About Ampegs

[vg3000]

and what about 7027s?do you think they sound closer to 6l6s?

7027's are over built 6L6's but sound basically the same. I've seen graphs with nothing showing any difference. I can tell the difference. Comparing NOS RCA's (they were made for Ampeg by) of each type, I like 7027's over 6l6's in this circuit.
Both my VT-40's have the original 7027's happily chugging along after close to 40 years now.
I've heard a lot of crap about new production 7027's and I think I would pass on them if I ever should need to replace mine.

[scole]

ampeg v4

in case anyone is interested, i still have a mathing fork lift that came with my v4.

[whammy64]

Has anyone tried the new Ampeg J-20?

Just curious about the Ampeg J-20 Jet 20W 1x12 combo? It's billed as a hand-wired, tube-rectified, 5E3-type with a alnico speaker.

Looks cool. But would I be better building a 5E3 kit for about the same money? Tweed looks even cooler to me but tone is the goal here. I'm a blues, soul picker playing small clubs and I've never used anything but Fender amps. But some Ampegs I've played in recent years sounded real good in the store.

I'm more interested in playing than building but the kits look really appealing to me.

[Diablo]

I have a 1972 V4 that I bought new. It is a very versatile amp. If you want more powertube distortion at lower volume, remove two of the output tubes and set the impedance switch to half the rated value of your speaker cabinet(s). For an 8 ohm cabinet, set the switch to 4 ohms. I really like the sound of my amp set this way.

[Robert M. Martinelli]

too much focused on tube types

Hi ironfly,
I think, as someone has already pointed out, that you' re too much focused on the tubes' type: you could design different sounding final stages using the same tube type, the possibilities and variables are almost infinite......

The way each tube type sounds has to do with its phisical characteristics, but it must be said that a lot of tubes are virtually the same tube with a different name... if you look at old datasheets, you 'll see 6L6s and 7027s have identical curves, and I mean identical.....

Let me tell you a story....
Time ago I had to repair an old ( 1966 ) Ampeg B18-X a friend of mine was using for both live and studio performances, and, due to the poor 7027s availability and their higher price ( I don 't know about prices and availability in the US, but here in Italy 7027s cost twice and half a 6CA7 and they' re hard to find ) I modified the amp ( in a fully reversible manner ) to use 6CA7s and he is very happy with the result, has just recorded a studio CD and promised me to bring a copy to let me hear the sound...

Hope this helps

Bob

[tubby]

i got an ampeg vt-22 sitting on my work bench right now and i'll tell you this:
this is the heaviest combo i've ever seen. if you're not arnie you'll need two people hauling this thing.

soundwise it's pretty much two words: LOUD and clean. i fitted a mv on this one and it's still impossible to get a decent crunch sound. the distortion on channel one sounds totally crap. no surprise, it's a diode clipping circuit. back then that was (solid) state of the art.

other than that it's built like a tank and makes a superb bass amp imho. very effective tone circuit btw.

[Rick Erickson]

back then that was (solid) state of the art.

No, even back then it pretty much sucked. Unfortunately, the whole distortion preamp thing wasn't very refined yet, and there weren't the number of combo players/technicians as we see these days. Todays designers seem to have a better handle on the good vs. bad distortion dilemma.

[Diablo]

I'm always amused by the new fascination with old Ampeg guitar amps, because I remember guitar players generally not liking them back in the 70's because they were too clean sounding.

Some guitarists liked 'em, some didn't. Here's someone that did - it's a VT-40, half the VT-22. Guitarist is Jeff Beck.

http://www.youtube.com/watch?v=-p05vOgGNSo

[Rob Mercure]

Well folks,

To steer this thread slightly back to one other discussion points: At least in older production tubes - I'm not versed enough concerning the current former Soviet Bloc issue - the EL34 and the 6CA7 really were very different sounding tubes with very different physcial construction. The best way to describe the relationship is "equivalent" but not identical. When the EL34 was new and under patent US manufacturers didn't want to license production from Mullard/Phillips so "our" 6CA7 resulted and, as best I know, this pentode (I use this term as distinct from a beam power tube) was cobbled together from beam power tube parts that were already on the production line. Over the years I've saved tubes that were totally dead or shorted or accidentally broken (sob!) so I've got a lotsa examples to examine including 6CA7 from both RCA and Sylvania (If I remember correctly, haven't looked in a while) as well as broken Type II Mullard EL34s which should serve to establish a "type" for each issue. The EL34 has smaller, slimmer, thinner plates assembly with a much more open and thin screen grid and a much close wound suppressor grid while all the elements are spaced much closer exept the cathode to grid spacing which seems to be more or less identical (sorry, but the it's hard to measure without destroying the sample).
The 6CA7 is quite the opposite with a very robust plate that was either borrowed from a 6L6 type or 6550 (seems a bit small for a 6550 though but there are other tubes like a 6AV5 or 6AU5 that are close) and a hefty screen grid with thicker wires and a "wispy" supressor grid. Again spacing is more open with the exception of the cathode to control grid spacing.
The EL34 is often described as having a "soft" vacuum which I suppose means less vacuum - while I suspect that the 6CA7 was pumped down like the other tubes on the US/Canadian assembly lines. Having never done a "TTD" (test 'til destruction) on the two varieties of tube (like I'm gonna burn up the other Mullard EL34s I've got - yeah, right!) I have no empirical evidence that the 6CA7 is a more robust design but my "instinct" suggest it is and I really don't think that classic EL34s would survive in a Music Man 130 watt chassis if toured with.
Just my "no so" humble opinion. And, again, this should not be taken to presume that the current production 6CA7s are so constructed - I don't have a dead example to relate to but if someone had a dead one that they want to supply please send me a private message. As far as the EL34s go if anything they seem to be less robust than the Mullards which kinda both supports and confounds my assertions.

