25 Watt Plexi with EL-34's???

[M Fowler]

I'm surprized colossal hasn't chimed in he has a youtube video of the 6v6 plexi he built which is a darn nice amp.

Mark

[Colossal]

I'm surprized colossal hasn't chimed in he has a youtube video of the 6v6 plexi he built which is a darn nice amp.

Mark

A 6V6 Plexi is a great amp and highly recommended. I used a PT with 325-0-325 based on how Mark Huss originally built his (about 440VDC on the plates!) but it would be better with 290 to 300V for the secondaries (Mark's recommendation too). OT can be 6k6 to 8k for superb results. I used a 20W Marshall OT at 7k8. If you run your 6V6s at really high voltages, it's best to reduce the screen voltages some. A 5k 5W resistor in series with a choke works well for this. JJs sound very good and hold up exceeding well to high voltage punishment.

At high voltages (440-460V) 6V6s have a bit of a hard bark. This may be desirable to some. Lowering the plate voltage will soften their tone up a bit more. I used a power supply with 47uF -> 5k/10H choke -> 47uF -> 22uF -> 22uF -> 22uF and it had wonderful compression with just the right amount of Marshall sponge. Raising the reservoir cap to 47uF || 47uF (96uF) made it too hard an glassy sounding and it lost its three dimensional sound, so I went back to 47uF; much better. To build another one, I would probably go for lower voltages, and even softer filtering such as 32uF for plates, 16uF screens, 32uF PI and preamp to be closer in sound and feel to the old Superleads.

My amp put out a very loud 22+ watts and while it would probably not hang with the brute force of a 50W JMP 1987 or 100W 1959 Superlead it was a freakishly loud amp! Fantastic tone too.

[Weathered]

I can't contribute to the 6V6 Plexi discussion, but I have a Trinity Triwatt that I built last year that is a Hiwatt voiced preamp tied to a 6V6 power section running at higher voltage (440V on the plates if memory serves correctly), and it is LOUD. Plenty loud for gigging with a rock band, and I think it's about perfect volume-wise to get into the sweet spot of the power section without killing the sound guy with guitar.

I really think that the 6V6 is a useful tube for modern gigging.....just my $.02.

[tubeswell]

I really think that the 6V6 is a useful tube for modern gigging.....just my $.02.

Yup, 6V6 PP amps definitely make great gigging amps for those who know how to use them in a properly mic'd situation. The JJ6V6S is particularly rugged and a pair or them sound particularly nice at about 430V 27mA into 5 or 6k being pushed by an LTP inverter, with one or two gain stages in front of that and a treble booster or hotcake in front of that.

6L6s and EL34s are great louder but when you try to get them to distortion levels in club type gigs, you need earplugs. Whereas the 6V6 goes into sag and bloom and sustained feedback territory at reasonable volumes which is perfect for rock etc.

[rdamato]

I really think that the 6V6 is a useful tube for modern gigging.....just my $.02.

Yup, 6V6 PP amps definitely make great gigging amps for those who know how to use them in a properly mic'd situation. The JJ6V6S is particularly rugged and a pair or them sound particularly nice at about 430V 27mA into 5 or 6k being pushed by an LTP inverter, with one or two gain stages in front of that and a treble booster or hotcake in front of that.

6L6s and EL34s are great louder but when you try to get them to distortion levels in club type gigs, you need earplugs. Whereas the 6V6 goes into sag and bloom and sustained feedback territory at reasonable volumes which is perfect for rock etc.

My thoughts exactly!!

[Colossal]

Yup, 6V6 PP amps definitely make great gigging amps for those who know how to use them in a properly mic'd situation. The JJ6V6S is particularly rugged and a pair or them sound particularly nice at about 430V 27mA into 5 or 6k being pushed by an LTP inverter, with one or two gain stages in front of that and a treble booster or hotcake in front of that.

This is my experience exactly. 2x6V6 JJs running at 440V and biased warmly sound fantastic and they tolerate the abuse with no issue. I had a pair with three years on them. They quit sounding good but never failed.

