HQ stuff like my Douk DAC which lived 4 hours before it got hot and smoked and similar lifetime for a SMSL headphone amp - but thankfully a transformer should at least last a while. Do they use old soup cans for the lams ? (joking but still -)
Feverishly baked into my sarcasm. I would not expect these to be good for HiFi applications, except maybe at headphone power levels, but they may be OK for a guitar amp in the 5 watt range since a guitar with standard tuning contains no frequencies below 82 Hz, nor much above 5 KHz.
I was thinking somewhere along those lines. I have created a new output stage design that presents a low impedance source to the OPT bring out the best in an OPT. It works quite well in push pull amps that use a cheap 70 volt line matching transformer as the OPT. Matching transformers don't do well in SE applications because of the DC current.
The picture shows a popular Champ replacement OPT that I got from Triode Electronics in 2004. It looks like it could get it's butt kicked by a 12AX7, and weighs in at a whopping 205 grams, 15 of which is in the wires. Despite their midget status they did OK in a small amp that used a 12AX7 and a 6AQ5 for about 3 watts.
Amazon states the weight of their OPT's at 600 grams. They have been notoriously wrong about size and weight of their stuff since they came into existence, so I expect that 600 g is probably at best a SWAG.
I will test them against the tiny Triode transformers, an old Edcor XSE15-8-5K (777 g), and a few other small transformers I have in a box using the UNSET circuit with probably a 6W6GT.
I'm gambling on the fact that they stepped up to melted down Toyotas.
Sorry George. I should have been more clear. I ordered and received my pair from China (quite some time ago) and I have weighed them. So the 990g is a fact, not a speculation nor a "specification".
I really do hope to get my SSE running (thanks again for all the help) so I can compare these Chinese jobbies to the Transcendars.
I really do hope to get my SSE running (thanks again for all the help) so I can compare these Chinese jobbies to the Transcendars.
I realize that the transformers I ordered from Amazon are not the same as the set you have. They are however bigger than the Triode "Champ replacement" transformers for less money, so it's an $18 experiment in my mind. I'm sure that I can make a useful guitar amp with it, and that's why I only ordered one.
Makes sense.
And on that note, I have always wanted to build a bass amp. I have an electric bass that I have never learned to play and maybe (a big maybe) if I built an amp it would inspire me to finally get started. Can you point me in the direction of a reasonably simple bass amp build with low/moderate power?
These Chinese OPTs are just going to sit here otherwise. I mean, even if they are "okay" in the SSE, I know I will switch back to the Transcendars - even if it is only because I spend so much money on them.
And on that note, I have always wanted to build a bass amp. I have an electric bass that I have never learned to play and maybe (a big maybe) if I built an amp it would inspire me to finally get started. Can you point me in the direction of a reasonably simple bass amp build with low/moderate power?
These Chinese OPTs are just going to sit here otherwise. I mean, even if they are "okay" in the SSE, I know I will switch back to the Transcendars - even if it is only because I spend so much money on them.
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The transformers I ordered from Amazon along with some cheap digital meters for a TSE experiment have disappeared into Amazon's distribution network. They were scheduled to arrive at my house on Saturday but didn't. Now the delivery date is "unknown."
'Bass amps" actually have a broader definition than "guitar amps" so some narrowing of scope is needed. A bass guitar is usually tuned one octave below a regular guitar, and the two smallest strings are missing. This puts the lowest note at roughly 41 Hz, but some players tune lower.
Playing styles range from "just thumping out the bass line" to super dynamic percussive styles from jazz and funk music..
Playing a simple bass line requires a limited dynamic range and a frequency response form 40 Hz to about 1 kHz.
Trying to play like Victor Wooten requires a whole lotta dynamic range and frequency response from DC to light. Slapping the strings around produces some subsonic artifacts that tend to cause saturation in the OPT if not filtered out first. "Harmonic" playing produces tones beyond the typical range of the instrument. Those players typically run high powered class D amps with some digital effects. Check out the frequency range he gets out of a bass guitar here. Note the solid state amp and 10 inch speakers used to reproduce those high notes:
SOLO BASS: Victor Wooten Performs “Amazing Grace” | Huckabee - YouTube
I looked at the OPT's you have in the picture in post #16 of the SSE thread. I'm guessing that they will pass 5 watts or so at 40 Hz without undue saturation. Saturation causes an increase in tube current, and sustained operation in saturation causes excessive tube wear and possible failure.
