Quick question about my EVH. With the 50watt 5150 III having one less preamp tube than its bigger brother, is the V4 preamp tube still first in line on the lead channel (other than V1)? There's the chart for the 100 watt.
EVH tube position question
- Thread starter Tercero
- Start date
GuitarHack
Krank it UP!
Howard (the guy who designed the 50W) posted this on TheGearPage:
Here is the tube run down -
V1 - 1/2 for CH1/2; 1/2 for CH3
V2,V3, V4 - CH3
V5, V6 - CH1/CH2
V7,V8,V9 - Power Amp
So Half of V1, then V2 is the next in line for Channel 3 (Red Channel).
Here is the tube run down -
V1 - 1/2 for CH1/2; 1/2 for CH3
V2,V3, V4 - CH3
V5, V6 - CH1/CH2
V7,V8,V9 - Power Amp
So Half of V1, then V2 is the next in line for Channel 3 (Red Channel).
GuitarHack
Krank it UP!
Here is some other interesting (well I thought so 
) stuff he posted about the differences between the 50 and 100W:
Originally Posted by hkaplan131
I have run the 100W and the 50W side by side many times. First, expecting 50W head to have as much punch and headroom as a 100W head is just plain wishful thinking. It is like asking a 50W bulb to be as bright as a 100W bulb.
With that said I can tell you that the 50W head does have plenty of punch. The power supply in the amp is a big factor, and I made the 50W supply pretty stiff within the size constraints I had to work under. Also the addition of the Resonance Control (100W has fixed Resonance) allows one to boost the low end a bit get some more out of the amp.
Another option if you get the head is to go out and get a set of the #9 Gain 6L6's in a matched Quad from Fender. (Matched duets are in the works.) Use a pair and take the head to a qualified servicece center and have the bias set at 60 mA for the pair of tubes. This will give the maximum punch for this amp. The amp ships with matched duets, but all gain numbers are used. The factory we use does not have the capability to test the gain of the tubes they buy from JJ. Selection of tubes is an expensive procedure and obviously results in a fallout of tubes if you want to use the highest gain tubes in a particular amp. At Fender the 100W head uses the highest 3 gain range tubes.
Also, someone posted that the transformers in the 50W head are as big as the 100W head. This is not true. Both the Power and the Output transformers are smaller, but of course designed to meet the specifications of the head. And they are Schumacher designed and built transformers, the company we have been using for decades.
) stuff he posted about the differences between the 50 and 100W:Originally Posted by hkaplan131
I have run the 100W and the 50W side by side many times. First, expecting 50W head to have as much punch and headroom as a 100W head is just plain wishful thinking. It is like asking a 50W bulb to be as bright as a 100W bulb.
With that said I can tell you that the 50W head does have plenty of punch. The power supply in the amp is a big factor, and I made the 50W supply pretty stiff within the size constraints I had to work under. Also the addition of the Resonance Control (100W has fixed Resonance) allows one to boost the low end a bit get some more out of the amp.
Another option if you get the head is to go out and get a set of the #9 Gain 6L6's in a matched Quad from Fender. (Matched duets are in the works.) Use a pair and take the head to a qualified servicece center and have the bias set at 60 mA for the pair of tubes. This will give the maximum punch for this amp. The amp ships with matched duets, but all gain numbers are used. The factory we use does not have the capability to test the gain of the tubes they buy from JJ. Selection of tubes is an expensive procedure and obviously results in a fallout of tubes if you want to use the highest gain tubes in a particular amp. At Fender the 100W head uses the highest 3 gain range tubes.
Also, someone posted that the transformers in the 50W head are as big as the 100W head. This is not true. Both the Power and the Output transformers are smaller, but of course designed to meet the specifications of the head. And they are Schumacher designed and built transformers, the company we have been using for decades.
MarcusGHedwig
Member
TheWinterSnow
Den Mørke Natt
The 120W peavey's, yes. The Fender 100W and 50W are different stories. At 60mA it would seem like they lowered the plate voltage in the power section.
GuitarHack
Krank it UP!
Correct.
No lowered plate voltage.
Originally Posted by hkaplan131
.......The bias is set by measuring the voltage across R157, set at 60 mV which translates to 60 mA (30 mA per tube). Note that this should only be done by a qualified technician. There are dangerous high voltages inside the amp!!
From Here:
http://www.thegearpage.net/board/showthread.php?t=835662&page=55
TheWinterSnow
Den Mørke Natt
Makes now but why the hell would you use a single resistor for the total current? It is absolutely useless as you cannot use it to rebias without needing a probe, which again, makes that test point, well useless.
