Tube change - WOW!

[RJLII]

I just swapped out the original Groove Tubes in my 2001 '65 DRRI with a new set of Tung-Sol 6V6GTs. What a difference! A warmer, rounder tone and very silky smooth breakup. They claimed "Creamy" versus "Crunchy" and they nailed it. It's a completely different amp. I need to get the bias setting dialed in before I crank it up much. I hope my meter shows up Monday!

[gopeteygo]

I just swapped out the original Groove Tubes in my 2001 '65 DRRI with a new set of Tung-Sol 6V6GTs. What a difference! A warmer, rounder tone and very silky smooth breakup. They claimed "Creamy" versus "Crunchy" and they nailed it. It's a completely different amp. I need to get the bias setting dialed in before I crank it up much. I hope my meter shows up Monday!

 

Changing tubes can really make a difference. When I get an amp I like to swap a few V1 tubes to see which gives the best tone. V1 swapping can make a big difference too.

[Steiner]

Save the old power tubes! When the meter arrives, plug 'em in and record the settings. Then crank the bias to the lower limit {play for a while} then to the upper limit and play. You'll be amazed at the faces your '01 '65 DR-RI has inside

[slider313]

The new Tung Sol 6V6GT is the best sounding 6V6's I've ever used. I have more than a few matched sets of NOS/NIB 6V6's like GE, Sylvania, RCA and Raytheon and I've A/B'd them all. The Tung Sol's are very close to grey plate RCA 6V6GTA but the RCA's don't have as much clean headroom. The Tung Sol's are just as warm as the RCA's and have a tighter bass and better note seperation.

[RJLII]

I got the bias dialed in on the new tubes today. I picked up a nice bias probe from Amp Head (here)

 

 

I was surprised when I checked the bias on the new tubes with the factory bias pot setting. Plate voltage was at 421 and the current was over 30mA. I'm glad I kept the volume really low prior to checking the bias. All the resources I checked suggested that was way too hot. I dialed it back to 22mA (about 60%) and everything still sounds great.

[tyguy]

I got the bias dialed in on the new tubes today. I picked up a nice bias probe from Amp Head (here)

 

 

I was surprised when I checked the bias on the new tubes with the factory bias pot setting. Plate voltage was at 421 and the current was over 30mA. I'm glad I kept the volume really low prior to checking the bias. All the resources I checked suggested that was way too hot. I dialed it back to 22mA (about 60%) and everything still sounds great.

you couldn't set current for 22ma on a real deluxe reverb(I have a real '65.When the current goes down the voltage goes up(@ 22ma way up).Hope you don't burn up your power tranny.Mine is always biased @ 35ma or so.The problem is finding tubes that can handle that much current.The reason Deluxe's sound so good is that there's a lot of current going thru the tubes.22ma will sound colder than a witche's tit unless you're playin' at Symphony Hall!The reissue Deluxe's may be different.I hope so in your case.

[slider313]

you couldn't set current for 22ma on a real deluxe reverb(I have a real '65.When the current goes down the voltage goes up(@ 22ma way up).Hope you don't burn up your power tranny.Mine is always biased @ 35ma or so.The problem is finding tubes that can handle that much current.The reason Deluxe's sound so good is that there's a lot of current going thru the tubes.22ma will sound colder than a witche's tit unless you're playin' at Symphony Hall!The reissue Deluxe's may be different.I hope so in your case.

 

35ma is very high for a 6V6 in a Deluxe Reverb. If you want to bring your plate voltage down use a 5V4 or 5R4 rectifier or a Weber Browner. Cooking your power tubes well above their maxium plate dissipation is not a good idea and running them that high will shorten their life considerably. My original '65 sounds great at 21ma per tube at 425v; which is 65% mpd. I use a 5V4 rectifier.

[RJLII]

35ma is very high for a 6V6 in a Deluxe Reverb.

 

I don't have a clue about the old versions, but I've done fairly exhaustive research on where to set my DRRI and plate voltages of 410 to 420 along with current ranging from 20 to 25 mA seems to be the norm. I was kind of shocked to find mine set to hot.

 

There seems to be some disagreement as to whether the Tung-Sol is really built as a 6V6 (12w) or a 6V6GT (14w) tube. It's marked 6V6GT but the amp discussion boards are lousy with conspiracy theorys. Running the math on dissipation at a plate voltage of 422 suggested setting the bias current at 20mA for 60% and 23.25mA for 70% with the assumption it was a 14 watt tube. 22mA Seemed like a happy medium for long tube life.

 

That said, the old Groove Tubes lasted 8 years biased to 30mA, and I have read reports from guys that run them jacked up that high as the norm. They generally claim great tone but acknowledge that they retube periodically. My setting of 422/22mA sounds really good on my amp with these tubes so I think I'll just let it ride. I'll revisit the issue in another 8 years (God willing and the creek don't rise).

[wingnut1]

I don't have a clue about the old versions, but I've done fairly exhaustive research on where to set my DRRI and plate voltages of 410 to 420 along with current ranging from 20 to 25 mA seems to be the norm. I was kind of shocked to find mine set to hot.

 

There seems to be some disagreement as to whether the Tung-Sol is really built as a 6V6 (12w) or a 6V6GT (14w) tube. It's marked 6V6GT but the amp discussion boards are lousy with conspiracy theorys. Running the math on dissipation at a plate voltage of 422 suggested setting the bias current at 20mA for 60% and 23.25mA for 70% with the assumption it was a 14 watt tube. 22mA Seemed like a happy medium for long tube life.

 

That said, the old Groove Tubes lasted 8 years biased to 30mA, and I have read reports from guys that run them jacked up that high as the norm. They generally claim great tone but acknowledge that they retube periodically. My setting of 422/22mA sounds really good on my amp with these tubes so I think I'll just let it ride. I'll revisit the issue in another 8 years (God willing and the creek don't rise).

 

Here is a link to some bias calculators that should help you get the proper idle current and plate voltage. Each set of tubes are going to be different and sometimes you will need to change the value of the resistor feeding bias pot in order to get the proper range. I generally like to set my amps at 70% of max plate dissipation, but sometimes if I want more clean headroom for a particular amp I'll bias it at 60-65%.

[RJLII]

Here is a link to some bias calculators that should help you get the proper idle current and plate voltage.

 

I didn't see the link, but I did find a few online calculators when I was doing my research.

 

http://www.webervst.com/tubes1/calcbias.htm

 

http://www.ax84.com/contrib/biascalc.php

 

 

Or the old school approach: Bias Current (mA) = Wattage/Plate Voltage where Wattage is expressed as the percentage of nominal tube wattage you wish to dissipate at idle. In my case 65% was the original target, so (14 Watts x .65)/422 = 21.6mA. Call it 22mA to keep things simple.

 

I formatted a little spreadsheet to do the math quick.