I had a chance today to run several brands of 12AV7's today in The 5E7 Bandmaster.
There is a big difference compared to having a 12AX7 in the V1 position.
Today I ran
Sylvania 12AV7, Small grey wrap around style plates.
This is a very warm tube, In a guitar amp environment it significantly reduced the dreaded single pickup growl in my junker Strat.
With my Good Strat it was amazingly quiet, and offered excellent overall tone.
When pushed they seemed to give a great 60's overdrive and though a bit raspy, it still had a very pleasant overall sound.
Next up
RCA glossy black wrap around plates.
Excellent tube with just a bit more shimmer than the Sylvania when running clean. When pushed hard these gave more of a Marshall type overdrive yet never became as raw or raspy
GE 5965 Grey Plates.
These look entirely different than the Sylvania and RCA counterparts.
The have conventional plate construction like the 12AX7 and easily as large internally.
Clearly the least noise of them all. Very complex tones and absolutely brilliant high end ring.
When pushed hard with these tubes, The overdriven tone was a bit more over the top than I like. Raw, Brash and a tad of fizz to my ears.
But, I need to retest in opposite order now, after running through several set lists and extreme volumes the ole ears can be very deceiving.
I have yet another style RCA to test.
I call these Mini Plate 12AV7's
They have a plate design that looks like a 12AX7 in shape, But Miniature.
I'll get pictures of these tubes posted asap. It appears there are several styles of construction and picking when one will of course be a personal taste thing.
I will however say I am very pleased with the ones I have tested so far and have experience no microphonic tendencies yet.
Trout
There is a big difference compared to having a 12AX7 in the V1 position.
Today I ran
Sylvania 12AV7, Small grey wrap around style plates.
This is a very warm tube, In a guitar amp environment it significantly reduced the dreaded single pickup growl in my junker Strat.
With my Good Strat it was amazingly quiet, and offered excellent overall tone.
When pushed they seemed to give a great 60's overdrive and though a bit raspy, it still had a very pleasant overall sound.
Next up
RCA glossy black wrap around plates.
Excellent tube with just a bit more shimmer than the Sylvania when running clean. When pushed hard these gave more of a Marshall type overdrive yet never became as raw or raspy
GE 5965 Grey Plates.
These look entirely different than the Sylvania and RCA counterparts.
The have conventional plate construction like the 12AX7 and easily as large internally.
Clearly the least noise of them all. Very complex tones and absolutely brilliant high end ring.
When pushed hard with these tubes, The overdriven tone was a bit more over the top than I like. Raw, Brash and a tad of fizz to my ears.
But, I need to retest in opposite order now, after running through several set lists and extreme volumes the ole ears can be very deceiving.
I have yet another style RCA to test.
I call these Mini Plate 12AV7's
They have a plate design that looks like a 12AX7 in shape, But Miniature.
I'll get pictures of these tubes posted asap. It appears there are several styles of construction and picking when one will of course be a personal taste thing.
I will however say I am very pleased with the ones I have tested so far and have experience no microphonic tendencies yet.
Trout
Yes, that's quite a bit of choice, you must have very discriminating ears, would be interested to see what you think is best in the final analysis.
For me this is the first time hearing the sound from one of these, and I'm trying to gain an ear for the subtleties. I did have a big 6L6 groove tube amp (possibly a Traynor) back about 10-15 years ago for a while, but left it behind when I moved to NC from upstate NY. We took those tube amps more for granted back then and me & my buddies just screwed around, without a critical ear.
The one 12AV7 that I did get just now with my last parts order is a GE NOS with the codes 59-04 188-5 (I don't know how to decipher the date codes). I'll give it a shot the next day or so and see what it sounds like.
For me this is the first time hearing the sound from one of these, and I'm trying to gain an ear for the subtleties. I did have a big 6L6 groove tube amp (possibly a Traynor) back about 10-15 years ago for a while, but left it behind when I moved to NC from upstate NY. We took those tube amps more for granted back then and me & my buddies just screwed around, without a critical ear.
The one 12AV7 that I did get just now with my last parts order is a GE NOS with the codes 59-04 188-5 (I don't know how to decipher the date codes). I'll give it a shot the next day or so and see what it sounds like.
One thing nice about my amp, and most likely yours also is the addition of the master volume.
I am finding that I can get amazing clean tones running the master at around 8 and keeping the bright channel around 2-4.
This has a huge fat bottomed sound with amazing chime to the highs.
Reverse those settings, Bright channel on 8 and master on 3 really screams 60-70's rock. Much darker and gritty.
I can not see how they could have ever done without the master volume.
I just ran through the entire group I tested above and in all honesty, I can not decide which one I like the best.
