I can not find any info on this amp at all anybody know its value....
Absolute monster working perfectly......
Everytime i google it it comes up with wrong one.....
Mine has got twin toroidals twin pairs of RIFA caps
12 2sa/2sc sanken...to3 per channel
Weighs the planet......
Contacted Bose even they sent me wrong schematic
Absolute monster working perfectly......
Everytime i google it it comes up with wrong one.....
Mine has got twin toroidals twin pairs of RIFA caps
12 2sa/2sc sanken...to3 per channel
Weighs the planet......
Contacted Bose even they sent me wrong schematic
bose
Hi thanks for reply about arcam going through the motions,other channel has blown its output while i was other engaged,,,
Apparently these amps had issues with the mosfet substitute as original went osolete,modifications had to be made,these have checked and all done on the board,,,lokks like ebay spares there it goes...
As for bose yeh i agree they make crap speakers anyway ..this amp
weighs in at nearly 30 kilo,s using bd(philips) pre and drivers generous heatsinks,78 vdc rails ,overheat protection......
Sounds very good actually was given to me for free as when you switched it on it would trip the main fuse box.....
Easy repair mains lead had been stretched and was shorting out.....
Going on ebay soon as not needed......
Regards
Hi thanks for reply about arcam going through the motions,other channel has blown its output while i was other engaged,,,
Apparently these amps had issues with the mosfet substitute as original went osolete,modifications had to be made,these have checked and all done on the board,,,lokks like ebay spares there it goes...
As for bose yeh i agree they make crap speakers anyway ..this amp
weighs in at nearly 30 kilo,s using bd(philips) pre and drivers generous heatsinks,78 vdc rails ,overheat protection......
Sounds very good actually was given to me for free as when you switched it on it would trip the main fuse box.....
Easy repair mains lead had been stretched and was shorting out.....
Going on ebay soon as not needed......
Regards
If it is the one I am thinking of it is a 1980s vintage PA amp (2U rack??), totally conventional circuit, weighs a ton, does maybe a KW total into 4 ohms per side and has a pin one problem.
Not worth much these days, too heavy, and a more modern amp will have better spares availability (And be lighter, more efficient, more reliable....).
They (Unlike the 802) were reasonably good amps in their day, but not competition for modern Lab Gruppen FP series or the like.
Regards, Dan.
Not worth much these days, too heavy, and a more modern amp will have better spares availability (And be lighter, more efficient, more reliable....).
They (Unlike the 802) were reasonably good amps in their day, but not competition for modern Lab Gruppen FP series or the like.
Regards, Dan.
The value is what somebody is willing to pay for it. Same for used cars. Not a blue book value.
I know this amp quite well, I own and worked on almost all Bose 1800 amplifiers from series 1 (nicknamed "The Porcupine" by the roadies) to series 6. Going onward from series 1 to 6, here's a short summary of their story.
- 1800 and 1801 series 1 were truly made by Bose, pro and consumer versions are identical apart from the added large VU-meters on the 1801. These are the true Bose amplifiers, designed and built with no compromise, and they were monsters back in 1973 (still are).
- 1800 series 2 : designed and made by Stage Accompany (Nederlands). To make a long story short, Bose contracted Stage Accompany to replace and improve over the previous pro model : lighter weight, no more agressive fins, about same power, forced ventilation, output protection relays etc. This amp can also be found under name SA900, just Google it.
- 1800 series 3 and 4 : 1986, that's where Detlev Daub's story begins. He is a student in computer science, and his friend Wolfgang Rink a plumber. Story was told by Detlev Daub himself : when Stage Accompany stopped production of the 1800-2 following their failure in distributing of Bose professional products in South Africa (big market) Bose Corp. decided to look elsewhere for contracting production of its pro amplifier. A small young German business, DAUB, was already producing power amplifiers for professional use and, in the words used by Detlev Daub, he said to himself "what Americans do, I am capable to do”. So in 1987 began production of the 1800 series 3 amplifier, quite similar to the 1800-2 except for a few details. Then this was followed by 1800-4, which in fact was a rebadged Daub D500E. Daub made around 20,000 amplifiers for Bose, and this fully mobilized its production capacity. Remember, DAUB was a very small company. Amplifiers bearing the name Daub were quickly forgotten by the market, and this sealed DAUB's fate. Death sentence sounded in 1994 when Bose Corp. decided to move its amplifiers production back in the United States. End of Daub.
- 1800 series V and VI : 21 years after release of first version here is the ultimate Bose 1800 avatar. Again it is quite singular. Right from the start, professional Bose amps had acquired a reputation of being reliable and robust work horses with a excellent audio quality. But relocating production can't be done in a fingers snap. Bose hadn't developed power electronics for a long time and there was now a plethora of brands and competing products in this sector. Also, rather than burn cash by creating a team of engineers dedicated to this project, once again Bose chooses to outsource the manufacturing of its amps and set its sights on Bob Carver. Ironically, this brilliant electronics engineer was, among other things, the creator of Phase Linear 400 and 700, the latter being one of the contemporary competitors for the Bose 1801. Bose therefore assembled Carver modules (and also supplied products to Carver such as wood finishing elements for Carver amps). The Bose 1800-6 is indeed a rebadged Carver PM1400, as PCB's silkscreens testify. The Bose 1600-6 corresponds to the Carver PM900.
That's all about the Bose pro amps story.