5 watts for a bass guitar is not considered loud or powerful, but a lot of that depends on the speaker.
A 15 inch Eminence Legend bass guitar speaker claims a 99 dB sensitivity, but is in the low 80 dB range at 40 to 50 Hz. A similar 10 inch Legend has a 91 dB sensitivity, but is in the high 70's at 40 to 50 Hz. Both have resonant impedance peaks below the normal bass guitar range so the speaker's impedance rises to over 20 ohms at 41 Hz. This means that your 5 watt 8 ohm amp will clip before you ever get 5 watts out of it into 20+ ohms.
I have a little guitar amp that makes 4 watts on a good day. It's connected to a DIY cabinet that contains a pair of cheap 6 inch PA speakers. Their stated sensitivity is 93 dB and they are about 82 dB at 40 to 50 Hz. These were never intended for guitar, or bass guitar, but they do fine for routine practice and do get a "turn it down" response from my wife upstairs. I have a cheap Chinese copy of a Fender bass. It plays far better than I do. Short fat fingers limit my reach to about 3 frets on the long neck bass.
The little amp is seen here sitting on top of the speaker cabinet. I made it almost 4 years ago and still haven't made a proper cabinet yet. It is a lot louder with a regular guitar, bit I'm using a $4 OPT and speakers that have very limited response below 80 Hz.
It would be possible to make a bass guitar amp in the 5 watt range with one of your transformers. I would start with a Fender Champ type circuit and tweak some of the parts values in the tone control area to suit your particular bass guitar sound preferences. I made several "Turbo Champs" in the late 1990's and one did get used for bass guitar. It ran a pair of 6 X 9 inch car speakers obtained when a local K-mart closed down.
If you get nowhere trying to get a replacement for your Hammond transformer, it may be possible to use it in a bass amp with a solid state rectifier.
'Bass amps" actually have a broader definition than "guitar amps" so some narrowing of scope is needed. A bass guitar is usually tuned one octave below a regular guitar, and the two smallest strings are missing. This puts the lowest note at roughly 41 Hz, but some players tune lower.
Playing styles range from "just thumping out the bass line" to super dynamic percussive styles from jazz and funk music..
Playing a simple bass line requires a limited dynamic range and a frequency response form 40 Hz to about 1 kHz.
Trying to play like Victor Wooten requires a whole lotta dynamic range and frequency response from DC to light. Slapping the strings around produces some subsonic artifacts that tend to cause saturation in the OPT if not filtered out first. "Harmonic" playing produces tones beyond the typical range of the instrument. Those players typically run high powered class D amps with some digital effects. Check out the frequency range he gets out of a bass guitar here. Note the solid state amp and 10 inch speakers used to reproduce those high notes:
SOLO BASS: Victor Wooten Performs “Amazing Grace” | Huckabee - YouTube
I looked at the OPT's you have in the picture in post #16 of the SSE thread. I'm guessing that they will pass 5 watts or so at 40 Hz without undue saturation. Saturation causes an increase in tube current, and sustained operation in saturation causes excessive tube wear and possible failure.
5 watts for a bass guitar is not considered loud or powerful, but a lot of that depends on the speaker.
A 15 inch Eminence Legend bass guitar speaker claims a 99 dB sensitivity, but is in the low 80 dB range at 40 to 50 Hz. A similar 10 inch Legend has a 91 dB sensitivity, but is in the high 70's at 40 to 50 Hz. Both have resonant impedance peaks below the normal bass guitar range so the speaker's impedance rises to over 20 ohms at 41 Hz. This means that your 5 watt 8 ohm amp will clip before you ever get 5 watts out of it into 20+ ohms.
I have a little guitar amp that makes 4 watts on a good day. It's connected to a DIY cabinet that contains a pair of cheap 6 inch PA speakers. Their stated sensitivity is 93 dB and they are about 82 dB at 40 to 50 Hz. These were never intended for guitar, or bass guitar, but they do fine for routine practice and do get a "turn it down" response from my wife upstairs. I have a cheap Chinese copy of a Fender bass. It plays far better than I do. Short fat fingers limit my reach to about 3 frets on the long neck bass.
