Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




27 posts

Geek


# 257366 29-Sep-2019 11:29
Send private message quote this post

Having trouble getting the Amps to work at the moment I have the preamp RCA left going to left amp mono connection and the RCA right going to the right amp mono connection I then have used the top mono outputs left + right - out to speaker is this the right way to connect??

I have 2 XJ300ST amps one for each speaker bridged to get 170w

View this topic in a long page with up to 500 replies per page Create new topic
 1 | 2
6974 posts

Uber Geek

Trusted
Subscriber

  # 2326638 29-Sep-2019 11:42
Send private message quote this post

Hi that sounds correct basically use the left input rca and the speaker across te L+ and R- but I would expect a manual switch somewhere purhaps inside to finish the signal routing.

Cyril

6974 posts

Uber Geek

Trusted
Subscriber

  # 2326641 29-Sep-2019 11:47
Send private message quote this post

OK found the manual, you need to connect the left preamp out to both l and r inputs of the power amp, so a Y splitter

Cyril

 
 
 
 




27 posts

Geek


  # 2326647 29-Sep-2019 11:57
Send private message quote this post

Awesome thanks am yet to try this so will let you know how it goes I wasnt getting any sound at all how it was

6974 posts

Uber Geek

Trusted
Subscriber

  # 2326648 29-Sep-2019 11:57
Send private message quote this post

Also you say you want 170w if that the case just feed the L channel and speaker to just L channel terminals, but to get 300w, ie Bridge connect as I mentioned above.

Cyril



27 posts

Geek


  # 2326672 29-Sep-2019 12:28
Send private message quote this post

I am using them for 8 ohm KEF Q950 speakers. XJ300ST specs says 170w 8 ohm mono and 4 ohm mono which is 300w will this give the speakers 300w or does it somehow know they are 8 ohm

6974 posts

Uber Geek

Trusted
Subscriber

  # 2326680 29-Sep-2019 12:49
One person supports this post
Send private message quote this post

Hi, power is an ability, not an imposed delivery, in bridge mode you are technically able to deliever around 600w into an 8ohm load, but something will break before you get there, most likely the voice coils and crossover.

 

Cyril




27 posts

Geek


  # 2326726 29-Sep-2019 13:53
Send private message quote this post

Cool thanks so I just tried splitters and still no sound what am I missing something simple? The green light is on the amps so there is power there really strange it all seems good but the amps just wont go???

 
 
 
 


1912 posts

Uber Geek


  # 2327013 30-Sep-2019 09:55
Send private message quote this post

When I bridged my homemade amp years back.....
For bridged mode, the input has to be mono & the input into one of the channels needs to be inverted.
I made a inverting opamp circuit for that
Then put the speaker across the L+ and the R+ (from memory)

 

Your digital amp may be wired differently than usual . -R and -L are usually the same connection , so I cant see why you would use -R for the spkr in bridge mode. May being something strange
with the design of your amp .

 

also , if you have a 8ohm speaker, each ~amp~ (channel) will see a 4ohm load . So check the max rating into 4ohm for the amp.

 

Regardless , you'll blow the ring out of the speakers
Speakers are often rated for max power of the voicecoils , not rated for the max the speaker can mechanically cope with.

 

even 170W is far to much in any home.
100W is ear bleeding volume ... IF you speakers can actually cope with that power . And they cant , not mechanically.

Power & logrithms . Means you need 10x the power to double the volume as we hear it. Your speakers wont cope .
10w is plenty. Thats all you need in the av home. 

 

 


6974 posts

Uber Geek

Trusted
Subscriber

  # 2327020 30-Sep-2019 10:03
Send private message quote this post

Hi, if both channels are driven in phase, then using L+ and R- will make up for that.

 

I have a set of Kef 700Q's driven from a 100w/ch Yamaha, could not imagine it pushed to full throttle, so yes not sure why so much power is needed.

 

Cyril


1239 posts

Uber Geek


  # 2327084 30-Sep-2019 12:42
Send private message quote this post

to add to the above...

 

bridged amps usually sound worse.

 

 




27 posts

Geek


  # 2327251 30-Sep-2019 18:44
Send private message quote this post

Thanks. the speakers say 15w to 200w I would of thought you could give them 200w and not blow anything?

22525 posts

Uber Geek

Trusted
Subscriber

  # 2327258 30-Sep-2019 18:56
Send private message quote this post

1101:

 

Your digital amp may be wired differently than usual . -R and -L are usually the same connection , so I cant see why you would use -R for the spkr in bridge mode. May being something strange
with the design of your amp .

 

 

Usual is that one channel is inverted and the red terminal is ground, black terminal is driven on that side. Means that when in stereo the 2 channels are pulling from opposite rails most of the time and can be bridged without any additional parts.





Richard rich.ms

6974 posts

Uber Geek

Trusted
Subscriber

  # 2327273 30-Sep-2019 19:10
Send private message quote this post

Hi yes you could give them 200w, but if this is in a suburban setting I think you have got the formula wrong.

Cyril



27 posts

Geek


  # 2327292 30-Sep-2019 20:12
Send private message quote this post

Just wanted a slighty more powerful amp as preamp is only 80w probably enough at lower volume but was hoping these amps would get them rocking a bit more

5575 posts

Uber Geek


  # 2327296 30-Sep-2019 20:36
Send private message quote this post

Preamp would normally be in milliwatts, not 80 watts. If you've fed 80 watts into the input stage of that amp, it may be cooked.


 1 | 2
View this topic in a long page with up to 500 replies per page Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Arlo unveils its first video doorbell
Posted 21-Oct-2019 08:27


New Zealand students shortlisted for James Dyson Award
Posted 21-Oct-2019 08:18


Norton LifeLock Launches Norton 360
Posted 21-Oct-2019 08:11


Microsoft New Zealand Partner Awards results
Posted 18-Oct-2019 10:18


Logitech introduces new Made for Google keyboard and mouse devices
Posted 16-Oct-2019 13:36


MATTR launches to accelerate decentralised identity
Posted 16-Oct-2019 10:28


Vodafone X-Squad powers up for customers
Posted 16-Oct-2019 08:15


D Link ANZ launches EXO Smart Mesh Wi Fi Routers with McAfee protection
Posted 15-Oct-2019 11:31


Major Japanese retailer partners with smart New Zealand technology IMAGR
Posted 14-Oct-2019 10:29


Ola pioneers one-time passcode feature to fight rideshare fraud
Posted 14-Oct-2019 10:24


Spark Sport new home of NZC matches from 2020
Posted 10-Oct-2019 09:59


Meet Nola, Noel Leeming's new digital employee
Posted 4-Oct-2019 08:07


Registrations for Sprout Accelerator open for 2020 season
Posted 4-Oct-2019 08:02


Teletrac Navman welcomes AI tech leader Jens Meggers as new President
Posted 4-Oct-2019 07:41


Vodafone makes voice of 4G (VoLTE) official
Posted 4-Oct-2019 07:36



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.