Re: [Drakelist] L4 vs. L4B
Mike - Couple of things. 1. The L-4 never was sold with 4-400s. I assume you mean 3-400Zs. 2. Electrically, yes, you can replace the 3-400s with 3-500Zs. The problem is that the '500s are a little taller and won't fit in some of the chimneys Drake supplied. There really isn't any reason to replace 'good' 3-400s with 3-500s as long as you stay within the original power specs. This is about the limit of the power supply anyway. Yes, you can get close to today's legal limit, if you really need that one quarter of an S-Unit increase. The main 'significant' difference between the two is that the B moved the ALC level control from the rear panel, and made it a 'push-pull' switch control to put the amplifier in standby. Pushing the knob IN takes the amplifier off line without turning it off. With the L-4, you have to switch the AC power off to bypass the amplifier. The 3-400/500Zs are 'instant on' tubes so not an operating problem, but you could argue about turning the amp on and off multiple times. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com m coffey wrote: Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4 vs. L4B
Of all the ham gear I've owned and operated, the position of the ALC switch on my L-4B for 'standby / operate' seems the most counter-intuitive function to me - and one I screw up more times than I care to admit. From just a human factors perspective, pushing the switch in would logically mean 'on' or 'in-line', and pulling it out would mean 'off' or 'off-line'when it fact it's the other way around. You can train dogs to do tricksbut I think I'm just too thick to learn this one! Thanks for the insight Garey. 73, Greg Roecker/n4osj Roswell, GA. -Original Message- From: Garey Barrell Sent: Friday, January 13, 2012 10:01 AM To: m coffey Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] L4 vs. L4B Mike - Couple of things. 1. The L-4 never was sold with 4-400s. I assume you mean 3-400Zs. 2. Electrically, yes, you can replace the 3-400s with 3-500Zs. The problem is that the '500s are a little taller and won't fit in some of the chimneys Drake supplied. There really isn't any reason to replace 'good' 3-400s with 3-500s as long as you stay within the original power specs. This is about the limit of the power supply anyway. Yes, you can get close to today's legal limit, if you really need that one quarter of an S-Unit increase. The main 'significant' difference between the two is that the B moved the ALC level control from the rear panel, and made it a 'push-pull' switch control to put the amplifier in standby. Pushing the knob IN takes the amplifier off line without turning it off. With the L-4, you have to switch the AC power off to bypass the amplifier. The 3-400/500Zs are 'instant on' tubes so not an operating problem, but you could argue about turning the amp on and off multiple times. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com m coffey wrote: Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4 vs. L4B
Hi Greg - You ever get that T-4X(?) running?? Those type of control switches were typically used to turn equipment on and off, pulling 'OUT' to turn the gear 'ON'. So Drake's implementation makes sense from that standpoint. That said, I too have trouble keeping it straight, even with it printed right there on the panel!! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Greg Roecker wrote: Of all the ham gear I've owned and operated, the position of the ALC switch on my L-4B for 'standby / operate' seems the most counter-intuitive function to me - and one I screw up more times than I care to admit. From just a human factors perspective, pushing the switch in would logically mean 'on' or 'in-line', and pulling it out would mean 'off' or 'off-line'when it fact it's the other way around. You can train dogs to do tricksbut I think I'm just too thick to learn this one! Thanks for the insight Garey. 73, Greg Roecker/n4osj Roswell, GA. -Original Message- From: Garey Barrell Sent: Friday, January 13, 2012 10:01 AM To: m coffey Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] L4 vs. L4B Mike - Couple of things. 1. The L-4 never was sold with 4-400s. I assume you mean 3-400Zs. 2. Electrically, yes, you can replace the 3-400s with 3-500Zs. The problem is that the '500s are a little taller and won't fit in some of the chimneys Drake supplied. There really isn't any reason to replace 'good' 3-400s with 3-500s as long as you stay within the original power specs. This is about the limit of the power supply anyway. Yes, you can get close to today's legal limit, if you really need that one quarter of an S-Unit increase. The main 'significant' difference between the two is that the B moved the ALC level control from the rear panel, and made it a 'push-pull' switch control to put the amplifier in standby. Pushing the knob IN takes the amplifier off line without turning it off. With the L-4, you have to switch the AC power off to bypass the amplifier. The 3-400/500Zs are 'instant on' tubes so not an operating problem, but you could argue about turning the amp on and off multiple times. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com m coffey wrote: Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4 vs. L4B