The little amp is seen here sitting on top of the speaker cabinet. I made it almost 4 years ago and still haven't made a proper cabinet yet. It is a lot louder with a regular guitar, bit I'm using a $4 OPT and speakers that have very limited response below 80 Hz.
It would be possible to make a bass guitar amp in the 5 watt range with one of your transformers. I would start with a Fender Champ type circuit and tweak some of the parts values in the tone control area to suit your particular bass guitar sound preferences. I made several "Turbo Champs" in the late 1990's and one did get used for bass guitar. It ran a pair of 6 X 9 inch car speakers obtained when a local K-mart closed down.
If you get nowhere trying to get a replacement for your Hammond transformer, it may be possible to use it in a bass amp with a solid state rectifier.
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Cool looking amp George.
How does the 1K resistor switch on the power tube screen grid affect the output/tone?
I'd like to try using those switchable cathode bypass cap switches on an amp, too.
Apologies for hijacking this thread, but I recently finished a 6L6GC guitar amp that I "modded" by adding an extra gain triode (adjustable by using a 5751 or 12AX7, etc) and a 500K gain pot. It is very loud! I had to take it to a local recording studio to crank it.
How does the 1K resistor switch on the power tube screen grid affect the output/tone?
I'd like to try using those switchable cathode bypass cap switches on an amp, too.
Apologies for hijacking this thread, but I recently finished a 6L6GC guitar amp that I "modded" by adding an extra gain triode (adjustable by using a 5751 or 12AX7, etc) and a 500K gain pot. It is very loud! I had to take it to a local recording studio to crank it.
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Well, it looks like that I will not be testing the Amazon OPT after all. It was supposed to arrive on Sunday (Prime Shipping) but did not.
Tracking shows it left New Jersey with Amazon's private shipping partner en route to the USPS. It never got to the USPS.
Today I was given a choice to accept a refund, or have a new one sent, but when I tried to choose "send new one", I was told "that option is not available' so I accepted a refund for the package. Unfortunately, they only refunded the transformer, not the 5 meters that were also in the package.
It is impossible to get a human on the phone at Amazon.....pass the buck time.
While looking up transformers on Edcor's web site I found that they now offer small SE OPT's with wires on them, so I'll probably get one of the $25 OPT's to test. The exposed push terminals are not safe on top of the chassis with grandkids around.
Tracking shows it left New Jersey with Amazon's private shipping partner en route to the USPS. It never got to the USPS.
Today I was given a choice to accept a refund, or have a new one sent, but when I tried to choose "send new one", I was told "that option is not available' so I accepted a refund for the package. Unfortunately, they only refunded the transformer, not the 5 meters that were also in the package.
It is impossible to get a human on the phone at Amazon.....pass the buck time.
While looking up transformers on Edcor's web site I found that they now offer small SE OPT's with wires on them, so I'll probably get one of the $25 OPT's to test. The exposed push terminals are not safe on top of the chassis with grandkids around.
You might end up getting those Amazon transformers anyway, George. Stranger things have happened.
I AM serious about being successful. A successful electrical engineering design project of any kind begins with a set of goals. Many of the projects here center on a design with "best possible sound" or something similar as the primary design goal. That however is NOT the only possible design goal for all projects.
Working in cell phone design taught me that total product cost is ALWAYS in the top five goals and pennies count when you are making a million phones a month. Things like "how much does it cost to place a single part on a PC board" must be measured and updated monthly. A successful design engineer must investigate all possible options whenever cost is a design consideration, and scrutinize them when cost is a primary goal.
There was a long running challenge on diyAudio to design a low cost vacuum tube guitar amp. Cost was the PRIMARY design goal for this challenge. It is now a sticky here:
The Hundred-Buck Amp Challenge
The power and output transformers are vital components for such a design, and creative repurposing was used a lot in those designs. Dropping over $50 for the transformers does not leave much for the rest of the amp, when it ALL must cost under $100. The guitar amp I use most often was designed in that thread and features a $4 OPT and a $15 power transformer, both from China, and neither of which were intended for a vacuum tube amp. It is currently the only working guitar amp that have at the moment, meets all of the criteria I set forth in the redesign, and I consider it quite successful. The total product cost at the time it was built was under $50.
