No one will believe this one. While cleaning out my dad's electronics room I found 2 Crown DC300a in factory sealed cartons. I opened one flap of one of them to see for sure what was inside and there was the manual so have not gone any further. These had to be form 1975-76.
My concerns are age and condition of capacitors. Also would I be better off selling these than opening them up and devaluing the amps.
Sourcing the power caps may be pricey. Crown may still have them but at what cost?
Looking for some direction on this one.
FYI...,they were stored in a warm dry shop all these years.
My concerns are age and condition of capacitors. Also would I be better off selling these than opening them up and devaluing the amps.
Sourcing the power caps may be pricey. Crown may still have them but at what cost?
Looking for some direction on this one.
FYI...,they were stored in a warm dry shop all these years.
You should just seal them back up and send them to me as quickly as possible...
Those should be fairly easy to recap without harming anything, use caution when starting up for the first time... Parts would be newer replacements of equal or better quality, would not typical to use an oem replacement for most equipment.
Eye opening story too!
Those should be fairly easy to recap without harming anything, use caution when starting up for the first time... Parts would be newer replacements of equal or better quality, would not typical to use an oem replacement for most equipment.
Eye opening story too!
If you do decide to sell them, don't open the boxes, it will reduce their value.
You can buy a normal used Crown cheaply enough if you want one, and
refurbish it instead.
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Virgin unopened unused condition would likely fetch a very handsome price from a suitably rabid collector !.
If you are to run them up, I recommend/insist you use a 'bulb limiter' and monitor bias currents and DC offsets during initial power up, initial long term idling and power cycling.
I would also prophylactically clean/treat switches and pots at this stage.
Let the amp soak test idle for a day or two to allow caps to reform and early failures to show up before applying signal.
Once all is good, run it into speakers at low level on 'easy/melodic' music for some hours before incrementally running at higher levels.....don't be tempted to run Jimi Hendrix full blast just yet.
During this run up process you may find that the amp sounds 'all wrong' until a particular instantaneous peak level has been achieved at which the amp immediately 'relaxes' and sounds more like it should when subsequently run at slightly lower level.
So, in careful stages raise the level up to momentary clip without inducing gross overload and you will have a good sounding amp evermore....within the limits of course of this now very dated but 'classic' and hallmark design.
The above advice may seem strange, but I have observed this behavioural change in many many amplifiers on the bench either newly constructed or having been just repaired and majorly reworked....ie majorly/blanket resoldered.
Hitting an amp with full power 'noise' type music from the word go can leave an imprint IME.
Just sayin'.
Dan.
If you are to run them up, I recommend/insist you use a 'bulb limiter' and monitor bias currents and DC offsets during initial power up, initial long term idling and power cycling.
I would also prophylactically clean/treat switches and pots at this stage.
Let the amp soak test idle for a day or two to allow caps to reform and early failures to show up before applying signal.
Once all is good, run it into speakers at low level on 'easy/melodic' music for some hours before incrementally running at higher levels.....don't be tempted to run Jimi Hendrix full blast just yet.
During this run up process you may find that the amp sounds 'all wrong' until a particular instantaneous peak level has been achieved at which the amp immediately 'relaxes' and sounds more like it should when subsequently run at slightly lower level.
So, in careful stages raise the level up to momentary clip without inducing gross overload and you will have a good sounding amp evermore....within the limits of course of this now very dated but 'classic' and hallmark design.
The above advice may seem strange, but I have observed this behavioural change in many many amplifiers on the bench either newly constructed or having been just repaired and majorly reworked....ie majorly/blanket resoldered.
Hitting an amp with full power 'noise' type music from the word go can leave an imprint IME.
Just sayin'.
Dan.
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You will get nothing for them here.
I wonder if their is something significant about those two amps...do you have serial numbers ?.
Perhaps Crown would be interested in them for museum purposes ?.
I would look around the net...you will find brand loyalty nutter sites for every make and early Crown could be much sought after especially with the provenance of this pair....bragging rights like this just don't happen everyday.
Dan.
I wonder if their is something significant about those two amps...do you have serial numbers ?.
Perhaps Crown would be interested in them for museum purposes ?.
I would look around the net...you will find brand loyalty nutter sites for every make and early Crown could be much sought after especially with the provenance of this pair....bragging rights like this just don't happen everyday.
Dan.
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I could open the boxes to get serial numbers off the manuals but only opened one flap of one to see what was inside. No serial numbers on box. I just read that Crown is closing or has closed in Elkhart, Indiana. Supposedly Harmon was bought by Samsung.
I may try ebay but the asking price is still a question. I would hate to see them go for a very low price if they are worth a lot. If my dad were alive it would be easier.
