Pultec EQ for instrument
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Mendelt
Well-known member
I like it but...
A lot of people use pulltecs for the extra flavor the tube gain stage gets you.. A couple of opamps won't sound the same.
If you're going to spend money on capacitors and inductors for an EQ like this you might as wel use some better opamps ( NE5532??? ). I don't know what's available where you live.
I'd use two batteries to get symetrical power for the opamps. This way you won't need to bias them to 4.5V and you can lose a lot of interstage coupling capacitors.
A lot of people use pulltecs for the extra flavor the tube gain stage gets you.. A couple of opamps won't sound the same.
If you're going to spend money on capacitors and inductors for an EQ like this you might as wel use some better opamps ( NE5532??? ). I don't know what's available where you live.
I'd use two batteries to get symetrical power for the opamps. This way you won't need to bias them to 4.5V and you can lose a lot of interstage coupling capacitors.
..and you need something bigger than the 10u coupling cap at the input of the filter stage..
chrissugar
Well-known member
I did some measurement last year for input impedance of the pultec type filter and at some extreme settings the impedance goes down to aprox 1.5 kohms. Thet is a very heavy load for a TL07x series opamp (and also for other opamps). I would use a transformer or even better go direct into the filter circuit like in the deParavicini version of Pultec. I read in an interview with mister deParavicini that the input of his Pultec has no transformer or active circuit (the input of the eq is the filter circuit).
That is how I use my mastering version of pultec and it works like a dream.
chrissugar
That is how I use my mastering version of pultec and it works like a dream.
chrissugar
Thanks friends for the answers.
Actually I like to have preamp with EQ for instrument (in my case bass guitar). Many bass players use this pultec for live or recording.
In one old topic, Jakob tell me that the one possibility is to use g9 and pultec version in his site. This is not too hard to make it, but more easy will be some discrette version or some hybrid version, and this above is compromise version
Actually I like to have preamp with EQ for instrument (in my case bass guitar). Many bass players use this pultec for live or recording.
In one old topic, Jakob tell me that the one possibility is to use g9 and pultec version in his site. This is not too hard to make it, but more easy will be some discrette version or some hybrid version, and this above is compromise version
I would think the JML DI card could drive the low imp pultec network.
If you change the on board resistor to give it 20 db of gain, you could go straith out of the pultec network without makeup amp and into a high imp bass amp or any high imp input.
If you change the on board resistor to give it 20 db of gain, you could go straith out of the pultec network without makeup amp and into a high imp bass amp or any high imp input.
clintrubber
Well-known member
[quote author="chrissugar"]IdeParavicini version of Pultec.[/quote]
Hadn't heard of that before and couldn't really find direct info. How is his version different from the original Pultec ?
Thanks,
Peter
edit: ah, found some: http://www.ear-yoshino.com/productdetails.asp?page=3&id=28
Hadn't heard of that before and couldn't really find direct info. How is his version different from the original Pultec ?
Thanks,
Peter
edit: ah, found some: http://www.ear-yoshino.com/productdetails.asp?page=3&id=28
[quote author="Joechris"]I would think the JML DI card could drive the low imp pultec network.
If you change the on board resistor to give it 20 db of gain, you could go straith out of the pultec network without makeup amp and into a high imp bass amp or any high imp input.[/quote]
The JLM hybrid opamp can drive the low impedance network as well. They are inexpensive and good for this type of thing.
http://jlmaudio.com/JLM%20Hybrid%20opamp.htm
Chris
If you change the on board resistor to give it 20 db of gain, you could go straith out of the pultec network without makeup amp and into a high imp bass amp or any high imp input.[/quote]
The JLM hybrid opamp can drive the low impedance network as well. They are inexpensive and good for this type of thing.
http://jlmaudio.com/JLM%20Hybrid%20opamp.htm
Chris
chrissugar
Well-known member
[quote author="crm0922"]
The JLM hybrid opamp can drive the low impedance network as well. They are inexpensive and good for this type of thing.
http://jlmaudio.com/JLM%20Hybrid%20opamp.htm
[/quote]
This is exactly how they do it in the famous Moonleey eq. They use a similar low impedance driver (IC plus pair of transistors) before the filter section.
The advantage is that this circuit can also act as a balanced input receiver. Two problems solved with one simple solution. :thumb:
chrissugar
The JLM hybrid opamp can drive the low impedance network as well. They are inexpensive and good for this type of thing.
http://jlmaudio.com/JLM%20Hybrid%20opamp.htm
[/quote]
This is exactly how they do it in the famous Moonleey eq. They use a similar low impedance driver (IC plus pair of transistors) before the filter section.
The advantage is that this circuit can also act as a balanced input receiver. Two problems solved with one simple solution. :thumb:
chrissugar
clintrubber
Well-known member
FWIW, w.r.t. driving the Pultec-EQ we also had this thread:
http://www.groupdiy.com/index.php?topic=11520&postdays=0&postorder=asc&start=0
Some more on the Moonlie-driver and an alternative with more parts but less questions.
Regards,
Peter
http://www.groupdiy.com/index.php?topic=11520&postdays=0&postorder=asc&start=0
Some more on the Moonlie-driver and an alternative with more parts but less questions.
Regards,
Peter
matthias
Well-known member
I'm currently planning my new pultec type eq...
I wanted to use a ll1540 for the line input...
@chris: would you prefer the jlm driver or an input transformer ??
I wanted to use a ll1540 for the line input...
@chris: would you prefer the jlm driver or an input transformer ??
[quote author="matthias"]I'm currently planning my new pultec type eq...
I wanted to use a ll1540 for the line input...
@chris: would you prefer the jlm driver or an input transformer ??[/quote]
LL1540 is a high-impedance line input device - NOT really optimal for interfacing to low-z stuff like the pultec filter. This is why I recommend using the 5402 (which is really an output transformer) in the pultec project.
Jakob E.
I wanted to use a ll1540 for the line input...
@chris: would you prefer the jlm driver or an input transformer ??[/quote]
LL1540 is a high-impedance line input device - NOT really optimal for interfacing to low-z stuff like the pultec filter. This is why I recommend using the 5402 (which is really an output transformer) in the pultec project.
Jakob E.
I'm building an EQP-1 filter section with the MEQ-5 mid cut. Waiting on the MEQ-5 inductor from Sowter! I'm trying a Baby Animal with a 990 for makeup gain (but I'm wondering if I'll have to switch to the hybrid). Also using an Edcor 600/600 on the input.
jensenmann
Well-known member
[quote author="Joechris"]If you change the on board resistor to give it 20 db of gain, you could go straith out of the pultec network without makeup amp and into a high imp bass amp or any high imp input.[/quote]
Isn´t there danger to run the inductors into saturation with this high input level?
Isn´t there danger to run the inductors into saturation with this high input level?
