That's an insanely good deal!
The deal is not so good this side of the border, the same module goes for more than $304.73 at Mouser Canada. The huge price increase isn't from the exchange rate conversion, which would only raise it to maybe $105 CAD. Oh, well, it's not as though I need a six hundred watt power amp!
That said, I am quite interested in the "good tube preamp into clean solid-state power amp" concept. It's hard to ignore the whopping advantages of the new solid-state class-D audio power amp modules!
I think you've already answered that question!
-Gnobuddy
Marshall? Wouldn't you want 9 pin outputs?
I was planning on 12V6's for my Fender inspired design.
Why on earth does the number of pins on the bottle matter? That's just mechanical packaging. At audio frequencies, it has no effect on the way the valve works.
So as long as sockets to match the base are available, any valve base is equally good for audio.
I avoid valves with Magnoval and Loctal bases for that reason (can't easily find sockets to match, and don't want Novar sockets permanently damaged by Magnoval valves).
As an aside, the packaging does matter at radio frequencies, where small amounts of stray inductance and capacitance become significant, and large physical size becomes a definite disadvantage.
-Gnobuddy
All of the amps that put the Marshall name on record covers and concert stages had EL34's in then except the Marshall Major which ran KT88's. The EL84 amps came along quite a bit later. Fender did tend toward the 6V6 and 6L6 types, but that had more to do with which side of the pond they were on than anything else.
I once made a statement that "EL84's rock, but 6V6's were born to sing the blues." You can make either tube sound like the other by playing with loading, drive, and voltages, but the 6V6 has about half the emission capability of the 6BQ5 (EL84). This makes it saturate sooner, and less abruptly than the 6BQ5. You can get that creamy smooth bluesy saturation out of a 6V6 far easier that most other tubes.
Here, we can stick anything from an old radio tube to a TV sweep tube into our amps and make whatever we want........don't like it, try a different tube.
Part of the reason that little 4 watt amp I made sounds so good has to be related to the wimpy output tubes. There is only 3.5 watts of heat in those cathodes. When I made the first prototype using a bench power supply, I didn't like it. I tinkered with it for several days, lost my patience and decided that it was going to get "death by power supply." I cranked the B+ on those little "150 volt maximum" tubes up to about 350 volts. They couldn't even pass enough current to blow themselves up! That experiment did tell me that they did need more voltage, less current, and a much lighter load. Now they sound really good for 4 watts!
The 6V6 has less than 3 watts of heat in it's tiny little cathode. Same deal feed it some voltage, and run a light load. Fender totally abused the plate voltage spec in some of their 6V6 based amps.
I was going to use 15CW5's with a 15V or 16V brick with a 25W OT from a Wurlitzer organ that used to have 7868's but the Hammond transformer is smaller and therefor lighter. Might just be a pound but every once counts. The wood for the cabinet was from a board that was considerably lighter than the average at Home Depot. Originally I was going to just do a tube preamp and a PWM amp section with a FV-1 chip for reverb.
Might have got down to 15 lbs, really hate to give up the cabinet for a heavier combo but such is life. The speaker is a Yamaha that was an organ pull. Their upper line of organs had some pretty good speakers that sound nice with guitar. The one I am using is a 30P23 which I know nothing about but it weighs 5 lbs. I have a Yamaha JA3083 (40W) that comes in at 6 lbs and a JA3052B that is 8 1bs (60W). Of course the 8 lb one just sounds better than any speaker I have, but it adds another 3 lbs. I could make up for the weight going PWM on that one, hmmm... ...I may have to think about this one.
Ha, yes thanks for the education, I was a teaching assistant for microwave lab while in
graduate school, LOL!
By 9 pin I meant pentodes of the EL84, etc. variety that were in the 18W Marshall amp.
People here will tell you about cheap versions with odd ball heater voltages if you are nice.
My point was a small Pentode rather than a small Beam Power tube.
Here is my ugly prototype that works with 5881s or 6V6s, plan was to use 12V6s in the
final, cheap, version. From way back in this thread and I think I just made the $100 budget:
http://www.diyaudio.com/forums/inst...ndred-buck-amp-challenge-160.html#post4298404
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Then why not say so? People have a better chance of understanding you if you say what you mean. Cryptic posts will not be understood. Nobody can read your mind.
And both beam tetrodes and true pentodes come in 9 pin packages, you know. Saying "9 pin" does not equal saying "pentode".
-Gnobuddy
On this thread we've already discussed the use of an inexpensive boost-mode switching DC-toDC converter to generate B+ voltage for valves (MagiDeal DC-DC Boost Step-up ZVS High Power Module Converter 45~390V Single Output: Amazon.ca: Home & Kitchen).
