Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 311
Default Tube Audio Amp question

Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark
  #2   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 23
Default Tube Audio Amp question

wrote:
Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark


try using 833 tubes. they are about 500 W each and the plates glow orange in
normal operation.


  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 9,560
Default Tube Audio Amp question

wrote:

Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark


Just run all your pairs in parallel. You can get them to current share
well enough with some uncoupled cathode resistance.

There are higher power tubes of course. 6L6=KT66, which iirc have a
bigger brother in KT88. Then there are serious power tubes.

Its quite possible to make your own. In fact if you're prepared to use
a bell jar and pump, its quite easy. Those valves could be funky as
well as groovy. Not many amps have to pump down to operate. Using bulb
filaments for emitters will make it very visual.


NT

  #4   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 68
Default Tube Audio Amp question


wrote:
Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark


Why so much power? Sounds like overkill to me. Build 50w monoblocks and
use a set of effecient horn type speakers (Klipsch or the like).
That'll be plenty loud. If you want to run a bazillion pairs of output
tubes in parallel....good luck finding an output transformer to match
the total plate impedance.

  #5   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,245
Default Tube Audio Amp question


"boardjunkie" wrote in message
oups.com...

Why so much power? Sounds like overkill to me. Build 50w monoblocks and
use a set of effecient horn type speakers (Klipsch or the like).
That'll be plenty loud. If you want to run a bazillion pairs of output
tubes in parallel....good luck finding an output transformer to match
the total plate impedance.


You hand wind one using the motor lams from an old 1 HP motor, and bus bar
copper hand insulated with cloth tape.







  #6   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 161
Default Tube Audio Amp question

On Fri, 03 Nov 2006 17:51:12 GMT, Homer J Simpson wrote:
"boardjunkie" wrote in message
oups.com...

Why so much power? Sounds like overkill to me. Build 50w monoblocks and
use a set of effecient horn type speakers (Klipsch or the like).
That'll be plenty loud. If you want to run a bazillion pairs of output
tubes in parallel....good luck finding an output transformer to match
the total plate impedance.


You hand wind one using the motor lams from an old 1 HP motor, and bus bar
copper hand insulated with cloth tape.


...during the peak of a lunar eclipse.
  #7   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,245
Default Tube Audio Amp question


wrote in message
...

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together?


Sure.


--
++++++++++++++++++++++++++++++++++++++++++++++++++ ++
+ Required crap appended to avoid restrictions imposed by brain +
+ damaged idiots.
+
+ Server Response: '441 Posting Failed (Rejected by POST filter)', +
+ Port: 119, Secure(SSL): No, Server Error: 441,
+
+ Error Number: 0x800CCCA9
+
++++++++++++++++++++++++++++++++++++++++++++++++++ ++



  #9   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,245
Default Tube Audio Amp question


"boardjunkie" wrote in message
ups.com...

Your post smacks of troll, but in the event you're serious, there's
always these:


Schematic:
http://www.ampslab.com/SCHEMATICS/CarverSilver7A.gif


Looks like the motor controller for a streetcar!






  #10   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 25
Default Tube Audio Amp question

wrote:

Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark


Trix used to make a cinema amplifier in the 50's. A pair of 813's with
nearly a Kv on the plate. If I recall they produced about 600 watts
into 100 volt line. The output trany was a toroid about 9 or 10 inches
in diameter, potted in a cast alloy case.

--
Baron:


  #11   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,924
Default Tube Audio Amp question

wrote:

Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark



Use a pair of 4CX1500 (or larger) tubes. ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
  #12   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 68
Default Tube Audio Amp question


Michael A. Terrell wrote:
Use a pair of 4CX1500 (or larger) tubes. ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Heh....yea. Transmitting tubes. I was gonna say a pair of 250TH.

  #13   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 150
Default Tube Audio Amp question

"Michael A. Terrell" ) writes:
wrote:

Back in the 60's I built a pair of amplifiers using four 6L6 output
tubes in push pull parallel mode. These were actually designed using
schematics from guitar amplifiers, and I used the output transformers
made for guitar amps. I ran these tubes to their limits by running
the highest power supply voltage as these tubes could handle. I ended
up with an extremely loud stereo, and was putting out enough power
that I once blew the glass out of a window. The sound was clear as a
bell too. I used some of the best and largest speakers I could get.