Thierry
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These came out of an 1801 back in the late 80’s - and I’ve never been able to track down what type they actually used in these things. There really were only two possibilities - the 2N6259 or 1B05 (or it’s 2N prototype number). Do you know which? It would be good to know once and for all what’s in my stash - I still have a handful of these, and I really don’t want to “waste” one by busting it open to look at the die.
My first 1801 was a complete gut job, where the one on the left came from. It was missing a channel entirely - along with the entire front panel - and less expensive to get working by building a new amp into. I used it from 1989 to 2004. The next ones I encountered just had blown transistors (little and big ones), and customers desperate for me to do something with them for less than the $1000 they were quoted from legitimate shops. They just got the usual replacements that I used for all of these amps at the time - MJ15024 outputs and MJE340/350 for predriver/VAS and worked fine. I never did find out what the original RCA102433 was.
My first 1801 was a complete gut job, where the one on the left came from. It was missing a channel entirely - along with the entire front panel - and less expensive to get working by building a new amp into. I used it from 1989 to 2004. The next ones I encountered just had blown transistors (little and big ones), and customers desperate for me to do something with them for less than the $1000 they were quoted from legitimate shops. They just got the usual replacements that I used for all of these amps at the time - MJ15024 outputs and MJE340/350 for predriver/VAS and worked fine. I never did find out what the original RCA102433 was.
Attachments
Same here, Bose kept their secrets... I suppose these transistors were selected or sorted in some way. I think I have a blown 102433 in a drawer, I should crack it open to examine the die.
I saved this 1800 from the graveyard and I have repaired and restored some others, including the 1801 I bought over 40 years ago, and which runs beautifully on MJ15024s.
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All of those old amps run beautifully on MJ15024’s. The only iffy one was the PL700 - but it’s still better than what was in there in the first place. 8 ohms only it’s fine. I wish I’d saved one of the dead 102433’s but the last one was probably 25 years ago. All the ones I have are still “good”. Just be nice to know what they’re really “good” for -just how hard they can be pushed.
Don’t know why I didn’t think of this earlier….
collector base capacitances @ zero bias:
RCA actually marked “2N6259” - 1700-1800 pF
RCA 68183 - 1800 pF
RCA102433 - 330-400 pF, which is more in line with 2N5240/BUX16/RCA1B05. It is a high SOA transistor, but the gain falls to the single digits at 5 amps. You need all 6 in parallel and the driver runs just as hard. They may have selected them for better hFE. When they select 2N6259’s it’s for voltage - rated VCEO is only 150 but they almost always take more.
collector base capacitances @ zero bias:
RCA actually marked “2N6259” - 1700-1800 pF
RCA 68183 - 1800 pF
RCA102433 - 330-400 pF, which is more in line with 2N5240/BUX16/RCA1B05. It is a high SOA transistor, but the gain falls to the single digits at 5 amps. You need all 6 in parallel and the driver runs just as hard. They may have selected them for better hFE. When they select 2N6259’s it’s for voltage - rated VCEO is only 150 but they almost always take more.
I have a couple of the 1st generation Bose 1801 amps and 4401 preamps that managed to find me, somehow.
I updated the 4401s following some postings Thierry did on another site. They play well and surprise the few that have heard them. The 1801s are still original and gathering dust, although there is a plan for an update on one or two.
If anyone needs some heavy packages....
I updated the 4401s following some postings Thierry did on another site. They play well and surprise the few that have heard them. The 1801s are still original and gathering dust, although there is a plan for an update on one or two.
If anyone needs some heavy packages....
it´s always interesting to learn the history behind famous-mysterious brands.
Meaning BOSE itself is famous, of course, but history behind who actually made them is incredible.
An end user has NO CLUE about all this, he just picks a large heavy cardboard box labelled "Bose" and carries it home.
Thanks for posting.
Meaning BOSE itself is famous, of course, but history behind who actually made them is incredible.
An end user has NO CLUE about all this, he just picks a large heavy cardboard box labelled "Bose" and carries it home.
Thanks for posting.
These are not Series I schematics, they're for series II. Here's the instructions manual.
Ahhh… the newer ones which I never got to work on switched over to the Sanken LAPT’s - as soon as they could by the looks of things. Good move. And seem to have adopted the “All PA amps look the same” topology of the BGW750 that everyone except QSC was using for the longest time. At the time their (and anybody else’s) pro stuff was out of my price range so I kept older stuff running.
After their consumer stuff started to take the nosedive, you could still get respectable pro equipment from them if you had the bucks. Eventually, their pro stuff started to falter - going smaller/cheaper/“better”. Those cute little line array (poles?) and subwoofers the size of a toaster oven don’t exactly qualify in my book. Can you even get an arena-size rig from them anymore, even if you did have 250 or 500 grand to spend? Harmon/JBL seems to be following the same model, just delayed in time somewhat. Took longer to acquire Crown and dBx and start turning it to junk. Not all junk yet, but given enough time it will be.
After their consumer stuff started to take the nosedive, you could still get respectable pro equipment from them if you had the bucks. Eventually, their pro stuff started to falter - going smaller/cheaper/“better”. Those cute little line array (poles?) and subwoofers the size of a toaster oven don’t exactly qualify in my book. Can you even get an arena-size rig from them anymore, even if you did have 250 or 500 grand to spend? Harmon/JBL seems to be following the same model, just delayed in time somewhat. Took longer to acquire Crown and dBx and start turning it to junk. Not all junk yet, but given enough time it will be.
Sorry .