We've also discussed the use of something like a cheap 19V laptop power supply to drive it. These are easily found for a few bucks each at local thrift stores nowadays.
The remaining issue has been valve heater power; there aren't many valves with 19V heaters, so the laptop power supply is out, or a separate power supply for heaters alone is needed.
I think the heater power issue may now have a very easy solution: DROK(R) DC-DC High Power Buck Voltage Regulator Board 5-40V to 1.2-36V 12V/24V to 5V 12A Adjustable Step Down Volt Converter Module Battery Power Supply Transformer for Car Vehicle Adjustable Power Supply LED Lights: Amazon.ca: Home & Kitchen
With a claimed 100W rating, this DC-DC converter is more than beefy enough to power all the valve heaters in any sane guitar amp, and it can be set to put out anything from 1.2 V to 36 V DC, so you can use just about any oddball valves you want to.
I have a feeling I may have already bought my last conventional 60 Hz power transformer for a valve amp.
-Gnobuddy
We've also discussed the use of something like a cheap 19V laptop power supply to drive it. These are easily found for a few bucks each at local thrift stores nowadays.
The remaining issue has been valve heater power; there aren't many valves with 19V heaters, so the laptop power supply is out, or a separate power supply for heaters alone is needed.
I think the heater power issue may now have a very easy solution: DROK(R) DC-DC High Power Buck Voltage Regulator Board 5-40V to 1.2-36V 12V/24V to 5V 12A Adjustable Step Down Volt Converter Module Battery Power Supply Transformer for Car Vehicle Adjustable Power Supply LED Lights: Amazon.ca: Home & Kitchen
With a claimed 100W rating, this DC-DC converter is more than beefy enough to power all the valve heaters in any sane guitar amp, and it can be set to put out anything from 1.2 V to 36 V DC, so you can use just about any oddball valves you want to.
I have a feeling I may have already bought my last conventional 60 Hz power transformer for a valve amp.
-Gnobuddy
We all do that, some designs just look better on paper than the others.
To me, that's the crux of the problem with the competition - there are just way too many variables to consider, so the outcome probably leads to no where.
Well, the actual competition ended some time ago and there was no clear cut winner. As with anything today there are often too many choices to make a reasonable decision on what to buy or build. This thread, and a few others should help a builder decide where to start.
There were several periods in my life where I built amps for sale, of gifts. HiFi and guitar amps, tube and solid state. Often the hardest part of all of it is to figure out what the prospective customer wants. With guitar amps, I would tell the person to grab his favorite axe and we would do a road trip to Sam Ash, the Guitar Center, or Ace Music. Try lots of amps and tell me what you like and dislike about each one.
Today we have YouTube. True you can't (or shouldn't) make a purchase decision based on YouTube videos, but you CAN eliminate a lot of choices. We can and do offer the same experiences here.
A perspective amp builder should be able to gain some insight from the discussions here, even if it's just to decide if a certain build is within his construction capabilities. It should also be possible to make some judgments on build choices from the text surrounding a particular design. When I refer to a certain design with the words "heavy metal racket," an acoustic or rhythm player can probably rule that out, as will a shredder rule out many amps that only have a clean channel.
There will always be a bias surrounding any amp purchase, build or construction choice, just as there would be if you took the same guitar and player into two different music stores to hear the same amp. Having a professional musician endorse or judge an amp might influence some people, but probably only a few, and only those who aspire to sound like that pro.
The real "judge" needs to be the person building or buying an amp. Only they know what they want. It is up to us to present our designs in the most transparent manner.
This forum does a good job of educating a perspective builder as to why an amp may sound the way it does, and how it works. This serves to assist a perspective builder to learn for himself what he wants and why.
The outcome leads wherever you want it to. If you are serious about building something, you read, learn, and eventually take your best shot at a first amp. Then discuss it here, and with other members help, eventually tweak, and morph it into whatever you really want.
There is a player for every (working) amp, and an amp for every player. I have made amps that I didn't like. Often I took them apart, or gave them away.
I made a dozen or so "Turbo Champs" back in the 90's. All were similar, but different. Different tubes, transformers, and speakers were used, and all were minimal dollar amps based on a Fender Champ design. Many used car speakers purchased for around $5 or less when the local Kmart closed down.
I made one with a pair of 5 X 7 inch JBL car speakers that I pulled out of my car before trading it in. I didn't like it, and neither did anyone else. It sounded too clean and lifeless, so it sat in our music room being used as a practice amp for my daughter's keyboard (Roland JV1000) for at least a year. One of my daughter's friends plugged his ES335 into that amp, and he was in love. I must admit that combination did sound good, so I gave him the amp.
