Udip
Between you and me...you want to buid yourself a preamp...why not give yourself a try with the AD's SSM2019 which is designed perfectly for this function? And use the inexpensive OPA604 or the expensive OPA627 for servo. These two are equivalent and maybe the best opamp for servo DC because of low Bias currents specs.
Luke123
Between you and me...you want to buid yourself a preamp...why not give yourself a try with the AD's SSM2019 which is designed perfectly for this function? And use the inexpensive OPA604 or the expensive OPA627 for servo. These two are equivalent and maybe the best opamp for servo DC because of low Bias currents specs.
Luke123
peranders,
First of all...thanx for the answers....
Regarding the simulation files, as I said, I can't tell the
format they are written in...what software should i use?
Luke123,
The preamp should be a high-end, and will be used
for music recording...so I guess the SSM2019 can't rival the
opa627....
I think I'll use the opa604 as the dc servo....
thanx....
First of all...thanx for the answers....
Regarding the simulation files, as I said, I can't tell the
format they are written in...what software should i use?
Luke123,
The preamp should be a high-end, and will be used
for music recording...so I guess the SSM2019 can't rival the
opa627....
I think I'll use the opa604 as the dc servo....
thanx....
Udip
I also love the 627 but...
Tell me. Why can't 2019 rival with it?
You use a transformer. Good for CMRR but you use resistors on input... so down goes your CMRR. CMRR vs frequency which Transformer is great for is then useless compromised.
The 2019 all handles these features internally and much better.
Noise density is also much lower...
You can also consider the THAT 1510.
Luke123
I also love the 627 but...
Tell me. Why can't 2019 rival with it?
You use a transformer. Good for CMRR but you use resistors on input... so down goes your CMRR. CMRR vs frequency which Transformer is great for is then useless compromised.
The 2019 all handles these features internally and much better.
Noise density is also much lower...
You can also consider the THAT 1510.
Luke123
peranders,
thanx...I'll try playing around with the simulations....
Luke123,
In fact, I'm using a transformer...it's the LL1538.
I've heard that the SSM2019 is pretty good...but I don't know..
I prefer using good opamp biased in Class a, like the
opa627 or ad797......
The SSM2019 has already balanced inputs so how can
I use transformer with it?
thanx...I'll try playing around with the simulations....
Luke123,
In fact, I'm using a transformer...it's the LL1538.
I've heard that the SSM2019 is pretty good...but I don't know..
I prefer using good opamp biased in Class a, like the
opa627 or ad797......
The SSM2019 has already balanced inputs so how can
I use transformer with it?
Udip
Why insist on using a transformer on input? Dynamic mics already have one and condenser mic have cap on output. So if it's for input offsets...no need.
To have balanced inputs? 2019 is balanced.
To have excellent CMRR? You're detroying it with your resistors..unless you select them with 0.001% precision!!! Check the 2019 CMRR specs for fun. Even at 100KHz and gain of 100 it is better than any transformers.
The restricted bandwidth of transformer offsets the huge bandwidth and slew-rate qualities of 627/797.
The 2019 have great natural bandwidth that you can easily control. Its CMRR is superb. And noise figures are below 627/797 when you consider a gain of 100 and more. By the way 797 is great for noise voltage...if you have a very low impedance input (50-200 ohms).
Anyway I ever designed with the two and they are superb.
But for mic preamp I'd go with the SSM2019 or the excellent THAT 1510 that you at least have to look at.
Your gain controls is included (Rg). Everything in one chip.
But a transformer could be used on your output section with Servo DC or non if offset is below 2-3 mV.
Check this!
Luke123
Why insist on using a transformer on input? Dynamic mics already have one and condenser mic have cap on output. So if it's for input offsets...no need.
To have balanced inputs? 2019 is balanced.
To have excellent CMRR? You're detroying it with your resistors..unless you select them with 0.001% precision!!! Check the 2019 CMRR specs for fun. Even at 100KHz and gain of 100 it is better than any transformers.
The restricted bandwidth of transformer offsets the huge bandwidth and slew-rate qualities of 627/797.
The 2019 have great natural bandwidth that you can easily control. Its CMRR is superb. And noise figures are below 627/797 when you consider a gain of 100 and more. By the way 797 is great for noise voltage...if you have a very low impedance input (50-200 ohms).
