Does anyone have any experience to venture an opinion on the "Champ" transformers that Triode sells as compared to the Edcors? This will be for guitar and for hi-fi use. So, I guess the question is (a) how well do the Champs work for hifi, and (b) how well do the Edcors work for a small guitar amp? Any experience to suggest that either of them is not okay?
I have no experience with the "Champ" OPT, but if its faithfull to the original it wont be as suited to hifi as the Edcor. The Edcors work fine in a guitar amp, tone may differ. The Edcor has more bass response. It also offers a 40% tap.
The 5K ohm Edcor is more directly comparable, the difference in load will also have an (not necessarily bad) effect on tone, and one on power.
The 5K ohm Edcor is more directly comparable, the difference in load will also have an (not necessarily bad) effect on tone, and one on power.
I tested both of these and some others a while ago. The results are on this web page:
http://www.tubelab.com/BudgetOPT.htm
The triode units are the silver (metal cased) transformers seen in some of the pictures (on the right)
The short story is that the Triode unit is just too small to be used in a HiFi amp. The Edcor is only a few dollars more and absolutely blows the Triode unit away for HiFi use. I usually use the Hammond 125CSE for guitar amps because it has taps for every impedance from 2.5K to 10K ohms. This allows intentional mismatching for unique sounds. I used the Edcor on a guitar amp (KT88 SE) so that I could have a triode - UL - pentode switch, but I found that I rarely used the UL setting. I used triode for clean sounds and pentode for overdriven nasty sounds. I sold that amp over a year ago, and I haven't seen it since. I don't know how the new owner uses it.
I have had the Triode units sitting on the shelf since the testing, haven't found a use for them yet. They might be good for a Champ style amp if you are trying to replicate the saturated transformer sound that some Champs produced when overdriven. I have not had the time to build many guitar amps lately.
http://www.tubelab.com/BudgetOPT.htm
The triode units are the silver (metal cased) transformers seen in some of the pictures (on the right)
The short story is that the Triode unit is just too small to be used in a HiFi amp. The Edcor is only a few dollars more and absolutely blows the Triode unit away for HiFi use. I usually use the Hammond 125CSE for guitar amps because it has taps for every impedance from 2.5K to 10K ohms. This allows intentional mismatching for unique sounds. I used the Edcor on a guitar amp (KT88 SE) so that I could have a triode - UL - pentode switch, but I found that I rarely used the UL setting. I used triode for clean sounds and pentode for overdriven nasty sounds. I sold that amp over a year ago, and I haven't seen it since. I don't know how the new owner uses it.
I have had the Triode units sitting on the shelf since the testing, haven't found a use for them yet. They might be good for a Champ style amp if you are trying to replicate the saturated transformer sound that some Champs produced when overdriven. I have not had the time to build many guitar amps lately.
I have bought and used both the Triode Champ Trans, and The Edcor.
I had nothing but problems with the Triode units when used in the Champ Blackface AA764 circuit. All kinds of oscillation issues. A lot of other guys I know from other forums have had difficulties with that transformer also. It clearly does not work as a drop in replacement in most cases. It sounds very thin, poor bottom end and very limited power handling.
Now the Edcor comparatively is a magic Pill. It sounds HUGE, massive bottom end capabilities and very crisp well chimed highs.
They can be really pushed!
I ordered a dozen with leads instead of the Lug/tabs and they are very well built. For the few dollar difference your getting a 3-4X better transformer from Edcor hands down.
There is a pretty significant size difference also. The Edcor is about as big as the Hammond 125DSE.
That reminds me, I need to order a few more of these
I had nothing but problems with the Triode units when used in the Champ Blackface AA764 circuit. All kinds of oscillation issues. A lot of other guys I know from other forums have had difficulties with that transformer also. It clearly does not work as a drop in replacement in most cases. It sounds very thin, poor bottom end and very limited power handling.
Now the Edcor comparatively is a magic Pill. It sounds HUGE, massive bottom end capabilities and very crisp well chimed highs.
They can be really pushed!
