Friends. About 2 years ago, I have armed the preamplifier published by TNT, called "Solidphono".
It is supposed to be an imitation of the Lehmann Black Cube.
I have exactly armed with components suggested in this page, by substituting SSM2017 by SSM2019.
Res has respected the passive RIAA him with the values specified there.
The only thing that can influence negatively is that the power supply PCB and preamplifier are made by me based on a publication by a Russian website (which I have found anymore)
The power supply has Schottky rectifier diodes and transformer is a + - 20 ac / 1a.
Yesterday I had some free time and I've done wiring and putting into operation.
Honestly I was surprised performance.
Soundstage is wide; music extends far back and forward; shows details that were not perceived; an impressive dynamism; powerful bass but not dirty details.
This description do RQ compared to RQ 970BX Rotel preamp; Cambridge Azur 551P and a modest DIY posted on Internet Rod Elliot OPA2134 IC.
The first two and the third course exelentes good enough for the cost of assembly.
The question: someone has made, has heard ?.
I need your opinions, and sound quality that each "little teacher with his little book" and when you build something, it seems that is what I
thank you very much.
It is supposed to be an imitation of the Lehmann Black Cube.
I have exactly armed with components suggested in this page, by substituting SSM2017 by SSM2019.
Res has respected the passive RIAA him with the values specified there.
The only thing that can influence negatively is that the power supply PCB and preamplifier are made by me based on a publication by a Russian website (which I have found anymore)
The power supply has Schottky rectifier diodes and transformer is a + - 20 ac / 1a.
Yesterday I had some free time and I've done wiring and putting into operation.
Honestly I was surprised performance.
Soundstage is wide; music extends far back and forward; shows details that were not perceived; an impressive dynamism; powerful bass but not dirty details.
This description do RQ compared to RQ 970BX Rotel preamp; Cambridge Azur 551P and a modest DIY posted on Internet Rod Elliot OPA2134 IC.
The first two and the third course exelentes good enough for the cost of assembly.
The question: someone has made, has heard ?.
I need your opinions, and sound quality that each "little teacher with his little book" and when you build something, it seems that is what I
thank you very much.
Thank you very much for responding. It is true, according to the espacificaciones, the SSM2019 has very low noise. Someone commented that the Lehmann Black Cube using such IC.
As for the changes that you suggest to the RIAA network they are correct if you use the "Calculate passive RIAA EQ Network".
The problem is that you should buy resistors with greater precision than I can access (I used 1% metal film).
Greetings and I keep waiting for someone who has built this circuit.
As for the changes that you suggest to the RIAA network they are correct if you use the "Calculate passive RIAA EQ Network".
The problem is that you should buy resistors with greater precision than I can access (I used 1% metal film).
Greetings and I keep waiting for someone who has built this circuit.
Might want to investigate using the SSM2019 in balanced input mode, very easy in this application and the high cmrr will make hum pick up a non issue. May need to rewire arm and leads. Surprised SY made no mention of this tidbit. Ideally you'd want a 23.7K resistor from each input to ground. Remove the 47K..
A small resistor at the each input (say 100 ohms) is good practice both from an EMC immunity standpoint and for a little ESD protection, the penalty is a bit more noise, otoh the internal cartridge resistance if MM is going to be much higher and will be the dominant noise resistance...
A small resistor at the each input (say 100 ohms) is good practice both from an EMC immunity standpoint and for a little ESD protection, the penalty is a bit more noise, otoh the internal cartridge resistance if MM is going to be much higher and will be the dominant noise resistance...
Thanks Kevinkr. I searched on the internet about making balanced input.
I encountered the problem that the magnetic capsules are attached to an output ground - signal.
On the other hand it would have to change the wiring inside the turntable arm.
It would be very interesting to do this, but I fear of damaging the capsule and arm. Greetings and thanks.
I encountered the problem that the magnetic capsules are attached to an output ground - signal.