Well, these days I am old, retired now, and have had the urge to
design some tube amplifiers again. To me, they always sounded better
than semiconductor amps.

The 6L6 tubes were always my favorite tube. They were easy to get,
powerful and had a nice sound. But here's my question. Is it
possible to run EIGHT, or TWELVE, SIXTEEN of them together? I'd
assume the circuit would be to push pull parallel / Series. In other
words, run 2, 3, or more tubes in series TIMES FOUR (the push pull
parallel part of it). Is this possible?

I once figured that I was getting 140 watts RMS out of those four
6L6s, running everything at it's maximum. This time I'd like to go
for 280 watts or maybe 560 watts.......
Yeah, I already know getting an output transformer will be tough.
Probably need something custom made.

I might be old, but I still want to see if I can blow ALL the windows
out of the house, just to do it !!!!
I guess those of us who became adults during the 60's will never quite
give up the dreams. Somehow, a 1200 watt RMS system powered by a
total of 32 6L6 tubes and a wall of 18" woofers and horns just seems
groovy. (After I add another 200 Amp Breaker panel in the house), I
should be able to power these amps, along with a full spectrum, 10KW
color organ, strobes, blacklights, lava lamps, mirored balls, and of
course the original floating colored oil film kaleidoscope projection
system, while listening to the Woodstock soundtrack album on 12"
vinyl.

This could just be way farout, heavy, trippin, and totally groovy.

Mark



Use a pair of 4CX1500 (or larger) tubes. ;-)

Not that any of this is a repair issue, but if you're going to
use those, you might as well go for watercooled tubes. Get
rid of that fan noise, and why not be out of the ordinary.

Michael

  #14   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,245
Default Tube Audio Amp question


"Michael Black" wrote in message
...

Not that any of this is a repair issue, but if you're going to
use those, you might as well go for watercooled tubes. Get
rid of that fan noise, and why not be out of the ordinary.


Real men use 200 amp SCRs.



--
++++++++++++++++++++++++++++++++++++++++++++++++++ ++
+ Required crap appended to avoid restrictions imposed by brain +
+ damaged idiots.
+
+ Server Response: '441 Posting Failed (Rejected by POST filter)', +
+ Port: 119, Secure(SSL): No, Server Error: 441,
+
+ Error Number: 0x800CCCA9
+
++++++++++++++++++++++++++++++++++++++++++++++++++ ++





  #15   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,469
Default Tube Audio Amp question

Homer J Simpson spake thus:

"Michael Black" wrote in message
...

Not that any of this is a repair issue, but if you're going to
use those, you might as well go for watercooled tubes. Get
rid of that fan noise, and why not be out of the ordinary.


Real men use 200 amp SCRs.


Water-cooled?


--
Just as McDonald's is where you go when you're hungry but don't really
care about the quality of your food, Wikipedia is where you go when
you're curious but don't really care about the quality of your knowledge.

- Matthew White's WikiWatch (http://users.erols.com/mwhite28/wikiwoo.htm)


  #16   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,245
Default Tube Audio Amp question


"David Nebenzahl" wrote in message
s.com...

Real men use 200 amp SCRs.


Water-cooled?


Mercury!


--
++++++++++++++++++++++++++++++++++++++++++++++++++ ++
+ Required crap appended to avoid restrictions imposed by brain +
+ damaged idiots.
+
+ Server Response: '441 Posting Failed (Rejected by POST filter)', +
+ Port: 119, Secure(SSL): No, Server Error: 441,
+
+ Error Number: 0x800CCCA9
+
++++++++++++++++++++++++++++++++++++++++++++++++++ ++





  #17   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4
Default Tube Audio Amp question


You'd want to switch tubes to maybe a higher power pentode like a 6146.
There was someone experimenting with a 6 tube 1500 watt amp but I don't
remember what tubes he used just that the filiment current was around 10
amps.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794


A higher power tube does seem to make more sense than combining 36 smaller
ones. But unless I'm mistaken, the 6146 is rated for 25 watt plate
dissipation, the same as the 6L6.


  #18   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 23
Default Tube Audio Amp question


This could just be way farout, heavy, trippin, and totally groovy.