I consider it like a bench power tool switch. You pull ON and push OFF. This is done so you can punch the switch in the event of a disaster rather than having to carefully aim and grab. So to me, pulling to put the amp on line and pushing to put into standby makes sense. OTOH, I like big, easily visible toggle switches for operate and standby. If they have lights, so much the better! Ken WA2LBI On Fri, Jan 13, 2012 at 11:08, Garey Barrell k4...@mindspring.com wrote: Hi Greg - You ever get that T-4X(?) running?? Those type of control switches were typically used to turn equipment on and off, pulling 'OUT' to turn the gear 'ON'. So Drake's implementation makes sense from that standpoint. That said, I too have trouble keeping it straight, even with it printed right there on the panel!! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Greg Roecker wrote: Of all the ham gear I've owned and operated, the position of the ALC switch on my L-4B for 'standby / operate' seems the most counter-intuitive function to me - and one I screw up more times than I care to admit. From just a human factors perspective, pushing the switch in would logically mean 'on' or 'in-line', and pulling it out would mean 'off' or 'off-line'when it fact it's the other way around. You can train dogs to do tricksbut I think I'm just too thick to learn this one! Thanks for the insight Garey. 73, Greg Roecker/n4osj Roswell, GA. -Original Message- From: Garey Barrell Sent: Friday, January 13, 2012 10:01 AM To: m coffey Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] L4 vs. L4B Mike - Couple of things. 1. The L-4 never was sold with 4-400s. I assume you mean 3-400Zs. 2. Electrically, yes, you can replace the 3-400s with 3-500Zs. The problem is that the '500s are a little taller and won't fit in some of the chimneys Drake supplied. There really isn't any reason to replace 'good' 3-400s with 3-500s as long as you stay within the original power specs. This is about the limit of the power supply anyway. Yes, you can get close to today's legal limit, if you really need that one quarter of an S-Unit increase. The main 'significant' difference between the two is that the B moved the ALC level control from the rear panel, and made it a 'push-pull' switch control to put the amplifier in standby. Pushing the knob IN takes the amplifier off line without turning it off. With the L-4, you have to switch the AC power off to bypass the amplifier. The 3-400/500Zs are 'instant on' tubes so not an operating problem, but you could argue about turning the amp on and off multiple times. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com m coffey wrote: Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike __**_ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/**mailman/listinfo/drakelisthttp://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L4 vs. L4B
Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4 vs. L4B
The tubes are indeed different in several respects as are the amps. The L4 uses 3-400 tubes with chimneys that curve in at the top toward the heat dissipating plate cap. The L4B uses 3-500Z tubes with chimneys that are straight (same as a Coleman lantern globe). Whether the tubes are interchangeable depends on the physical size (one of those tubes is smaller than the other) and there is, I believe, a slight difference in some of the ratings on the tubes. The info is available online. The L4 does not have a standby switch on the front panel. The L4B has a standby switch on the front panel. Not sure about the L4, but the L4B has adjustable ALC pot on the front panel. L4 uses two 100K 50 watt resistors in parallel for part of the the bleeders and ALC circuit in the power supply. The L4B uses two 50K 50 watt resistors in series for part of the bleeder and ALC circuit in the power supply. Those are the main differences to my limited knowledge. 73, Evan, K9SQG -Original Message- From: m coffey r79b...@gmail.com To: drakelist drakelist@zerobeat.net Sent: Thu, Jan 12, 2012 5:17 pm Subject: [Drakelist] L4 vs. L4B Can anyone tell me the difference between the L4 and L4B ? Can one replace the 4-400s with 3-500s? Mike ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