On the other hand it would have to change the wiring inside the turntable arm.
It would be very interesting to do this, but I fear of damaging the capsule and arm. Greetings and thanks.
I find that the SBYV28-150 generates less HF noise than the SBYV27. Both are good but the 28-150 is better -- at least in my testing. I also suggest that you split the filter cap upstream of the 15V regulator, just as you have split the filter cap downstream. Divide C6 into two pieces, each piece 2200 uF, and put a 50R series resistor between the two halves. Get some line rejection rolloff before the regulator.
D11 and D12 might be drawn upside down, if you are attempting to copy the protection diodes from the LM317 style voltage regulator. In the LM317 circuit, the purpose of D11 and D12 is to protect the pass transistor when the output suddenly becomes shorted to ground. Then D11 and D12 discharge C13 and C14 -- if you turn them the other way.
D11 and D12 might be drawn upside down, if you are attempting to copy the protection diodes from the LM317 style voltage regulator. In the LM317 circuit, the purpose of D11 and D12 is to protect the pass transistor when the output suddenly becomes shorted to ground. Then D11 and D12 discharge C13 and C14 -- if you turn them the other way.
If you put those diodes in parallel with the B-E of the emitter followers, you decrease their current gain enough that the 10k base feed would leave very little current to run the Zener.
Do you really need these protection diodes given that there are large resistors in series with the outputs of the EFs anyway?
Or maybe just actually use LM317/337...
Do you really need these protection diodes given that there are large resistors in series with the outputs of the EFs anyway?
Or maybe just actually use LM317/337...
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I believe D11 and D12 are reverse biased as shown, but they are not really necessary with this circuit.. I would add a simple error amplifier using a single transistor and bootstrap the zener off of the output side.
FWIW most modern magnetic cartridges are already balanced.. Some do have a shield connected to one of the "gnd" terminals but this is usually easy to defeat. (Many Shure cartridges had a tag that could be snipped at one point in time. - I had several)
FWIW most modern magnetic cartridges are already balanced.. Some do have a shield connected to one of the "gnd" terminals but this is usually easy to defeat. (Many Shure cartridges had a tag that could be snipped at one point in time. - I had several)
Well, since I've written three articles on this...
Generally, the tonearm doesn't have to be rewired, but the leads from the turntable to the preamp have to be changed. This is fortunate because the former is really difficult and the latter is really easy. Balanced is a far better way to run that chip anyway because of the high input bias currents versus the low input offset current.
IIRC, you tried that chip (or the equivalent THAT chip) in phono service and weren't impressed. Am I remembering correctly?
I'd suggest using inductors (rather than 75ohm resistors) on the supply lines. With the resistor the output impedance at LF is dominated by the capacitor - that's going above 1ohm at LF. Find some inductors with low DCR (I use 220uH bobbin wound chokes, they have about 0.2 DCR). Also rather than a single 4700uF cap, use paralleled lower values if possible. The ESR and ESL get better then - meaning lower rail noise at HF. So then the paralleled film cap may well become redundant.
I'd also suggest going as high as noise will allow for the feedback network around the OP275 - again the aim is to reduce power supply noise. Opamps have classAB output stages and to get the best subjectively I always aim to keep them running in classA.
Sorry if I wasn't clear. As shown D11 and D12 are reverse biased, I was referring to Mark Johnson's suggestion to turn them around.
I agree about the error amplifier. But then why not something like LM317. What is the perceived advantage of using relatively low loop gain gain EF + discrete error amp and passive filters in the power supply rather than voltage regulators with lots of feedback? Especially if LF impedance and ripple rejection are concerns. I guess it's not obvious how the noise compares, but in any case the ICs used in the amplifier probably still have decent PSRR at 20 kHz ...
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Hello. Sorry but I'm not good with English.
So I suggest, D11 and D12 would redound and tended to withdraw them.
The change of 75 ohms per inductor can do.
I get confused when I say I use an error amplifier.
