Anyone have any experience with the 6GT5 pentode as an audio tube? Is it suitable for hi fidelity application ? What about musical instrument amplification ?
Grommes / Precision / Frazier used these in their higher-power amps. They've gotten harder to find and somewhat expensive. 6DQ6 / 6GW6 are listed as having similar curves and can be found for peanuts (A plus: they use octal sockets. A minus: they have plate caps).
Thanks Tom,
I thoght the 6GT5 was only for horizontal deflection applications, but I found an am made by Rich(?) licensed by W.E. that uses 4 6GT5, has huge iron and a super clean dress as well. I'll put it on a shelf with the 6 or 8 others....
BTW...Antique Electronics has the 6GT5A for $13.00...although the amp I have has 4 already. :darkside
I thoght the 6GT5 was only for horizontal deflection applications, but I found an am made by Rich(?) licensed by W.E. that uses 4 6GT5, has huge iron and a super clean dress as well. I'll put it on a shelf with the 6 or 8 others....
BTW...Antique Electronics has the 6GT5A for $13.00...although the amp I have has 4 already. :darkside
The amp manufacture "Standel" used this valve back in the early/mid Sixties in their amps. The amps had an FET front end and a 12AX7 as the phase inverter and the 6GT5A as the output valve! These amps were really clean, but sounded great/big! Alot like a Vox 7120 or a Magnavox era Ampeg.
The experience of using 12GT5 (which is equal to 6GT5 except for voltage and heating current) in a guitar amp may help.
12GT5-guitar amp.
12GT5-guitar amp.
All same tube except for base and possible plate cap:
12/6GT5 12/6JT6 (no cap)
12/6GJ5 12/6JB6
12/6GW6 (octal)
Similar tubes: 12/6DQ6 12/6JN6 12/6GE5 6JM6 6GV5 6FW5
12/6GT5 12/6JT6 (no cap)
12/6GJ5 12/6JB6
12/6GW6 (octal)
Similar tubes: 12/6DQ6 12/6JN6 12/6GE5 6JM6 6GV5 6FW5
single ended 12gt5 with 6bn11 all pentode amp with no global feedback, sounds very nice indeed....
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Tony Tecson,
Looks great!
I love those Philippine Woods.
When I left the Philippines, my belongings were shipped in a very large Mahogany Crate.
Did you wire the output tubes in Beam Power mode, UL mode, or Triode mode?
Looks great!
I love those Philippine Woods.
When I left the Philippines, my belongings were shipped in a very large Mahogany Crate.
Did you wire the output tubes in Beam Power mode, UL mode, or Triode mode?
pentode mode all the way including the 6bn11 voltage amplifiers, the 12gt5's are run pentode mode, (not really a fan of UL) o'schade plate to grid feedback,
all G2's are fed off 140vdc from a Salas type regulator, enhancement mosfet CCS, and zener shunts....
though provisions for global negative feedback was there, i did not connect those, what i heard coming out of the speakers convinced me that gnfb was not needed....
the bamboo wooden casings provided a suitable housing for this project...
all G2's are fed off 140vdc from a Salas type regulator, enhancement mosfet CCS, and zener shunts....
though provisions for global negative feedback was there, i did not connect those, what i heard coming out of the speakers convinced me that gnfb was not needed....
the bamboo wooden casings provided a suitable housing for this project...
The low 220 volt maximum spec for G2 pretty much limits you to pentode mode except for low plate voltages. Most every tube intended tor TV sweep duty works quite well for audio amp service, when operated within their ratings.
The 6GT5 is a horizontal sweep (line output) tube. These usually have rather low G2 voltage specs. These specs need to be respected, especially on the later vintage tubes.
The 6GT5 and it's relatives will make 75 to 100 watts of audio per pair run as pentodes with 150 volts on G2 and about 500 volts on the plate into a 3300 ohm OPT.
The 6GT5 is a horizontal sweep (line output) tube. These usually have rather low G2 voltage specs. These specs need to be respected, especially on the later vintage tubes.
The 6GT5 and it's relatives will make 75 to 100 watts of audio per pair run as pentodes with 150 volts on G2 and about 500 volts on the plate into a 3300 ohm OPT.
i purchased a lot of tv power tubes when they were selling for U$1 a pop, enough to last me a lifetime......tv tubes are a lot of fun.....
True. The older tubes that were derived from the 6DQ6 like the 6GT5 can work in triode or UL at plate voltages up to maybe 350 volts. They are capable of operation at much higher voltages in pentode mode though. The 6GT5A is rated for a DC plate supply voltage of 770 volts with a peak voltage rating of 6500 volts. G2 is 220 volts max.
The newer tubes with even higher perveance will eventually runaway at 350 volts or lower. I had 4 different 6LW6 tubes go into runaway in triode mode. Two at 400 volts, and two at 330 volts. I have seen a pair in P-P put out 300 watts on 630 volts into 2500 ohms. See post #25 in this thread:
If UNSET and the RCA50W Had a Baby
The smallest offspring of the 6DQ6 is the 6GF5. It's a 6GE5 with its plate wings cut off tightly stuffed into a small bottle. They make 75 watts per channel in the amp shown in post#2 in the same thread. The 6GT5 is the same tube with a larger plate and will make 100 watts per pair under the right conditions.