[CHIP]

My 6V6 Plexi is also a loud 22 watts.
Mine is a little different from Marks original. I built mine with a tube rect. (5AR4). Voltages on my plates are 365V. Filtering is 40mF >- 1k (no choke) 40mF >-30mf>-47mf>-47mf.
I was going to raise the 2 40mf's to 47mf.
but after reading Colossals post I may reconsider and leave them as is.
I may also go with a choke, and raise the 1k to 5k.
What I like is I can switch between a Strat or Les paul during gigs and both sound great. Strat is nice and full sounding .I put a Zen Drive in front and set it so it adds just a little gain and when I punch it in I get this wonderful smooth overdrive, which is just a tad different from the overdrive of the amp without the pedal.

[rp]

I was having a discussion with an amp builder expressing my desire for a ~25 Watt, 6V6 Plexi style amp.

maybe this:

http://www.classictubeamps.com/6v6plexi.html

there are detailed build explanations and a schematic posted on the site so I won't copy and attach it here.

Not sure where I found this site, maybe the builder posts here?

Trinity Amps I think offers a 6V6 Marshall (or Hiwatt?) too.

[Colossal]

http://www.classictubeamps.com/6v6plexi.html

Not sure where I found this site, maybe the builder posts here?

Yep, that's Ryan's site. He goes by KT66 around these parts.

[Weathered]

Trinity Amps I think offers a 6V6 Marshall (or Hiwatt?) too.

I have one of his 6V6 based Hiwatts - it is a fantastic amp. Awfully damn close to a wound-up DR103 without the volume. Love that amp a ton. Sadly, selling it to fund my first semester of grad school.

[Zippy]

Trinity Amps I think offers a 6V6 Marshall (or Hiwatt?) too.

I have one of his 6V6 based Hiwatts - it is a fantastic amp. Awfully damn close to a wound-up DR103 without the volume. Love that amp a ton. Sadly, selling it to fund my first semester of grad school.

Better not to have the distractions during grad school. Do well and you might be able to buy several when you are done. I bought a pretty nice guitar for my graduation present.

G'luck with your studies!

What, by the way, is your area of interest?

[Weathered]

Trinity Amps I think offers a 6V6 Marshall (or Hiwatt?) too.

I have one of his 6V6 based Hiwatts - it is a fantastic amp. Awfully damn close to a wound-up DR103 without the volume. Love that amp a ton. Sadly, selling it to fund my first semester of grad school.

Better not to have the distractions during grad school. Do well and you might be able to buy several when you are done. I bought a pretty nice guitar for my graduation present.

G'luck with your studies!

What, by the way, is your area of interest?

Actually going back to pursue my MBA with a focus in Finance. I'm going to keep building amps on the side, but sadly, my talents are in business and not electrical engineering.

[dju]

I'm curious, it seems like more people are building low power plexis with 6V6 power tubes and not el84's. is there a reason why or just preference? I'm thinking that el84's would sound closer to el34's. I'm in the process of gathering parts to try and build a 1987 circuit with el84's but ya'll now have me wondering if there is something better about 6V6's.

thanks for ya'll's input,
dj

[KT66]

1 difference I can think of in making the circuit with el84s compared to 6V6s is that typical plate voltages on 84s in guitar amps are in the low 300s, which is going to make the voltages in the preamp be around 40% lower than a standard plexi type amp, which I am not saying is bad, just different. There are a lot of EL84 amps that are popular in the DIY world, I bet someone here will recommend a plexi type variant that is proven, like maybe an 18W TMB ? The 2 hole Rocket that a number of us have built is very similar to the Plexi/bassman circuit ( the preamp is like a VOX AC30 TB channel) so I don't see why you couldn't make a cool plexi with 84s.

[rp]

...but ya'll now have me wondering if there is something better about 6V6's

I never built or heard a 6v6 Marshall but I've never heard an EL84 amp that really sounded like a EL34 Marshall. On the other hand a Tweed Deluxe, especially with a greenback, comes darn close to a mini Marshall. And, the JTM45 started out a 6L6/5881 amp. Anyway, that's my take on it.

edit: good point about the preamp voltages!