Rob

[cminor9]

I've been told these beasts rely more on the preamp section when pushed to overdrive beacuase of their power amp's loudness...it looks a bit like the way overdrive occurs in Mesa-boogies or Tweed Fenders (compared to Blackface/Silverface Fenders).

Tweed Fenders are *all about* power tube saturation (and of course, the preamp saturation is there too). I know it's not directly pertinent to the conversation, but still...

The only Ampeg I have ever played and liked was a reverborocket, FWIW.

[Dave Curtis, dB AudioTech]

Well folks,

To steer this thread slightly back to one other discussion points: At least in older production tubes - I'm not versed enough concerning the current former Soviet Bloc issue - the EL34 and the 6CA7 really were very different sounding tubes with very different physcial construction. The best way to describe the relationship is "equivalent" but not identical. When the EL34 was new and under patent US manufacturers didn't want to license production from Mullard/Phillips so "our" 6CA7 resulted and, as best I know, this pentode (I use this term as distinct from a beam power tube) was cobbled together from beam power tube parts that were already on the production line. Over the years I've saved tubes that were totally dead or shorted or accidentally broken (sob!) so I've got a lotsa examples to examine including 6CA7 from both RCA and Sylvania (If I remember correctly, haven't looked in a while) as well as broken Type II Mullard EL34s which should serve to establish a "type" for each issue. The EL34 has smaller, slimmer, thinner plates assembly with a much more open and thin screen grid and a much close wound suppressor grid while all the elements are spaced much closer exept the cathode to grid spacing which seems to be more or less identical (sorry, but the it's hard to measure without destroying the sample).
The 6CA7 is quite the opposite with a very robust plate that was either borrowed from a 6L6 type or 6550 (seems a bit small for a 6550 though but there are other tubes like a 6AV5 or 6AU5 that are close) and a hefty screen grid with thicker wires and a "wispy" supressor grid. Again spacing is more open with the exception of the cathode to control grid spacing.
The EL34 is often described as having a "soft" vacuum which I suppose means less vacuum - while I suspect that the 6CA7 was pumped down like the other tubes on the US/Canadian assembly lines. Having never done a "TTD" (test 'til destruction) on the two varieties of tube (like I'm gonna burn up the other Mullard EL34s I've got - yeah, right!) I have no empirical evidence that the 6CA7 is a more robust design but my "instinct" suggest it is and I really don't think that classic EL34s would survive in a Music Man 130 watt chassis if toured with.
Just my "no so" humble opinion. And, again, this should not be taken to presume that the current production 6CA7s are so constructed - I don't have a dead example to relate to but if someone had a dead one that they want to supply please send me a private message. As far as the EL34s go if anything they seem to be less robust than the Mullards which kinda both supports and confounds my assertions.

Rob

I'll add that the only tubes that sounded right or lasted long in my MM 212-65 were the Sylvania 6CA7s that came stock, AFAIK. They lasted for nearly 25 years until an unexpected fall [1] cracked a solder joint that cooked one of them.

Also, the 7027A is the same as a good 6L6GC; it just has more of the tube elements brought out to external pins. If your amp doesn't use these you're good to go. All the Ampegs I know of didn't, so you're good to go.

[1] ArmorAll + Tolex = Slip & Fall to cement floor, missing foot by an inch. ArmorAll=Bad4Amp$

[WholeToneMusic]

KT77

Does the new (and old) JJ KT 77 belong to the el34/6ca7 family,too?
Which of these three tubes gets closer to the 6L6/6550 grinding,uncompressed break up?

The KT 77 falls into the EL34 category. The JJ KT77 is has simialar tonal characteristics to the JJ EL34L. The JJ KT 77 has more low end response and is smoother sounding than the JJ EL34L. The KT 77 is a Kinkless Tetrode design. You will get more of an extended 6L6 bottom end with the JJ KT 77 because of it's extended low end response, however I don't think the JJ KT 77 is quiet as round as the 6L6. IMO