WOPL conversions on Dual 500?

grapplesaw

grapplesaw

Veteran and General Yakker
#41
Joined
Aug 13, 2014
Messages
2,775
Location
Vancouver
Tagline
---
#41
laatsch55 said:
Which wire Glen? And I was thinking about going with the 120 rail voltage 500 in the 700. With the MJ21196's , they might hold up....I've thought about it too. That's what led to the monster mono idea. The idea behind the monster monos was to drive a low ohm load all day long at hi power levels. The power supplies on the monsters are going to be built so I can add 2 more toroids per channel if need be...

If you put a 700 tranny in a 500 you would at least be able to spread a low ohm load over more outputs..
Click to expand...
The wire I am talking about is coming out of the inlet supply side wires on the transformer The color is gray in the unit I am rebuilding but varies in color in different units. It is capped off with a Teflon cap and tie rap
 
laatsch55

laatsch55

Administrator,
Staff member
#43
Joined
Jan 14, 2011
Messages
74,774
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#43
After testing into 4 ohms at 775, I'm confident a 700 would do 350 into 2. I will answer that question in the near future. My load cell can do 2 ohms at 1,000 watta a channel...
 
laatsch55

laatsch55

Administrator,
Staff member
#44
Joined
Jan 14, 2011
Messages
74,774
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#44
Gepetto said:
It is not 120V it is 2X 120 volts (240V) that you should be concerned about. At 240V Vce, the MJ21196 will tolerate 600mA per device for 1 second at a Tj of 200C peak.

The original PL909 would have been toast long before that.
Click to expand...
Sooooooo to achieve 700 watts per channel into 2 ohms how many output devices would be required? And do you count the negative and positive devices as equally sharing the total load?
 
grapplesaw

grapplesaw

Veteran and General Yakker
#45
Joined
Aug 13, 2014
Messages
2,775
Location
Vancouver
Tagline
---
#45
Gepetto said:
It is not 120V it is 2X 120 volts (240V) that you should be concerned about. At 240V Vce, the MJ21196 will tolerate 600mA per device for 1 second at a Tj of 200C peak.

The original PL909 would have been toast long before that.
Click to expand...

Looking at the parts list the d500 uses tp9054 in quasi comp setup with the RCA410
 
Gepetto

Gepetto

Administrator
Staff member
#47
Joined
May 15, 2011
Messages
13,915
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#47
laatsch55 said:
Sooooooo to achieve 700 watts per channel into 2 ohms how many output devices would be required? And do you count the negative and positive devices as equally sharing the total load?
Click to expand...
700W into 2 ohms is operating in a area of the SOA where the devices can theoretically do about 5A per device for 10msec or 5 x 5A = 25A for the bank. This is in a condition where the peak current is 26.5A so you are living a bit beyond the edge. To give you proper margin you should be running at least 7 devices in parallel. With that you will have to cool it very well to sustain continuous wave output at those levels. At those output levels, I doubt you would hear the fans spinning or anything else for that matter because you would have blown out your eardrums and your voice coils.
 
Gepetto

Gepetto

Administrator
Staff member
#48
Joined
May 15, 2011
Messages
13,915
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#48
Gepetto said:
700W into 2 ohms is operating in a area of the SOA where the devices can theoretically do about 5A per device for 10msec or 5 x 5A = 25A for the bank. This is in a condition where the peak current is 26.5A so you are living a bit beyond the edge. To give you proper margin you should be running at least 7 devices in parallel. With that you will have to cool it very well to sustain continuous wave output at those levels. At those output levels, I doubt you would hear the fans spinning or anything else for that matter because you would have blown out your eardrums and your voice coils.
Click to expand...
And to answer your other question that is 14 output devices per channel, and does not include the pre-driver.
 
laatsch55

laatsch55

Administrator,
Staff member
#49
Joined
Jan 14, 2011
Messages
74,774
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#49
Gepetto said:
700W into 2 ohms is operating in a area of the SOA where the devices can theoretically do about 5A per device for 10msec or 5 x 5A = 25A for the bank. This is in a condition where the peak current is 26.5A so you are living a bit beyond the edge. To give you proper margin you should be running at least 7 devices in parallel. With that you will have to cool it very well to sustain continuous wave output at those levels. At those output levels, I doubt you would hear the fans spinning or anything else for that matter because you would have blown out your eardrums and your voice coils.
Click to expand...
And running out of power supply long before that....
 
laatsch55

laatsch55

Administrator,
Staff member
#50
Joined
Jan 14, 2011
Messages
74,774
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#50
grapplesaw said:
The wire I am talking about is coming out of the inlet supply side wires on the transformer The color is gray in the unit I am rebuilding but varies in color in different units. It is capped off with a Teflon cap and tie rap
Click to expand...
I've wondered about that wire myself but never stuck a meter on it....
 
grapplesaw

grapplesaw

Veteran and General Yakker
#51
Joined
Aug 13, 2014
Messages
2,775
Location
Vancouver
Tagline
---
#51
Last edited:
Gepetto

Gepetto

Administrator
Staff member
#52
Joined
May 15, 2011
Messages
13,915
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#52
grapplesaw said:
Lee did I read somewhere that you had a carver PT2400
It put out 1500 watts at 2 ohms per channel

Here are the secs
http://www.audiorama-berlin.de/pdf/pt-manual.pdf
Click to expand...
It has a switched cascode output stage...different topology.

The heat is the big problem and has to be dissipated somewhere. That is why the big PA rigs have moved to switchmode operation. Fidelity is not great but nobody notices in a football stadium.
 
Last edited:
grapplesaw

grapplesaw

Veteran and General Yakker
#53
Joined
Aug 13, 2014
Messages
2,775
Location
Vancouver
Tagline
---
#53
Gepetto said:
It has a switched cascade output stage...different topology.

The heat is the big problem and has to be dissipated somewhere. That is why the big PA rigs have moved to switchmode operation. Fidelity is not great but nobody notices in a football stadium.
Click to expand...
Ok. That makes sense Joe
 
Northwinds

Northwinds

Veteran and General Yakker
#58
Joined
Mar 18, 2013
Messages
7,560
Location
Coventry, CT
Tagline
Fondler errrr... fan of all Nav's avatars
#58
I was just reading an old thread on some board that was harping the old Flame Linears but many were standing up for them also

I did find a reference to the 700s having a BiPolar 140v power supply so is the extra wire somehow related to that??? 140v transformer is some major power waiting to happen eh?
 
You must log in or register to reply here.
Top