I am going to now try them in my 5E3 deluxe combo and see how they do in a higher vibration enviroment. Nothing can torture a preamp tube worse than a smaller 1-12 combo amp with the tubes hanging behind the speakers
The 5E3 was actually my intended home for these tubes, But I had a 5E7 bandmaster chassis on the bench and figured what the hay.
I'll keep you posted
Trout
I am finding that I can get amazing clean tones running the master at around 8 and keeping the bright channel around 2-4.
This has a huge fat bottomed sound with amazing chime to the highs.
Reverse those settings, Bright channel on 8 and master on 3 really screams 60-70's rock. Much darker and gritty.
I can not see how they could have ever done without the master volume.
I just ran through the entire group I tested above and in all honesty, I can not decide which one I like the best.
I am going to now try them in my 5E3 deluxe combo and see how they do in a higher vibration enviroment. Nothing can torture a preamp tube worse than a smaller 1-12 combo amp with the tubes hanging behind the speakers
The 5E3 was actually my intended home for these tubes, But I had a 5E7 bandmaster chassis on the bench and figured what the hay.
I'll keep you posted
Trout
Well, I finally finished the cabinet as well, won't win any awards for it, but it came out to be a nice package. My wife just got back from a 2 week business trip, and I'll crank it up for her tomorrow. Had to leave it in the laundry room, as she has asthma & the fumes are still coming off of it from the lacquer.
Used birch plywood, joined by dowels, separate grille plate with heavier cloth. The main box is covered with actual tweed fabric, not tolex, and several coats of old-fashioned lacquer.
Brass corner plates, Ernie Ball handle and padded feet.
So it was a good 35 hour project, all told, and cost me a good $550.
Used birch plywood, joined by dowels, separate grille plate with heavier cloth. The main box is covered with actual tweed fabric, not tolex, and several coats of old-fashioned lacquer.
Brass corner plates, Ernie Ball handle and padded feet.
So it was a good 35 hour project, all told, and cost me a good $550.
Trout said:
Sorry to dig up such an old thread. I've been curious about twin triodes with ~40 mu, and have been searching up stuff on these guys.
While the 'AY7 and the 'AV7 both have a mu around 40, the plate resistance of the two is drastically dissimilar. For a given plate and grid voltage, you'll get a lot more (plate) current out of a 'AV7.
I'm hoping to learn something myself about the significance of plate resistance, and how it affects a tube's ability to function in a driver stage.
Re: Re: 12AV7- 5965 Vs 12AY7
It isn't so much a question of plate resistance, but of transconductance. While it's true that the 12AV7 and 12AY7 have a u= ~40, the types achieve it differently
12AV7:
r(p)= 4K8
g(m)= 8.5mA/V
12AY7:
r(p)= 25K
g(m)= 1.75mA/V
The lower plate resistance and higher g(m) of the 12AV7 allows it to operate at higher Q-Point currents to source more current into a load, such as the Ci of a subquent stage. This improves high frequency performance. Given the lower plate resistance, the 12AV7 will have better high frequency performance, important as this is an RF type. (Just about the worst linearity of any type I've seen so far, so no good for HiFi, but apparantly OK for MI amps. Otherwise, use 'em for RF amps, frequency multipliers, mixers where linearity isn't such a big concern.)
The 12AY7, operating at much smaller Q-Point currents, can make use of big Rp's without needing excessive voltages so that you can get high voltage gains. Given the low plate currents, it needs to operate into a Hi-Z, low C, load. So you'd most likely see 12AY7s "up front" and 12AV7s driving the finals.
Ty_Bower said:
It isn't so much a question of plate resistance, but of transconductance. While it's true that the 12AV7 and 12AY7 have a u= ~40, the types achieve it differently
12AV7:
r(p)= 4K8
g(m)= 8.5mA/V
12AY7:
r(p)= 25K
g(m)= 1.75mA/V
The lower plate resistance and higher g(m) of the 12AV7 allows it to operate at higher Q-Point currents to source more current into a load, such as the Ci of a subquent stage. This improves high frequency performance. Given the lower plate resistance, the 12AV7 will have better high frequency performance, important as this is an RF type. (Just about the worst linearity of any type I've seen so far, so no good for HiFi, but apparantly OK for MI amps. Otherwise, use 'em for RF amps, frequency multipliers, mixers where linearity isn't such a big concern.)
The 12AY7, operating at much smaller Q-Point currents, can make use of big Rp's without needing excessive voltages so that you can get high voltage gains. Given the low plate currents, it needs to operate into a Hi-Z, low C, load. So you'd most likely see 12AY7s "up front" and 12AV7s driving the finals.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.