TALK @ PhilMusic.com - The Online Home of the Pinoy Musician
The Musician Forums => Guitar Central => Topic started by: lolwat on August 07, 2014, 02:12:49 AM
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I think it's safe to say that over here, we all agree that tube amplifiers simply sound better than other alternatives most of the time. That said, one of the greatest hassles of owning a tube amp is keeping track of preamp and power amp vacuum tubes' life cycle of sorts. For example, my own tube amp back at home has a terrific drive channel when boosted with a tubescreamer-type pedal, but tends to start feeding back uncontrollably due to one or two preamp tubes going microphonic. This by the way is an amp which has only been taken to live performances 3 or 4 times, and therefore has not seen much action (something I'd like to change in the future).
Issues similar to the above are linked to the fact that tube amplifiers, especially mid- to high-powered units, often use anywhere from 5 to 10 vacuum tubes, sometimes even more. While amps which require a considerable number of vacuum tubes to work properly use all of them for various applications, e.g. preamp gain stages for overdrive/distortion, rectification, effects loop/reverb driver, etc., what usually happens in local bars is that guitarists bring their own distortion pedals, plugging their effects into the clean channel of the provided amplifier/s (the clean channel of most modern tube amplifiers usually utilize fewer tubes than when the same amp is used on the drive channel). In light of this, I think it's practical for pedal users (and bar owners to some extent) who insist on playing through tube amps to select one with a nice single clean channel and enough wattage to play with a band, yet still use a minimum of tubes for ease of maintenance.
I won't pretend to be a gigging veteran, but the vast majority of venues I've seen watching my friends play usually have amps that are 50 watt solid-state combos. On thegearpage.net, most gigging musicians favor tube combos that are 15-20 watts in power, as they enjoy the sound of the amps' natural overdrive. Based on this, I'd say a good wattage rating for a gigging amp to have adequate volume and headroom would be in between 20 and 50 watts.
With the things I wrote above, I think it might be a good topic to talk about tube amplifiers within the aforementioned parameters which sound good but, again, require fewer tubes (AFAIK amps which only need at most 2 vacuum tubes exist). This almost automatically means that high-gain tube amps are excluded, so maybe our fellow forumites with lots of gear experience can mention amps which are predominantly clean, and are good pedal platforms to boot.
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What you are suggesting is OK and all BUT tube preamp and power amp circuity is designed based on the sound a musician is after for.
For example, the JCM800 would have fewer preamp tubes (3 I think) and would only produce an overdriven/crunch tone. You'd need an OD pedal to boost the signal and overdrive the preamp to get metal tones.
Compare the JCM 800 to the Peavey 5150, with the Peavey you can easily dial-in heavy gain tones without an aid of an overdrive pedal (more preamp tubes).
The number of tubes in the power section allows the amp to be louder while maintaining clean headroom. For example, a twin reverb will always over power a reverb deluxe.
I used to have a Peavey Windsor Studio. You can easily swap the one power amp tube to an EL34, 6L6 or KT77. Rated at 15-20 watts, it is not loud enough to use with a drummer (unless mic'ed to a PA).
The Epiphone Valve Jr has a lone EL38, rated at 8 watts but again will not be loud enough without a PA system.
From experience, it is necessary to know your amp and adjust accordingly to the venue and other gear you are using. I always bring my own equipment to gigs and the chances for me to have bad tone is lower than using the amp provided in the venue.
Just to add:
Tube feedback can be caused by a broken (or loose) preamp tube or the actual preamp tube configuration.
Cascading multiple 12ax7c will give you high gain at the same time is more prone to feedback. You can reduce the gain of an amp (and feedback) by replacing the 12ax7c with an 12ax7b or 12ax7a or 12at7 (much less gain). It will also drastically change the sound of your amp.
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Good points sir.
I actually have a longstanding dream to DIY a circuit mating a 1-preamp tube front end to a 1-power tube output section, which I believe would find a lot of use for tube amp players in many ways. Also, I've observed that most casual players would resort to pedals for their live sound anyway (myself included :P ).