There were several periods in my life where I built amps for sale, of gifts. HiFi and guitar amps, tube and solid state. Often the hardest part of all of it is to figure out what the prospective customer wants. With guitar amps, I would tell the person to grab his favorite axe and we would do a road trip to Sam Ash, the Guitar Center, or Ace Music. Try lots of amps and tell me what you like and dislike about each one.
Today we have YouTube. True you can't (or shouldn't) make a purchase decision based on YouTube videos, but you CAN eliminate a lot of choices. We can and do offer the same experiences here.
A perspective amp builder should be able to gain some insight from the discussions here, even if it's just to decide if a certain build is within his construction capabilities. It should also be possible to make some judgments on build choices from the text surrounding a particular design. When I refer to a certain design with the words "heavy metal racket," an acoustic or rhythm player can probably rule that out, as will a shredder rule out many amps that only have a clean channel.
There will always be a bias surrounding any amp purchase, build or construction choice, just as there would be if you took the same guitar and player into two different music stores to hear the same amp. Having a professional musician endorse or judge an amp might influence some people, but probably only a few, and only those who aspire to sound like that pro.
The real "judge" needs to be the person building or buying an amp. Only they know what they want. It is up to us to present our designs in the most transparent manner.
This forum does a good job of educating a perspective builder as to why an amp may sound the way it does, and how it works. This serves to assist a perspective builder to learn for himself what he wants and why.
The outcome leads wherever you want it to. If you are serious about building something, you read, learn, and eventually take your best shot at a first amp. Then discuss it here, and with other members help, eventually tweak, and morph it into whatever you really want.
There is a player for every (working) amp, and an amp for every player. I have made amps that I didn't like. Often I took them apart, or gave them away.
I made a dozen or so "Turbo Champs" back in the 90's. All were similar, but different. Different tubes, transformers, and speakers were used, and all were minimal dollar amps based on a Fender Champ design. Many used car speakers purchased for around $5 or less when the local Kmart closed down.
I made one with a pair of 5 X 7 inch JBL car speakers that I pulled out of my car before trading it in. I didn't like it, and neither did anyone else. It sounded too clean and lifeless, so it sat in our music room being used as a practice amp for my daughter's keyboard (Roland JV1000) for at least a year. One of my daughter's friends plugged his ES335 into that amp, and he was in love. I must admit that combination did sound good, so I gave him the amp.
AES used to have a "generic" push pull OPT for about $10.....those days are gone. I haven't tried any of their newer stuff.
I used to get good transformers from Musical Power Supplies when they were located in Florida. I believe he was having them wound in one of the Caribbean islands (Haiti maybe?). He has since moved, and his transformers are now USA made, but the prices are considerably higher. I haven't tried any of the new ones, but other amp builders like them.
OT20PP USA Output transformer 25VA & 8K/6K6 to 4/8/16 ohm | eBay
Musical Power Supplies, Inc. - Home
There is also Triode Electronics. They have a bunch of US made guitar amp transformers including this:
ClassicTone # 40-18002 Fender Deluxe Style 20W Output Transformer 8 Ohm
OUTPUT TRANSFORMERS - MADE IN USA
Again, I haven't used any of their new stuff except the tiny Fender Champ OPT. They used to have some other cheap OPT's that worked pretty good for the bucks.
I still have a stash of "80 VA" guitar amp transformers that I bought almost 20 years ago. During that time I have only managed to blow one up, but it was a most spectacular fireball. That happens when you are sucking over 150 watts through a transformer made for about 60 watts, running it on 700 volts, and your load resistor blows letting all that power rip through the OPT with nowhere to go except into flames.
After that I bought two 8 ohm 500 watt load resistors.....haven't blown them yet.
I used to get good transformers from Musical Power Supplies when they were located in Florida. I believe he was having them wound in one of the Caribbean islands (Haiti maybe?). He has since moved, and his transformers are now USA made, but the prices are considerably higher. I haven't tried any of the new ones, but other amp builders like them.
OT20PP USA Output transformer 25VA & 8K/6K6 to 4/8/16 ohm | eBay
Musical Power Supplies, Inc. - Home
There is also Triode Electronics. They have a bunch of US made guitar amp transformers including this:
ClassicTone # 40-18002 Fender Deluxe Style 20W Output Transformer 8 Ohm
OUTPUT TRANSFORMERS - MADE IN USA
Again, I haven't used any of their new stuff except the tiny Fender Champ OPT. They used to have some other cheap OPT's that worked pretty good for the bucks.
I still have a stash of "80 VA" guitar amp transformers that I bought almost 20 years ago. During that time I have only managed to blow one up, but it was a most spectacular fireball. That happens when you are sucking over 150 watts through a transformer made for about 60 watts, running it on 700 volts, and your load resistor blows letting all that power rip through the OPT with nowhere to go except into flames.