Finding a cheap OPT for a Single Ended vacuum tube amp is not so easy since it must use a gapped core. Power and line matching transformers may work OK for push pull, but not SE. An $18 OPT for a SE tube amp is worth investigating.
Would I consider these OPT's for a HiFi amp where sound quality is the primary goal? NO. They are not worth consideration for that application.
Will I consider them for a low buck guitar amp that could be built for under $100? Absolutely, and anyone who doesn't is NOT serious about being a successful amp designer. The posts in question were discussing them for use in a 5 watt guitar amp, a place where they might just be the most optimum choice.....as I said, an $18 experiment.
My design goals are mostly for a High Fidelity with some ample guts amp.
That does not include anything "single-ended", a 50C5 or a single 6V6 - those are for someone else to play with...
And for something inside a portable phonograph.
What I mean for "guts" is enough clean power to drive a decent set of home speakers with some power to spare at reasonable volume levels in a home environment.
Not some monster watt amp, nor some 28 speaker tower, either.
I mean reasonable power like 15 to 60 clean watts/channel.
My one main tube amp uses a PP set of EL84's, driven by 6EU7's in cathodyne configuration.
It's a competant performer for sure, at "only" 17w/ch.
But enough to bring my floorstanding Advent Maestro's to attention, and alert my neighbors that "oh lord, he's playing that stereo again!"
As for costs, I lay down a budget, with the knowledge that I don't want to go "cheap" if I'm gonna live with it - it's after all a one-time investment.
And I stay away from chinese transformers - I've heard and seen too many horror stories.
I'd sooner go vintage and USA Made for that stuff, tubes too.
That does not include anything "single-ended", a 50C5 or a single 6V6 - those are for someone else to play with...
And for something inside a portable phonograph.
What I mean for "guts" is enough clean power to drive a decent set of home speakers with some power to spare at reasonable volume levels in a home environment.
Not some monster watt amp, nor some 28 speaker tower, either.
I mean reasonable power like 15 to 60 clean watts/channel.
My one main tube amp uses a PP set of EL84's, driven by 6EU7's in cathodyne configuration.
It's a competant performer for sure, at "only" 17w/ch.
But enough to bring my floorstanding Advent Maestro's to attention, and alert my neighbors that "oh lord, he's playing that stereo again!"
As for costs, I lay down a budget, with the knowledge that I don't want to go "cheap" if I'm gonna live with it - it's after all a one-time investment.
And I stay away from chinese transformers - I've heard and seen too many horror stories.
I'd sooner go vintage and USA Made for that stuff, tubes too.
Those are YOUR goals and preferences for HiFi equipment.
Just because other DIYers have different goals, design a wide variety of projects each with it's own different goals, just want to tinker, or want to try out an idea to see if it's worth pursuing in a budget friendly manner, doesn't mean they aren't serious about being successful.
I also have a very nice sounding Single Ended amp with a single 6V6 in each channel for 2 WPC. It sounds best when paired with smallish high efficiency horn speakers like FH3's. It was built with all US or Canadian (the power transformer) components at a time when I had the money to buy what I wanted for nearly everything I built. That doesn't make it "not a serious design" or "something inside a portable phonograph."
I have been experimenting with music synthesizer circuitry of my own design. Much of this experimentation deals with "first pass prototypes" that have only existed in computer simulations. Am I not serious because I use cheap Amazon sourced materials for these prototypes knowing that many will wind up in the box of dead ends to be robbed of some of their parts as needed, or hacked up beyond recognition to extract all useful information that can be learned from them before entering the box of dead ends?
Sure it was nice working at Motorola where I had a PC board fab, a machine shop, a pick and place SMD assembly line, and a full stockroom all within a 5 to 10 minute walk.
Now that I'm retired and on a fixed budget, my DIY projects will continue to use Amazon, Ebay, and direct order from China parts, where the budget and design goals warrant.
Oh, and I can get 17 WPC out of a pair of 50C5's in each channel with HiFi specs too. It survived the 12 hours at full power test without issues.
Just because other DIYers have different goals, design a wide variety of projects each with it's own different goals, just want to tinker, or want to try out an idea to see if it's worth pursuing in a budget friendly manner, doesn't mean they aren't serious about being successful.