But I agree - most iconic amps sound the way they do due to a lot of factors, among them the number of tubes, kind of components, and circuitry involved.
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I actually have a longstanding dream to DIY a circuit mating a 1-preamp tube front end to a 1-power tube output section, which I believe would find a lot of use for tube amp players in many ways.
Also, I've observed that most casual players would resort to pedals for their live sound anyway (myself included :P ).
Your intentions are good but it's already been done. Check the schematics of the valve junior, it is so simple and would fit your requirement except that there's no single power tube amp commercially available that can attain 30 watts of power.
I've been in your situation a couple of years back and owned a couple of amps during the process of finding a small yet versatile amp. I can name a few "low tube count" amps from the top of my head
Zvex Nano Amp
Ledford Moon rock
Epiphone Valve JR
Crate v18 / Blackheart
Peavey Windsor Studio
Marshall Class 5
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too long of a read but how i see it, tube amps are like shoes.. you just use them till they wear out (usually a very.. very long time...)..
once they do wear out and break, determine if it has been a very good, comfortable tool for you.. if it was, then you re-tube or have it resoled to be as sturdy as it was brand new, or simply discard the shoe or pass it to someone else to have them restore it to use.
look at the fender deluxe for example, low-mid wattage from some people but enough volume to fill a small bar. a lot of players swear by it and even after numerous breakdowns, they still op to have it fixed...
How come you don't see too much of those vintage "workhorses" in the form of it's solid state counterparts are i guess self explanatory.. either they're not worth it or they're just built too complicated (solid state IC's, LED's, etc...) to service.
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almost forgot,
always remember to have spare tubes and capacitors (filter caps: usually any electrolytic capacitor with 250V or more capacity)...
when one of these go bad, replace ALL as a set and keep the singles as spares. easier to ensure that you're gigging with a more stable set of parts for your tone...
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To add to the topic I started, here's an example of a "low count" tube amp that people seem to like a lot. I think Lazer carries the brand, too.
http://www.vhtamp.com/products/the-special-series/special-1220-combo
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i did use a blackstar ht5 for live use before..but at the end of the day, i will prefer my 1960 infinium
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counted ba si GOLDEA AT30 dito? with 3 preamp and 2 power tubes?
Really great amp. very loud and gig worthy.
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counted ba si GOLDEA AT30 dito? with 3 preamp and 2 power tubes?
Really great amp. very loud and gig worthy.
I think so paps haha :D
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how about hybrids? para preamp tubes lang.
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What you are suggesting is OK and all BUT tube preamp and power amp circuity is designed based on the sound a musician is after for.
For example, the JCM800 would have fewer preamp tubes (3 I think) and would only produce an overdriven/crunch tone. You'd need an OD pedal to boost the signal and overdrive the preamp to get metal tones.
Compare the JCM 800 to the Peavey 5150, with the Peavey you can easily dial-in heavy gain tones without an aid of an overdrive pedal (more preamp tubes).
The number of tubes in the power section allows the amp to be louder while maintaining clean headroom. For example, a twin reverb will always over power a reverb deluxe.
(clapping slowly)
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Please don't get the idea that I don't know what tubes do in their respective spots :-(
For example, channel 1 of the Fender Twin Reverb actual only needs one 12AX7 to drive the preamp, which makes it a really high-headroom design. In addition, the Fryette Sig:X series use two KT88s plus a phase inverter to produce 100 watts RMS of tube power. Of course the sound would be different compared to 4 EL34s or 4 6L6s working together, but it is what it is.
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Reading through the thread, I wonder if anyone has seen a single power tube amp that uses a KT88 [which I understand has more power than a 6L6]. That might work for a higher wattage amp with a low tube count.
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Reading through the thread, I wonder if anyone has seen a single power tube amp that uses a KT88 [which I understand has more power than a 6L6]. That might work for a higher wattage amp with a low tube count.
haha yeah I was supposed to include that piece of info sa original post, but it would make the message longer than it already was. :-D
A single KT88 run in single-ended class A mode can produce up to 20 watts of power. I actually found schematics on the web which had instructions on how to build such a power amp, but my understanding of circuits isn't too deep yet :(
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I realized one other thing that needs to be taken into consideration if you want maximum power from a single tube design: speaker efficiency. If you have a particular tone in mind that can only be delivered by a speaker that has low speaker efficiency, you're bound to go back to the power section and design it to deliver more wattage.
