Hi all, I'm posting this in hope that any of our members is familiar with the Harman Kardon Citation 11 preamp circuits, and can give me some advice.
I'm a novice with experience building kits from Dynaco in the 70's and lately from updatemydynaco.com to upgrade my Dynaco gear. So that's the extent of my abilities, I can follow instructions! My knowledge level in circuit diagrams and electrical theory and troubleshooting electrical circuitry is very limited. At the moment, I'm trying to solve a problem with the EQ section of my HK Cit 11.
The 60hz slider works on one channel & not the other. The other sliders (320, 1K, 5K & 12K) work fine on both channels. The Cit 11 has individual EQ boards for each channel, making it easy to spot any problems between one board & the other.
The parts list calls for a 1H 10% choke. No other specs are listed.
I checked resistance across the inductors on each board for each of the sliders and the value for the choke tied to the 60hz sliders measured .452K ohms on one and 14.02M ohms on the other.
I'm not sure which is the correct value, but judging from the values I measured across the other sliders, maybe it's the board that measured only 14.02m ohms. For example the 320hz sliders measure 321.5 ohms on one board, and 318 ohms on the other, the 1Khz sliders measured 97.1 ohms on one 96.4 ohms on the other. That's my thinking...
I pulled off the covers that shield the choke assemblies and looked at the chokes and they seemed fine, I unsoldered the choke that was reading 14.02m ohms and measured across its leads, and now get 0 reading. making me think that the heat from the iron finally made it fail.
I've searched online for 1H chokes, and come up with nothing even close to what HK installed. I attach pictures for reference. I'm not sure if any other specs can be gleaned from the circuit diagram that I need to be looking for, but typing in "1H" and 1000mH" inductors on the various parts websites doesn't return anything I feel I can order confidently as a substitute for the original.
Visually, the choke is about 3/4" long, about 3/8" in diameter and covered in a waxy plastic. An interesting note is the space occupied by the 1H choke is labelled 1.4H on the board diagram! But it seems the boards in the 11 have many such mis-labelings so I'm not too concerned. Maybe I should be?
I'm wondering if any members who are more technically knowledgeable than I could steer me to a modern day equivalent.
Thanks in advance for any assistance!
I'm a novice with experience building kits from Dynaco in the 70's and lately from updatemydynaco.com to upgrade my Dynaco gear. So that's the extent of my abilities, I can follow instructions! My knowledge level in circuit diagrams and electrical theory and troubleshooting electrical circuitry is very limited. At the moment, I'm trying to solve a problem with the EQ section of my HK Cit 11.
The 60hz slider works on one channel & not the other. The other sliders (320, 1K, 5K & 12K) work fine on both channels. The Cit 11 has individual EQ boards for each channel, making it easy to spot any problems between one board & the other.
The parts list calls for a 1H 10% choke. No other specs are listed.
I checked resistance across the inductors on each board for each of the sliders and the value for the choke tied to the 60hz sliders measured .452K ohms on one and 14.02M ohms on the other.
I'm not sure which is the correct value, but judging from the values I measured across the other sliders, maybe it's the board that measured only 14.02m ohms. For example the 320hz sliders measure 321.5 ohms on one board, and 318 ohms on the other, the 1Khz sliders measured 97.1 ohms on one 96.4 ohms on the other. That's my thinking...
I pulled off the covers that shield the choke assemblies and looked at the chokes and they seemed fine, I unsoldered the choke that was reading 14.02m ohms and measured across its leads, and now get 0 reading. making me think that the heat from the iron finally made it fail.
I've searched online for 1H chokes, and come up with nothing even close to what HK installed. I attach pictures for reference. I'm not sure if any other specs can be gleaned from the circuit diagram that I need to be looking for, but typing in "1H" and 1000mH" inductors on the various parts websites doesn't return anything I feel I can order confidently as a substitute for the original.
Visually, the choke is about 3/4" long, about 3/8" in diameter and covered in a waxy plastic. An interesting note is the space occupied by the 1H choke is labelled 1.4H on the board diagram! But it seems the boards in the 11 have many such mis-labelings so I'm not too concerned. Maybe I should be?
I'm wondering if any members who are more technically knowledgeable than I could steer me to a modern day equivalent.
Thanks in advance for any assistance!