Mark



Use a pair of 4CX1500 (or larger) tubes. ;-)


3CX2500F3 even?... problem is the forced air cooling is so noisy.


  #19   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 28
Default Tube Audio Amp question

Meat Plow wrote:
On Sat, 04 Nov 2006 19:03:16 -0800, Blake Has Frothed:

You'd want to switch tubes to maybe a higher power pentode like a 6146.
There was someone experimenting with a 6 tube 1500 watt amp but I don't
remember what tubes he used just that the filiment current was around 10
amps.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

A higher power tube does seem to make more sense than combining 36 smaller
ones. But unless I'm mistaken, the 6146 is rated for 25 watt plate
dissipation, the same as the 6L6.


Must have read the tube data wrong or the data I was reading was a typo.

Some else suggested using an 813. I can't recall the site but someone
built a 1kw audio amp using them. This guy was a bit on eccentric side if
I recall correctly.



If you live in the Portland Oregon (US) area (I won't ship this thing) I
have an 813 for sale, comes with a ceramic base/socket. Lit the
filaments up for about 10 minutes that is all that it has ever done.
Looks brand new, would probably act brand new as well.

$10.00 US


-Landon

  #20   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,924
Default Tube Audio Amp question

TimPerry wrote:


This could just be way farout, heavy, trippin, and totally groovy.

Mark



Use a pair of 4CX1500 (or larger) tubes. ;-)


3CX2500F3 even?... problem is the forced air cooling is so noisy.



Not if you build it right. The fans are usually vented outside the
building when used for AM broadcast transmitters. I know of several
stations where the air cooled transmitter is close enough for the
operator to see the meters while they are ion the air, yet you can't
hear them in the control room.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida


  #21   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 23
Default Tube Audio Amp question

Michael A. Terrell wrote:
TimPerry wrote:


This could just be way farout, heavy, trippin, and totally groovy.

Mark


Use a pair of 4CX1500 (or larger) tubes. ;-)


3CX2500F3 even?... problem is the forced air cooling is so noisy.



Not if you build it right. The fans are usually vented outside the
building when used for AM broadcast transmitters. I know of several
stations where the air cooled transmitter is close enough for the
operator to see the meters while they are ion the air, yet you can't
hear them in the control room.


but not IN the studio. the newer solid state stuff is a lot quiter but still
has fans running.

have you noticed that as power amps are now being made bigger and bigger
that there are now speaker systems bening made that claim to handle the
power? for example the peavey QW series.


  #22   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,924
Default Tube Audio Amp question

TimPerry wrote:

Michael A. Terrell wrote:
TimPerry wrote:


This could just be way farout, heavy, trippin, and totally groovy.

Mark


Use a pair of 4CX1500 (or larger) tubes. ;-)

3CX2500F3 even?... problem is the forced air cooling is so noisy.



Not if you build it right. The fans are usually vented outside the
building when used for AM broadcast transmitters. I know of several
stations where the air cooled transmitter is close enough for the
operator to see the meters while they are ion the air, yet you can't
hear them in the control room.


but not IN the studio. the newer solid state stuff is a lot quiter but still
has fans running.

have you noticed that as power amps are now being made bigger and bigger
that there are now speaker systems bening made that claim to handle the
power? for example the peavey QW series.


Sure, they are extremely inefficient. I used some very efficient
music grade drivers and horns back in the '70s that could be heard
clearly over five miles away, with a 65 watt amp. When I built a 70 watt
transistor amp in the late '60s, the largest paper speaker I could find
was 20 watts.

Have you ever seen the insides of one of the Harris digital AM
broadcast transmitters? WQBQ, The last station I visited that had one
in service had a pile of badly damaged output modules from lightning
strikes. I dismantled and moved their original 5 KW Gates BC-5
transmitter to WLBE in leesburg, Florida.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
  #23   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 23
Default Tube Audio Amp question

Michael A. Terrell wrote:
TimPerry wrote:

Michael A. Terrell wrote:
TimPerry wrote:


This could just be way farout, heavy, trippin, and totally
groovy.

Mark


Use a pair of 4CX1500 (or larger) tubes. ;-)

3CX2500F3 even?... problem is the forced air cooling is so noisy.


