Cool, nice and cheap just a shame i missed the listing, Will have to keep hunting for one.
Oh okay, i read somewhere last night that DC was a issue at least its one less thing to worry about.
Are the 1800-IV built the same as the earlier versions? These seem to be a little more powerful and compact.
Last question being what class are they? I read Class A which would make sense but can't find a answer.
Oh okay, i read somewhere last night that DC was a issue at least its one less thing to worry about.
Are the 1800-IV built the same as the earlier versions? These seem to be a little more powerful and compact.
Last question being what class are they? I read Class A which would make sense but can't find a answer.
The MJ21194 or as one suggested earlier the MJ15024.
The service manual can be downloaded for free. Make sure to snag a copy, and confirm
the service bulletins/updates have been performed.
Right, it only has thermal protection. There are numerous add on protection circuits which can be had, if you want to add one.
You just need to pay attention to whatever power requirements the circuit might have.
Some of them have their own supply, and you can just tap directly off of the AC mains.
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They (Bose) used to have a power amp board exchange and also a power amp used refurb board replacement deal both for fixed fee.
There was one corner where a resistor would get really hot and burn the board...with the damage really obvious.
I wonder whether I still have a burned board or two around somewhere...but all my belongings are in boxes from moving.
There was one corner where a resistor would get really hot and burn the board...with the damage really obvious.
I wonder whether I still have a burned board or two around somewhere...but all my belongings are in boxes from moving.
Just about every amp that uses an op-amp input stage from that era suffers from that problem. A 5 watt sand box resistor with 2 watts dissipation will eventually fry the FR-4 and oxidize the trace and the solder joint. The resistoir needs to be mouted so it can get some air circulation and the joints should be re-soldered. It's even more critical than recapping.
Thanks for that bit of info on the resistor, think i remember reading about it else where.
How difficult would changing the frequency compensation be? I'd rather use better parts and and adjust the rest.
Are there any PCBs around anymore for it just in case i get a burn't one?
What would a decent condition Series 1 be worth?
Jake.
How difficult would changing the frequency compensation be? I'd rather use better parts and and adjust the rest.
Are there any PCBs around anymore for it just in case i get a burn't one?
What would a decent condition Series 1 be worth?
Jake.
Hey,
Sorry for opening up an old topic, but I have finally got hold of a 1800...and it has a few problems...
When a heavy bass track is played the power on neon cuts in and out depending on the frequency.
Has anyone come across this problem before? I haven't had a chance to strip it down yet and see if it's had any mods.
Looks to be in pretty good condition internally.
Jake.
Sorry for opening up an old topic, but I have finally got hold of a 1800...and it has a few problems...
When a heavy bass track is played the power on neon cuts in and out depending on the frequency.
Has anyone come across this problem before? I haven't had a chance to strip it down yet and see if it's had any mods.
Looks to be in pretty good condition internally.
Jake.
And you probably get a voltage sag at the wall socket every time the bass hits. There is probably more R and L in the 50 feet of Romex between it and the breaker panel than there is in the transformer primary (it's a monster). I've measured as low as 106 at the wall with amps in this power class. That will cause the NE2 to drop out for sure.
That is something i will have to measure is the volt drop, was expecting the breaker to trip when i switched it on.
Going to replace the Neons with LEDs and see what happens.
I'm looking to replace the C8, which is a ceramic disk capacitor 200pF 200V 10% with a Polystyrene capacitor but the old ones i seem to be able to find are these..
(CPS20/200) - 200pF 630V Polystyrene Capacitor Hifi Collective
Would a cap of this voltage cause as issues with any other components?
Going to replace the Neons with LEDs and see what happens.
I'm looking to replace the C8, which is a ceramic disk capacitor 200pF 200V 10% with a Polystyrene capacitor but the old ones i seem to be able to find are these..
(CPS20/200) - 200pF 630V Polystyrene Capacitor Hifi Collective
Would a cap of this voltage cause as issues with any other components?
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