inputoutput
Well-known member
Wrapped up the first stage of a Midrange Pultec today, with the Gyraf pcb designs & schematics.
The open space in the middle is for an extra amp of some sort. Thought it would be cool to have a switchable solution, where I can go from tube to not-tube. Does anybody have any thoughts on how I should do this? I have looked at some old Lawo opamps plus the tori-amp, but since I am an amateur at this, I dont wanna be too ambitious and make it to complicated. I would appreciate some advise before I start.
Like...., where would you pull the power to run an extra board? - I have got 12VAC 2A and 230VAC 0.1A from the tranny and I have got 6.3VDC and 12VDC after the rectifiers (on each board).
If I pull some DC from one of the boards, could this affect the balance between the left and right PSRR boards?
other info :
The power-toroid was put in an external box. And I had to swap the 3K3 2W resistor into a 20K to get the correct voltages on the PSU part of the SRPPboards
The bypass (w/relays) are connected direct on the output. I know that people often place the bypass between the filter and the amp, but since Im planning yet another solidstate opamp here, it made sense to have it on the output.
There are different types of caps on the eq-freqs. But my gut feeling so far, is that the freqs with Wima caps are "tighter" and more compact sounding. So I might change them all into wimas on the next round.
As you might see on the freq-numbers, there are some differences from the original. These were the ones that I got when measuring it.
The eq-inductors are from Sowter
Under the large caps, there are 560K bleeder resistors
Here is the FPD file if anyone is interested
http://www.kaada.no/DIY/DIY-MEQ5/wrongroom-meq-5.fpd
The open space in the middle is for an extra amp of some sort. Thought it would be cool to have a switchable solution, where I can go from tube to not-tube. Does anybody have any thoughts on how I should do this? I have looked at some old Lawo opamps plus the tori-amp, but since I am an amateur at this, I dont wanna be too ambitious and make it to complicated. I would appreciate some advise before I start.
Like...., where would you pull the power to run an extra board? - I have got 12VAC 2A and 230VAC 0.1A from the tranny and I have got 6.3VDC and 12VDC after the rectifiers (on each board).
If I pull some DC from one of the boards, could this affect the balance between the left and right PSRR boards?
other info :
The power-toroid was put in an external box. And I had to swap the 3K3 2W resistor into a 20K to get the correct voltages on the PSU part of the SRPPboards
The bypass (w/relays) are connected direct on the output. I know that people often place the bypass between the filter and the amp, but since Im planning yet another solidstate opamp here, it made sense to have it on the output.
There are different types of caps on the eq-freqs. But my gut feeling so far, is that the freqs with Wima caps are "tighter" and more compact sounding. So I might change them all into wimas on the next round.
As you might see on the freq-numbers, there are some differences from the original. These were the ones that I got when measuring it.
The eq-inductors are from Sowter
Under the large caps, there are 560K bleeder resistors
Here is the FPD file if anyone is interested
http://www.kaada.no/DIY/DIY-MEQ5/wrongroom-meq-5.fpd
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