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Reading through the thread, I wonder if anyone has seen a single power tube amp that uses a KT88 [which I understand has more power than a 6L6]. That might work for a higher wattage amp with a low tube count.
I've used a KT88 on a Windsor Studio. It is a tad louder than the 6L6 but not loud enough. What is so cool with a single power tube amp is that you can crank the volume knob up to get power tube distortion without the deafening volume. Very good for recordings.
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Haha yup that's true. Although for cases like that you'd probably want something like a 4x12 cabinet paired to a hundred-watt head anyway, especially since a lot of the time low-efficiency speakers are also low-wattage ones (with many exceptions AFAIK). :-)
An interesting point is that two of Celestion's most popular speakers, the Blue and the V30, while on opposite sides of speaker wattage (the Blue is 15 watts, the V30 ~60 watts), are roughly of the same loudness (both 100db).
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@ts do you use the same amp for practice and playing out? how many times did you gig with that amp?
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I'd like to as soon as I get the chance to play semi-pro (and go back home to the Philippines, for that matter). Otherwise it's in my room serving as a reference "tube sound generator" for tweaking my effects (excellent at it too, I might add).
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I think for as long as the Amp has the sound I want/or looking for, the number of tubes does'nt matter.
As long as its pure tube, no matter how many, no diodes, then its perfect.
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May nakasubok na ng Goldea Classic 5? Looks like a 57/vibro champ sa unang tingin. Similar kaya ang tunog?
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Pawn Shop series Excelsior?
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Pawn Shop series Excelsior?
I have one. What do you want to know about it?
But if you want general impressions, here are my thoughts:
- i generally like combo amps with 12ax7 preamps tubes, and 6v6 power tubes. my first guitar tube amp is a vht special 6 combo. i liked its sound, so i sought for something more powerful that sounds similar to it. true enough, that's what the excelsior sounds like to me.
- its sounds like a tweed amp (middy, smooth clipping) with fat bass (due to the 15" speaker). not the typical fender scooped sparkling clean sound. good bluesy srv-type music, but probably not a good choice for modern hi-fi-sh sound, nor for tight distortion.
- its very loud, thanks to the efficiency of its 15" speaker. can jam along with a drummer for sure, but breaking up already (not completely clean)
- its has the frequency response to use as a bass amp too, but of course, at reasonable volume levels.
- beyond its "base" sound, it also uses tubes for its tremolo function. very lush/organic sounding tremolo, but cannot do the modern hard/chopper like tremolo sounds
- the common issue that most report is that its stock preamp tubes develop vibrations/rattling over time. once replaced, its good as new.
- this thing's a winner of blues and tweed sound are for you. and before i forget, i absolutely love its novelty retro looks :)
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siochi amplification has a new tube amp. I think its a 5 watter with just 1 preamp tube and 1 power tube. has a built-in attenuator so you can crank the hell out of it and get great rock tones. I don't know what he calls it because I've only tried it at its prototype stage.
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siochi amplification has a new tube amp. I think its a 5 watter with just 1 preamp tube and 1 power tube. has a built-in attenuator so you can crank the hell out of it and get great rock tones. I don't know what he calls it because I've only tried it at its prototype stage.
Does he have a website or fb page?
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wala na ata. maybe he got tired of everyone inquiring but not buying hehe. but he still makes amps and some "famous pedal"-clones. you can find his contact details on one of the threads about his amps
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siochi amplification has a new tube amp. I think its a 5 watter with just 1 preamp tube and 1 power tube. has a built-in attenuator so you can crank the hell out of it and get great rock tones. I don't know what he calls it because I've only tried it at its prototype stage.
Based sa anong amp model? May idea ka magkano?
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I have no idea saan nya binase...I think he was going for a very simple circuit with minimum parts that can sound "ok". just ask him hehe :)