPS. I’ll do some more listening and testing to try and source it.
Still I’m happy it was working right away, first real hifi diy build
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Hi, Everybody ...
I like to ask somebody for some help ...
I build my own Emerald Phono preamp, the "Slowdiyer" PCB version ... But I have a problem with hum / buzz from power supply, I have center tapped 24V transformers and I made PSU with one bridge rectifier, I´ll try use 2 transformers for two separately 12V wirings with 2 bridge rectifier and all the same, my last try was increase 1000uF capacitors to 3900uF, and still, hum is present ...
I have LM317/337/LF353 board and I connect him between transformer and Emerald modules and now, preamp is deadly silent ...
Does anyone have any idea how to get rid of the hum with the original power supply wirings?
I like to ask somebody for some help ...
I build my own Emerald Phono preamp, the "Slowdiyer" PCB version ... But I have a problem with hum / buzz from power supply, I have center tapped 24V transformers and I made PSU with one bridge rectifier, I´ll try use 2 transformers for two separately 12V wirings with 2 bridge rectifier and all the same, my last try was increase 1000uF capacitors to 3900uF, and still, hum is present ...
I have LM317/337/LF353 board and I connect him between transformer and Emerald modules and now, preamp is deadly silent ...
Does anyone have any idea how to get rid of the hum with the original power supply wirings?
I probably did know about this fork at some point, but I forgot and had to Google it.
So this one.
Anyway, while counter-intuitive, using the Emerald with external regulators like LM317 can lead to a lot of hum and general oddities. So too can external filter capacitors. What you need to do is connect the bridge rectifier directly to the Emerald boards, with nothing in between the two but wire.
So this one.
Anyway, while counter-intuitive, using the Emerald with external regulators like LM317 can lead to a lot of hum and general oddities. So too can external filter capacitors. What you need to do is connect the bridge rectifier directly to the Emerald boards, with nothing in between the two but wire.
I am very interested in this, since i have a similar problem.
My Emeralds not only hum, but they also have a lot of noise a bit higher up in frequency.
I sinned by putting a 470uF cap after each bridge rectifier output in the power supply, but before removing that i am waiting for new op amps since i can't remember where i got the old ones from.
I hope there are no objections to using OPA227 instead of OPA27?
Thank you for your help, werner
My Emeralds not only hum, but they also have a lot of noise a bit higher up in frequency.
I sinned by putting a 470uF cap after each bridge rectifier output in the power supply, but before removing that i am waiting for new op amps since i can't remember where i got the old ones from.
I hope there are no objections to using OPA227 instead of OPA27?
Thank you for your help, werner
OPA2227 is a drop in replacement for the OP-27/OPA27, I don't expect any issues.
With respect to noisy power supplies, filtering isn't the answer but it isn't necessarily the problem either. The Emerald circuit has enough voltage regulation to remove all the power supply noise from the voltages powering the op amps, but if the V++ and V-- has a lot of ripple this noise can couple to the input by other means, such as a ground loop. Using preregulated V++ and V-- will "solve" the noise problem, because even with the ground loop there is no ripple on the V++ and V-- anymore to couple into the signal, but it doesn't remove the mistake in the layout which allowed the coupling to occur in the first place, a mistake which can cause the performance to degrade in other ways.
(aside: this partly explains the popularity of battery power in diy audio - no matter how terrible your layout is, you'll never have hum/ripple issues because there is no such noise present to start with)
Even with no external regulation or filtering, the output of Emerald should be silent, with no hum of excess noise above the baseline hiss from the op amps. Getting to that point, however, requires good cable dress, proper layout and grounding, and appropriate shielding in e.g. the phono cables.
Hi everyone, I've gone ahead and ordered the Emerald boards from Richard which I'm itching to get built up!
My plan is to use a stepped attenuator to allow the phono stage to run direct into my active speakers, which have a 13kOhm input impedance. I'm trying to get my head around how critical the attenuator impedance is. I've been offered a 50k Goldpoint attenuator, would that be ok with the Emerald?
Thanks in advance.
My plan is to use a stepped attenuator to allow the phono stage to run direct into my active speakers, which have a 13kOhm input impedance. I'm trying to get my head around how critical the attenuator impedance is. I've been offered a 50k Goldpoint attenuator, would that be ok with the Emerald?
Thanks in advance.
I´m back about report with hum problem ...
Iĺl try change ground wirings, but without any progress and only option for "deadly silent" is using Emerald boards with regulated power supply with LM317/337 ...
I like to ask, when I use this connection, what voltage values I must set on the output ? Can I work with lower voltage than +/-18V ?
Iĺl try change ground wirings, but without any progress and only option for "deadly silent" is using Emerald boards with regulated power supply with LM317/337 ...
I like to ask, when I use this connection, what voltage values I must set on the output ? Can I work with lower voltage than +/-18V ?