The circuit poses TNT offers another power supply, but is more complex to perform my (PCB harder)
So I suggest, D11 and D12 would redound and tended to withdraw them.
The change of 75 ohms per inductor can do.
I get confused when I say I use an error amplifier.
The circuit poses TNT offers another power supply, but is more complex to perform my (PCB harder)
The DIYAUDIO Store has the Jung/Didden power supply boards in stock -- this is an excellent power supply. Super Regulator V2.2 - Power Supplies and Accessories - Circuit Boards
Hello again.
I am now to discuss changes I've made.
First I have focused on improving the passive RIAA network as I had suggested Jackinnj.
I have confirmed with passive RIAA calculator Kabusa and values are those that I mentioned Jackinnj.
I have taken the trouble to remove all network components RIAA preamps for measuring both their resistors and capacitors.
(I sent instrumenteo link the measurement you ordered in Alliexpress has precision of up to tens of ohms and measured from 30 pF to 100000microfaradios also measured diodes;.. Transistors, inductors.
Wholesale Product Snapshot Product name is Digital ESR Meter Mega328 Transistor Tester Diode Triode Capacitance MOS/PNP/NPN L/C/R TESTER METER).
The resistors were right. They are metal film 1% tolerance.
But capacitors, although they were ordered on Ebay and are WIMA have significant error.
The 0.33 uF has one 0.302 and the other 0.311 uF.
The 0.1 with 0.090 uF each.
I have brought with capacitors in parallel to 0.32 and 0.108 equalized for both channels.
Oddly enough the change was amazing. The dynamism was already present; but the three-dimensional image and tone of the instruments and voices is really amazing.
No doubt the best I have heard. (Clear told that "I" have heard).
They add other data. As I have to wear a cartridge Audio Technica AT 440 MLa and needs 47 k load and 100 pF capacitance, I removed the capacitor charging as the multimeter commenting them could measure the capacitance cables turntable and I was cutting until its length corresponds to 95 pF.
I think he has been to me a fairly tight system and a sound that had never been achieved.
Lack improvements in the power supply as I have suggested here.
Of course it keeps.
I go for the JFET Boozhound.
Greetings and I hope someone will be encouraged to join this phono stage so know your opinion.
I am now to discuss changes I've made.
First I have focused on improving the passive RIAA network as I had suggested Jackinnj.
I have confirmed with passive RIAA calculator Kabusa and values are those that I mentioned Jackinnj.
I have taken the trouble to remove all network components RIAA preamps for measuring both their resistors and capacitors.
(I sent instrumenteo link the measurement you ordered in Alliexpress has precision of up to tens of ohms and measured from 30 pF to 100000microfaradios also measured diodes;.. Transistors, inductors.
Wholesale Product Snapshot Product name is Digital ESR Meter Mega328 Transistor Tester Diode Triode Capacitance MOS/PNP/NPN L/C/R TESTER METER).
The resistors were right. They are metal film 1% tolerance.
But capacitors, although they were ordered on Ebay and are WIMA have significant error.
The 0.33 uF has one 0.302 and the other 0.311 uF.
The 0.1 with 0.090 uF each.
I have brought with capacitors in parallel to 0.32 and 0.108 equalized for both channels.
Oddly enough the change was amazing. The dynamism was already present; but the three-dimensional image and tone of the instruments and voices is really amazing.
No doubt the best I have heard. (Clear told that "I" have heard).
They add other data. As I have to wear a cartridge Audio Technica AT 440 MLa and needs 47 k load and 100 pF capacitance, I removed the capacitor charging as the multimeter commenting them could measure the capacitance cables turntable and I was cutting until its length corresponds to 95 pF.
I think he has been to me a fairly tight system and a sound that had never been achieved.
Lack improvements in the power supply as I have suggested here.
Of course it keeps.
I go for the JFET Boozhound.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Greetings and I hope someone will be encouraged to join this phono stage so know your opinion.
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