After that I bought two 8 ohm 500 watt load resistors.....haven't blown them yet.
During the last few days, I came across several interesting things worth sharing on this thread.
First, a commercial product family - the VOX MV50 guitar amplifiers: MV50
These are palm-sized (literally), deliver 50 watts RMS into a 4 ohm speaker, and use a "Nutube" in the preamp.
You may have heard about "Nutubes" a year or so ago. They are a new type of vacuum triode valve built in the format and packaging of old-fashioned VFD displays - that's "vacuum fluorescent display", like the blue or orange ones used on millions of home Hi-Fi and home-theatre amplifiers for the past three decades.
While the physical arrangement of electrodes and glass envelope in a Nutube is different than the valves from the first half of the 20th century, these things are real, honest-to-goodness valves, with metal electrodes in a vacuum housed inside a glass envelope.
One of the ideas we've been kicking around on this thread lately is combining a valve guitar preamp with a solid-state class D power amplifier, and that is exactly what the VOX MV50 family is. They are priced at $200 in the USA at the usual vendors, and, most importantly, several of the online clips sound pretty good to my ears, especially for the "clean" model. They do not sound cold, thin, and sterile in the way most solid-state guitar amps do on the clean setting.
Here is an example: VOX(R) MV50 - CLEAN Demo - YouTube
One more: YouTube
The original Hundred Buck Amp Challenge had some wind let out of its sales when a $100 commercial product - a Chinese-made Champ clone - went on the market. I don't know if the VOX MV50's will have a similar effect, but certainly, if someone wants a small, light, reasonably "valvey" sounding guitar amp, without the bother of building their own, it would be tempting to just go buy one of these.
Those of us who prefer to DIY, however, now have a benchmark of sorts to shoot for. Can we pair a 50-watt class D module from Ebay and a $1 valve or two from ESRC, and come up with something that sounds at least as good as the VOX MV50 family?
I'm betting we can, and that we can do it for a lot less than $200, though probably not in an equally small physical package. Which hardly matters to me, because once the amp is the size of a small lunch-box, further shrinkage doesn't bring a whole lot more convenience, unless you can get it all the way down to stomp-box size and put it on your pedalboard with your effects.
-Gnobuddy
First, a commercial product family - the VOX MV50 guitar amplifiers: MV50
These are palm-sized (literally), deliver 50 watts RMS into a 4 ohm speaker, and use a "Nutube" in the preamp.
You may have heard about "Nutubes" a year or so ago. They are a new type of vacuum triode valve built in the format and packaging of old-fashioned VFD displays - that's "vacuum fluorescent display", like the blue or orange ones used on millions of home Hi-Fi and home-theatre amplifiers for the past three decades.
While the physical arrangement of electrodes and glass envelope in a Nutube is different than the valves from the first half of the 20th century, these things are real, honest-to-goodness valves, with metal electrodes in a vacuum housed inside a glass envelope.
One of the ideas we've been kicking around on this thread lately is combining a valve guitar preamp with a solid-state class D power amplifier, and that is exactly what the VOX MV50 family is. They are priced at $200 in the USA at the usual vendors, and, most importantly, several of the online clips sound pretty good to my ears, especially for the "clean" model. They do not sound cold, thin, and sterile in the way most solid-state guitar amps do on the clean setting.
Here is an example: VOX(R) MV50 - CLEAN Demo - YouTube
One more: YouTube
The original Hundred Buck Amp Challenge had some wind let out of its sales when a $100 commercial product - a Chinese-made Champ clone - went on the market. I don't know if the VOX MV50's will have a similar effect, but certainly, if someone wants a small, light, reasonably "valvey" sounding guitar amp, without the bother of building their own, it would be tempting to just go buy one of these.
Those of us who prefer to DIY, however, now have a benchmark of sorts to shoot for. Can we pair a 50-watt class D module from Ebay and a $1 valve or two from ESRC, and come up with something that sounds at least as good as the VOX MV50 family?
I'm betting we can, and that we can do it for a lot less than $200, though probably not in an equally small physical package. Which hardly matters to me, because once the amp is the size of a small lunch-box, further shrinkage doesn't bring a whole lot more convenience, unless you can get it all the way down to stomp-box size and put it on your pedalboard with your effects.
-Gnobuddy
Posts on tube emulation and special speaker EQ deserve their own thread and have been moved Not quite as simple, but nearly so - here's Fred Nachbaur's (RIP) compressor from his "Spunky" guitar amp. The speaker signal is rectified and fed back to the control grid of the input pentode (half of a 9JW8).
I would have thought modulating G1 with DC would cause all sorts of thumping and bumping noises at the anode, but apparently it worked well enough for Mr. Nachbaur (and maybe his wife, whom he built the amp for.)
-Gnobuddy