I also have a very nice sounding Single Ended amp with a single 6V6 in each channel for 2 WPC. It sounds best when paired with smallish high efficiency horn speakers like FH3's. It was built with all US or Canadian (the power transformer) components at a time when I had the money to buy what I wanted for nearly everything I built. That doesn't make it "not a serious design" or "something inside a portable phonograph."
I have been experimenting with music synthesizer circuitry of my own design. Much of this experimentation deals with "first pass prototypes" that have only existed in computer simulations. Am I not serious because I use cheap Amazon sourced materials for these prototypes knowing that many will wind up in the box of dead ends to be robbed of some of their parts as needed, or hacked up beyond recognition to extract all useful information that can be learned from them before entering the box of dead ends?
Sure it was nice working at Motorola where I had a PC board fab, a machine shop, a pick and place SMD assembly line, and a full stockroom all within a 5 to 10 minute walk.
Now that I'm retired and on a fixed budget, my DIY projects will continue to use Amazon, Ebay, and direct order from China parts, where the budget and design goals warrant.
Oh, and I can get 17 WPC out of a pair of 50C5's in each channel with HiFi specs too. It survived the 12 hours at full power test without issues.
All well and fine there.
Except that I don't make amps, or anything, that lasts 12 hours.
George,
Do NOT feed trolls!
After all that you have accomplished in your life - professionally, personally, at Tubelab.com and here at DIYaudio - and all the other things I have no idea about - you have no obligation to suffer the BS of self-proclaimed "wise people".
I hope you know how many thousands of people you have helped and educated over the years. This is only a rough approximation on my part, but it doesn't take a rocket scientist to figure it out.
Please do not respond to grumpy attention ****** (trolls) any more. You are better than that. Use the ignore function of this forum if necessary.
Do NOT feed trolls!
After all that you have accomplished in your life - professionally, personally, at Tubelab.com and here at DIYaudio - and all the other things I have no idea about - you have no obligation to suffer the BS of self-proclaimed "wise people".
I hope you know how many thousands of people you have helped and educated over the years. This is only a rough approximation on my part, but it doesn't take a rocket scientist to figure it out.
Please do not respond to grumpy attention ****** (trolls) any more. You are better than that. Use the ignore function of this forum if necessary.
I realize that I took the troll bait....whether the comments were purposely stupid, or not, I don't know, but definitely misguided and likely misunderstood.
Everyone is entitled to their own opinion and preferences in what they build. Calling someone "not serious about being successful" when they are using good product engineering practices to choose the correct component for the chosen product within its given design constraints, just displays lack of understanding.
As the big manufacturers have already learned, the only way to compete against the influx of sub $200 vacuum tube guitar amps on the market is to use similar components AND build them overseas.
At least two other posters in this thread mentioned guitar amps, an application where this type of OPT may do just fine. Again, a good guitar amp can be built right out of the Tubes And More catalog, they will even sell you a kit. it will be a clone of a Fender Champ, or other well known classic, just like some of the $200 Chinese amps on Amazon. Want something different, use something different, AND be creative in looking for it.
I don't either, I used to build amps for sale, they were reliable and well regarded. I publish my designs for people to use freely as they see fit. I sell PC boards for my designs, although some choose to build them with PTP construction. I can't control what someone else does with my design, and some builders use them in manners that I never imagined. Before I publish a design for public consumption I test it thoroughly under extreme conditions to find possible shortcomings in the design. Again, this is just good engineering.
All of my amp designs including HiFi amps like the SSE, TSE, and SPP get to eat my lousy guitar playing while driven more than 20 dB beyond clipping, and they will be run for 12 hours at full power with a continuous sine wave at high line voltage. I will also find the point of maximum output tube dissipation and test it there for possible heat buildup issues.
I mentioned that previously because nobody expects a pair of 50C5's to put out 20 watts at 3% THD, much less do it for 12 hours continuously. The amp in question will be a guitar amp, and get to eat my guitar playing forever, so such testing is needed. So far it has survived everything I throw at it on 340 volts of B+, WITH its $5 cheap Chinese line matching transformer for an OPT and $16 Chinese power transformer.
I will not justify good engineering practice any further, some people will never get it.
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