Anyway I ever designed with the two and they are superb.
But for mic preamp I'd go with the SSM2019 or the excellent THAT 1510 that you at least have to look at.
Your gain controls is included (Rg). Everything in one chip.
But a transformer could be used on your output section with Servo DC or non if offset is below 2-3 mV.
Check this!
Luke123
Luke123,
I know the SSM2019 is balanced, that is why I asked how can I use both transformer and the SSM2019 at the same time..
"To have excellent CMRR? You're detroying it with your resistors"
What resistors? - This is why I use transformer...
I know that both the SSM2019 and INA217 are good for mic
preamps...but I still think that superb opamp like OPA627
or AD797, or a discrete one, will do better.
The SSM2019 CMMR may be better, and the noise may come close
to the 627 or 797, but these do not have much affect of sound quality.
A good Transformer color the sound a bit (in a good way),
and not mentioned are The speed (GBW, slew rate and settling time) of 627 which are much better..
I guess this is why very high-end mic preamps like API, John Hardy, and others are not build around the SSM2019.
I know the SSM2019 is balanced, that is why I asked how can I use both transformer and the SSM2019 at the same time..
"To have excellent CMRR? You're detroying it with your resistors"
What resistors? - This is why I use transformer...
I know that both the SSM2019 and INA217 are good for mic
preamps...but I still think that superb opamp like OPA627
or AD797, or a discrete one, will do better.
The SSM2019 CMMR may be better, and the noise may come close
to the 627 or 797, but these do not have much affect of sound quality.
A good Transformer color the sound a bit (in a good way),
and not mentioned are The speed (GBW, slew rate and settling time) of 627 which are much better..
I guess this is why very high-end mic preamps like API, John Hardy, and others are not build around the SSM2019.
Upupa Epops said:Mic preamps, coupling transformers : look at experience of using on www.mil-media.com
Quite interesting page!
are they worth the money?
Uli
Hi Y'all,
Not to hijack the thread but I'm insterested in the same thing.
A PSA Servo Filter for my preamp. I found a schematic on line,
in the public domain. I was interested in some improvements to
an Audio Research SP3A-1 that I've had for awhile and I don't
know how much difference it would make.
Let me find the information and I'll post it either here or in a
follow on reply if y'all don't mind.
It recommened the MC1566L chip. Dated I know but still.
It supposed to regulate voltage between 400VDC - 450VDC
and current perhaps to the heaters? Maybe not I don't know.
I was asking, I think on the tube/valve forum, but I don't
even know where to ask. Perhaps here as it is a solid state servo
but applied to tube voltage regulation.
If it is the incorrect place that is fine too, just let me know where?
This thread showed up so DIYThreadBOT askes that we post in going threads
rather than start new ones.
Cheers,
Sync
Not to hijack the thread but I'm insterested in the same thing.
A PSA Servo Filter for my preamp. I found a schematic on line,
in the public domain. I was interested in some improvements to
an Audio Research SP3A-1 that I've had for awhile and I don't
know how much difference it would make.
Let me find the information and I'll post it either here or in a
follow on reply if y'all don't mind.
It recommened the MC1566L chip. Dated I know but still.
It supposed to regulate voltage between 400VDC - 450VDC
and current perhaps to the heaters? Maybe not I don't know.
I was asking, I think on the tube/valve forum, but I don't
even know where to ask. Perhaps here as it is a solid state servo
but applied to tube voltage regulation.
If it is the incorrect place that is fine too, just let me know where?
This thread showed up so DIYThreadBOT askes that we post in going threads
rather than start new ones.
Cheers,
Sync
Here is a schematic with most values identified
and here is the actual patent. This if obviously
for high voltage. Not sure which values for the
protection diodes for the 24 AMP chip.
While old it was probably okay I should think.
Now how would we repurpose and modernize
1. for HV Pre amp, or Amp?
2. for lower voltage Solid State pre or amp?
Cheers,
Sync
and here is the actual patent. This if obviously
for high voltage. Not sure which values for the
protection diodes for the 24 AMP chip.
While old it was probably okay I should think.
Now how would we repurpose and modernize
1. for HV Pre amp, or Amp?
2. for lower voltage Solid State pre or amp?
Cheers,
Sync
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