Not if you build it right. The fans are usually vented outside
the building when used for AM broadcast transmitters. I know of
several stations where the air cooled transmitter is close enough
for the operator to see the meters while they are ion the air, yet
you can't hear them in the control room.


but not IN the studio. the newer solid state stuff is a lot quiter
but still has fans running.

have you noticed that as power amps are now being made bigger and
bigger that there are now speaker systems bening made that claim to
handle the power? for example the peavey QW series.


Sure, they are extremely inefficient. I used some very efficient
music grade drivers and horns back in the '70s that could be heard
clearly over five miles away, with a 65 watt amp. When I built a 70
watt transistor amp in the late '60s, the largest paper speaker I
could find was 20 watts.

Have you ever seen the insides of one of the Harris digital AM
broadcast transmitters?


not yet. i was given a BE digital to install.

WQBQ, The last station I visited that had one
in service had a pile of badly damaged output modules from lightning
strikes.


probably from the power lines, unless thier lightning prot was screwed.

I dismantled and moved their original 5 KW Gates BC-5
transmitter to WLBE in leesburg, Florida.


i need an audio section for a BC-5 - it shoots flames out center hole where
the power resistors join.




  #24   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,924
Default Tube Audio Amp question

TimPerry wrote:

Michael A. Terrell wrote:
TimPerry wrote:

Michael A. Terrell wrote:
TimPerry wrote:


This could just be way farout, heavy, trippin, and totally
groovy.

Mark


Use a pair of 4CX1500 (or larger) tubes. ;-)

3CX2500F3 even?... problem is the forced air cooling is so noisy.


Not if you build it right. The fans are usually vented outside
the building when used for AM broadcast transmitters. I know of
several stations where the air cooled transmitter is close enough
for the operator to see the meters while they are ion the air, yet
you can't hear them in the control room.

but not IN the studio. the newer solid state stuff is a lot quiter
but still has fans running.

have you noticed that as power amps are now being made bigger and
bigger that there are now speaker systems bening made that claim to
handle the power? for example the peavey QW series.


Sure, they are extremely inefficient. I used some very efficient
music grade drivers and horns back in the '70s that could be heard
clearly over five miles away, with a 65 watt amp. When I built a 70
watt transistor amp in the late '60s, the largest paper speaker I
could find was 20 watts.

Have you ever seen the insides of one of the Harris digital AM
broadcast transmitters?


not yet. i was given a BE digital to install.

WQBQ, The last station I visited that had one
in service had a pile of badly damaged output modules from lightning
strikes.


probably from the power lines, unless thier lightning prot was screwed.


Probably started as EMP damage from repeated lightning strikes on the
towers. It is in an part of Florida that can exceed 1000 strikes per
hour, and lots of those are on towers. The building is old precast
concrete and cement blocks. The newer transmitter was installed by the
station's engineer. From the way things looked he spent all of an hour
connecting the power, antenna and audio to it. He used a piece of 4"
copper strap, but the joints were really crappy.



I dismantled and moved their original 5 KW Gates BC-5
transmitter to WLBE in leesburg, Florida.


i need an audio section for a BC-5 - it shoots flames out center hole where
the power resistors join.


I can ask the next time I hear from their engineer, or you can call
the station and see if they still have what you need. In fact, I think
they just retired the other BC-5, and may have a complete transmitter
for sale, as well. Believe it or not, but their engineer doesn't have
an e-mail address. I have tried for years to get him to at least get a
free account that he can check from the different stations. WLBE
doesn't seem to have a website, either.

http://yellowpages.superpages.com/ffile.jsp?N=wlbe&STYPE=S&L=FL&R=N&LID=0087308945&d isplay=1

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rivera M60 tube amp question Richard Rasker Electronics Repair 4 September 29th 05 04:51 PM
Boiler Tube Roller Question [email protected] Metalworking 8 December 11th 04 06:45 PM
Magnavox TV model RS4254WA02, Ch. 19C506 no audio (repost) Lenny Electronics Repair 1 June 11th 04 05:04 PM
Tech Review: Victor's (8liners/Genao) Replacement Arcade RGB Monitor Chassis (LONG) Pac-Fan Electronics Repair 22 November 26th 03 12:56 PM
metal tubes Allan Adler Metalworking 7 September 26th 03 04:30 AM


All times are GMT +1. The time now is 03:29 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"