The Crown IC-150A Preamplifier is one of those early 1970's devices with beaucoup of room in the chassis -- and it used an LM301 opamp -- the IC-150A has a stepped attenuator, tone, balance and a "panorama" control, abundant use of Siemens silvercaps -- here's the linestage and power supply -- while it is a thing of beauty, it must undergoe the surgeon's knife:
and
An externally hosted image should be here but it was not working when we last tested it.
and
An externally hosted image should be here but it was not working when we last tested it.
Hi jackinnj,
-Chris
Go for it! They didn't sound that good either. Between upgrading the power supply and other active stages, is there anything but the chassis worth keeping?while it is a thing of beauty, it must undergoe the surgeon's knife:
-Chris
Hi jackinnj,
Are you thinking discrete or another op amp unit?
-Chris
Are you thinking discrete or another op amp unit?
I probably would have gone with Ag or some other finish. Gold doesn't seem to hang around long on most jacks I've seen.they have all of the inputs grounded onto the chassis so i purchased some insulated Au-plated variety to fit in there.
-Chris
Hi FastEddy,
Hi Mark,
-Chris
Why? EI's sidestep many torroid problems and there isn't a height issue here.Is there room for a torrid xformer?
Hi Mark,
I've done a few as well. I think I'd stick with a solid state unit. Use an old computer hub for a tube project, complete with visible tubes hanging out the top!I've repaired more of these over the years that I would admit...but in reality the chassis is probably the only good part of it.
-Chris
anatech said:Hi jackinnj,
Are you thinking discrete or another op amp unit?
I probably would have gone with Ag or some other finish. Gold doesn't seem to hang around long on most jacks I've seen.
-Chris
I am going to use this combination of AD825 + AD826 for the line amp.
I think that the phono board is going to be OK.
The power supply will get a pair of super-regs.
An externally hosted image should be here but it was not working when we last tested it.
Hi jackinnj,
Ah ha! A composite op amp. Less expensive maybe than BUF04. This should be interesting to see how it plays out. I'm sure it will perform considerably better than the orginal.
-Chris
Ah ha! A composite op amp. Less expensive maybe than BUF04. This should be interesting to see how it plays out. I'm sure it will perform considerably better than the orginal.
Yup. Can't hurt.The power supply will get a pair of super-regs.
-Chris
anatech said:Hi jackinnj,
Ah ha! A composite op amp. Less expensive maybe than BUF04. This should be interesting to see how it plays out. I'm sure it will perform considerably better than the orginal.
The dual 826 was shown in Walt Jung's op-amp applications handbook -- the ad825 was suggested in the Adcom GFP-565 upgrade article which appeared in AX about 4 years ago.
WJ also showed use of a current feedback opamp -- the AD811 -- but the setup shown in the gif should perform a wee touch better.
There is absolutely plenty of room for the Super-Regulators.
Attenuator:
An externally hosted image should be here but it was not working when we last tested it.
Top -- plenty of room
An externally hosted image should be here but it was not working when we last tested it.
here's a spectrum -- vertical axis is 0.05 db/interval --
the tone controls are out (obviously) -- and a good thing too for they seem to be a complete bolixitis.
the tone controls are out (obviously) -- and a good thing too for they seem to be a complete bolixitis.
An externally hosted image should be here but it was not working when we last tested it.
Hi jackinnj,
Just think ..... people paid a lot of money to listen to that. I'm sure there was more than one fight over which preamp was better with this one included.
That explains the rather odd sound these had. I'm sure others have similar sonic evils. Still, at 0.05 dB / div, it isn't bad. It did seem to have a "brittle" sound to my ears. Pretty good for LM301's.
-Chris
Just think ..... people paid a lot of money to listen to that. I'm sure there was more than one fight over which preamp was better with this one included.
That explains the rather odd sound these had. I'm sure others have similar sonic evils. Still, at 0.05 dB / div, it isn't bad. It did seem to have a "brittle" sound to my ears. Pretty good for LM301's.
-Chris
I mad a mistake, the main IC in the line stage is an LF356H, not LM301 -- will correct the picture.
Here's a simulation of the phono stage RIAA performance -- with the schematic -- had to substitute a PN2222 for Q101 which is listed as "TZ-71":
and yesterday I sent out some printed circuit boards -- surface mount super-regulators -- +/- 18V on less than 9 square inches. i decided that cobbling up the boards from Old Colony with surface mount adapters was too much a clooge.
Here's a simulation of the phono stage RIAA performance -- with the schematic -- had to substitute a PN2222 for Q101 which is listed as "TZ-71":
An externally hosted image should be here but it was not working when we last tested it.
and yesterday I sent out some printed circuit boards -- surface mount super-regulators -- +/- 18V on less than 9 square inches. i decided that cobbling up the boards from Old Colony with surface mount adapters was too much a clooge.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- Crown IC-150A POOGE