Ricardo,
Please note in bolt:
Yes these are mine real values, unfortunately I trusted in Pcx because I have ordered & paid matched pairs
.
So it's not necessary 68pF to reach the 16nF for C3, I will remove in both channels?
Tomorrow I will let you know exact values of R1.
Not I haven't got more resistors I have to order more, please be sure with values as you know this kind of resistors are expensives, thks.
Please note in bolt:
Are these the real values on your build ? I wish you had made pairs before soldering.
I also need to know the real 3k3 value.
Admiting 3k3 = 3k3 sharp, in the Left channel you can // 1M5R5-1M13 to 47k and 300p // 47n......you will be very close to heaven.
Now the other channel is bad.... the main problem is 6k9 R4-6K79that should go down to 6k77 .... You will gain lots of presence that way in this channel. Also I would go for 1M7 // 46k8 and 300p // 47n.
All this with 15.6n // 330p as initially.
Now it would really be good to have both channels with the same values... do you have more resistors so you can make equivalent pairs ?
Regards
Ricardo
Yes these are mine real values, unfortunately I trusted in Pcx because I have ordered & paid matched pairs
.So it's not necessary 68pF to reach the 16nF for C3, I will remove in both channels?
Tomorrow I will let you know exact values of R1.
Not I haven't got more resistors I have to order more, please be sure with values as you know this kind of resistors are expensives, thks.
From data-sheet Erno Borbely Web:
Circuit description.
The schematic of the EB-199/320 is shown in fig. 2. The first amplifier is a linear one, using 4 pairs of low-noise Cascoded JFETs at the input. The second stage is also made up of low-noise Cascoded JFETs. The output stage is a complementary MOSFET source follower. The gain can be changed with the feedback resistors to 20, 30, 40 and 49dB. R28-C15 provides the high frequency roll-off of the RIAA equalization.
The second amp provides the bass boost of the RIAA curve. Except for the input stage, which is a complementary differential Cascode circuit, the amplifier has the same topology as the input stage. The second amp has a gain of 24 dB at 1 kHz, making a total gain of 54 and 64-73 dB for the phono preamp.
Due to the high gain at low frequencies (64-93dB!), both stages are using servo control for DC-offset. The offset control is provided by low-noise JFET-input opamps. The opamps are supplied with ±10V from shunt regulators
Typical Specifications.
Gain: 1st stage: 20, 30, 40 or 49dB (20dB for MM)
2nd stage : 24dB
THD 3VRMS/1kHz: 0.002%
Max. Output voltage: approx. 9VRMS
Risetime (without RIAA network): 0.3/0.4usec
RIAA Accuracy: better than 0.2dB
Equivalent input noise: <100nV, 20Hz-30kHz
Secret questions ask directly to Erno, but for sure don't tell you
, I'm sure that the real Merlin The Wizard is Erno & his magic.
Of course. And when Merlin starts designing and becomes famous then we will have the first with 3 letter acronym or more.
MEM or MTW?
Ricardo,
Please note in bolt:
Yes these are mine real values, unfortunately I trusted in Pcx because I have ordered & paid matched pairs
So it's not necessary 68pF to reach the 16nF for C3, I will remove in both channels?
Tomorrow I will let you know exact values of R1.
Not I haven't got more resistors I have to order more, please be sure with values as you know this kind of resistors are expensives, thks.
I am sorry I can not understand what the bold values mean.
If you want I can calculate the "best" values for each channel but I need the 3k3 values.
You can leave the 68p for now because my calc indicate aprox 16.0n for each channel as is
Look at the simulator results based on your previous indications.
The green cells indicate the best value, above are aproximations I gave you before.
I would choose the higher valued ones... Let me know your final choice.
I am sorry I can not understand what the bold values mean.
If you want I can calculate the "best" values for each channel but I need the 3k3 values.
You can leave the 68p for now because my calc indicate aprox 16.0n for each channel as is
Look at the simulator results based on your previous indications.
The green cells indicate the best value, above are aproximations I gave you before.
The bold values are mine right values.
Tomorrow I measure mine special R1 trimmers & let you know the exact value.
Ok I leave the 68pF in both channels.
I can't understand the simulator values, only understands green best values but see only Left channel in both simulations?
Sorry, the right table should read Merlin Right.
I see that your made new measurements so I must restart again.
Please send me the following values Left and Right:
R1 3k3
R3 47k
R4 6k8
R5 1M
I will use your previous info:
C2 46.3n both channels
C3 16n both channels
My guess is that he is over compensating with R1 trimmer for bias voltages and mismatch for the burned duet. Which is normal for when he was seeking bias to make it initially just work. If he can set them for 3.3k sharp, and the bias voltages will be still in acceptable bracket, then you will have a reference point. I also run a Lipshitz inverse feeder in his circuit. The main arbitrary points are R1 and C3. With his now bold typeface deviations, it seems that a basic C3 without the extras, can lift it a bit, because it looks indeed dropping enough, especially if he had overshoot 3k3.
Ok
With the new value of R4 right, the picture looks much better now:
My suggestions are:
Left channel place a 1M4 over R3 and a 470p over C2
Right channel place a 1M9 over R3 and a 450p over C2
LEFT
R1 3k3
R3 47k // 1M4
R4 6k8
R5 1M13
C3 15n6 + 330p + 68p
C2 46.3n // 470p
RIGHT
R1 3k3
R3 46k8 // 1M9
R4 6k79
R5 998k
C3 15n6 + 330p + 68p
C2 46.4 // 450p
With the new value of R4 right, the picture looks much better now:
My suggestions are:
Left channel place a 1M4 over R3 and a 470p over C2
Right channel place a 1M9 over R3 and a 450p over C2
LEFT
R1 3k3
R3 47k // 1M4
R4 6k8
R5 1M13
C3 15n6 + 330p + 68p
C2 46.3n // 470p
RIGHT
R1 3k3
R3 46k8 // 1M9
R4 6k79
R5 998k
C3 15n6 + 330p + 68p
C2 46.4 // 450p
Off course, just lifting the 330p and 68p from C3, will lift everything producing imediate high definition but IMO, bypassing R3 with the big resistors will add so much more presence in bass and highs that C3 should be kept as is 16n.
After the big resistors, bass can become overwelming so I would increase C2 by 470p to bring back Low mids and snap.
After the big resistors, bass can become overwelming so I would increase C2 by 470p to bring back Low mids and snap.