I may try ebay but the asking price is still a question. I would hate to see them go for a very low price if they are worth a lot. If my dad were alive it would be easier.
They were an instrumentation amp and dangerous around speakers because they will produce DC as long as input has it. If the zero is off they will produce DC out with a centered input. Good for driving actuators like engine throttles and the like. No DC detect on speaker output and shutdown, like a proper bar band amp.
Not a great sound and has an obsolete op amp IC at the core, which is difficult to replace with something more musical. Wrong pinout. There was a used DC300 on e-bay last week, they weren't asking much. There is your base price, a little above that since yours are NOS. Protect your nice antique boxes with a box outside them if you ship it.
You could pull the boards and use the Power Supply heat sink and fan for something modern, but that applies to a lot of old amps on e-bay. Buy something else if you want to experiment. I just bid $20 on a blown 400 W band amp for example, planning to drive the output transistors with a high powered op amp and delete some stages.
Not a great sound and has an obsolete op amp IC at the core, which is difficult to replace with something more musical. Wrong pinout. There was a used DC300 on e-bay last week, they weren't asking much. There is your base price, a little above that since yours are NOS. Protect your nice antique boxes with a box outside them if you ship it.
You could pull the boards and use the Power Supply heat sink and fan for something modern, but that applies to a lot of old amps on e-bay. Buy something else if you want to experiment. I just bid $20 on a blown 400 W band amp for example, planning to drive the output transistors with a high powered op amp and delete some stages.
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DC300a amplifiers will often not start up properly when powered through a light bulb box. They more often than not latch up.
The Crown plant in Elkhart has closed and more importantly the competant service techs are gone. There is one remainder company AE Techron on Indiana that will service them. Cost can be $300.00 each.
The plant closure was all Harman not Samsung inspired.
eBay them is what I would do.
The Crown plant in Elkhart has closed and more importantly the competant service techs are gone. There is one remainder company AE Techron on Indiana that will service them. Cost can be $300.00 each.
The plant closure was all Harman not Samsung inspired.
eBay them is what I would do.
Sell 'em.
I have sold the PCB and transistors via EBay on 3 occasions -- there are some pretty rabid collectors out there and the IC-chip is unobtanium. it always seemed to me that the heat sinks were for Class-B operation.
I have retrofitted one with an LM4702 and lateral mosfets (LM4702 is now EOL). Pix are somewhere here on diyaudio.
I have sold the PCB and transistors via EBay on 3 occasions -- there are some pretty rabid collectors out there and the IC-chip is unobtanium. it always seemed to me that the heat sinks were for Class-B operation.
I have retrofitted one with an LM4702 and lateral mosfets (LM4702 is now EOL). Pix are somewhere here on diyaudio.
Hi everyone,
I spoke to a lady at Crown in Elkhart today. They have closed. Parts are available
from a California location. Manufacturing of amplifiers has been moved to..... get this...Tijuana,Mexico.
I guess I now have a Taco 300A made by Herb Alpert and his....you know the rest. On top of that, Samsung now owns Harmon........
What next?
I spoke to a lady at Crown in Elkhart today. They have closed. Parts are available
from a California location. Manufacturing of amplifiers has been moved to..... get this...Tijuana,Mexico.
I guess I now have a Taco 300A made by Herb Alpert and his....you know the rest. On top of that, Samsung now owns Harmon........
What next?
After careful consideration and the advice of this talented group I am going to list these amps on ebay ahd see what happens.
I looked at Crown's website and couldn't find any location for them in California. The large caps are my main concern for size and shape. Caps have shrunk in size over the years so that is my problem. If they do not sell I will investigate further.
I looked at Crown's website and couldn't find any location for them in California. The large caps are my main concern for size and shape. Caps have shrunk in size over the years so that is my problem. If they do not sell I will investigate further.
I sold some NOS Mallory's to a fella who had a DC300. The OEM Sangamo's in his were shot.
Almost every Crown amp I have taken in benefitted from a soak of the front panel with a solution of borax and water -- removes the nicotine and other organic smoke.
Is there a good source for fresh power supply caps?
If I were to go through these amps I would think recapping would be fairly straight forward being they are in sealed boxes. I can't see there being any component issues besides caps.
They may have design issues as some have indicated but a dirty pot is about all besides caps...am I missing something?
If I were to go through these amps I would think recapping would be fairly straight forward being they are in sealed boxes. I can't see there being any component issues besides caps.
They may have design issues as some have indicated but a dirty pot is about all besides caps...am I missing something?
If they have been sitting that long, the bias pot wiper may be oxidized. That is, it will need to be "exercised" by setting the bias to zero (or as low as it will go) and re-set it per service manual. If you are going to sell them, leave that exercise to the buyer - and a serious one will know to at least check it.
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