I ordered a dozen with leads instead of the Lug/tabs and they are very well built. For the few dollar difference your getting a 3-4X better transformer from Edcor hands down.
There is a pretty significant size difference also. The Edcor is about as big as the Hammond 125DSE.
That reminds me, I need to order a few more of these
Changing the output impedance switch on the fly will leave the output open for a few milliseconds while the switch is in between taps. That is usually a big No - No with tube amps. You could use a make before break switch, if you can find one.
I built several "Turbo Champ" amplifiers that incorporated an impedance switch and a triode - pentode switch. I sold several of these amps. I told the users to always put the amp in standby before flipping any switches. These amps have been out there for about 5 years. The only failures have been cathode resistors in the output tubes. Use a 5 watt resistor.
http://www.tubelab.com/Turbo_Champ.htm
When I had one of these amps, I flipped switches on the fly all the time. The triode - pentode switch will make a big pop in the speaker, but nothing bad ever happened. All amps were SE, some operated as high as 450 volts of B+. YMMV
In theory the voltage will not run away in an SE amp if the amp never hits clipping even without a load. As soon as the optput tube is cutoff the voltage can rise to kilovolt levels. This usually results in fried OPT's and tube or socket arcs. Once an arc starts, it is fed by all of the energy available in the power supply. The principle is the same as an automotive ignition coil. It is a safe bet that a guitar amp will see clipping.
I put some similar switches on some 50 watt P-P amps and I did have problems. Running a 16 ohm cabinet on the 4 ohm tap and doing a Jimi sized acoustical feedback caused a "screaming" sound in the speaker. That turned out to be an arc across the tube socket from pin 3 (plate) to pin 2 (grounded filament). Oddly enough nothing was damaged despite multiple occurances. I saw another amp with a fried impedance switch and one blown 6L6. The speaker cable was damaged, so it may have been run into an open. The OPT survived.
I watched an Ampeg SVT burst into flames in the 1970's. The band had plugged this 300 watt tube head into a Traynor cabinet which could not handle the power. This was an outdoor show, so the volume was set on kill. About half way through their set, I could detect the sound of a voice coil coming unwound. A short time later the speaker went open and the fire gods descended on the Ampeg. OPT, power transformer, 3 6550's and several resistors were all toast. Someone had tin foiled the power fuse.
I built several "Turbo Champ" amplifiers that incorporated an impedance switch and a triode - pentode switch. I sold several of these amps. I told the users to always put the amp in standby before flipping any switches. These amps have been out there for about 5 years. The only failures have been cathode resistors in the output tubes. Use a 5 watt resistor.
http://www.tubelab.com/Turbo_Champ.htm
When I had one of these amps, I flipped switches on the fly all the time. The triode - pentode switch will make a big pop in the speaker, but nothing bad ever happened. All amps were SE, some operated as high as 450 volts of B+. YMMV
In theory the voltage will not run away in an SE amp if the amp never hits clipping even without a load. As soon as the optput tube is cutoff the voltage can rise to kilovolt levels. This usually results in fried OPT's and tube or socket arcs. Once an arc starts, it is fed by all of the energy available in the power supply. The principle is the same as an automotive ignition coil. It is a safe bet that a guitar amp will see clipping.
I put some similar switches on some 50 watt P-P amps and I did have problems. Running a 16 ohm cabinet on the 4 ohm tap and doing a Jimi sized acoustical feedback caused a "screaming" sound in the speaker. That turned out to be an arc across the tube socket from pin 3 (plate) to pin 2 (grounded filament). Oddly enough nothing was damaged despite multiple occurances. I saw another amp with a fried impedance switch and one blown 6L6. The speaker cable was damaged, so it may have been run into an open. The OPT survived.
I watched an Ampeg SVT burst into flames in the 1970's. The band had plugged this 300 watt tube head into a Traynor cabinet which could not handle the power. This was an outdoor show, so the volume was set on kill. About half way through their set, I could detect the sound of a voice coil coming unwound. A short time later the speaker went open and the fire gods descended on the Ampeg. OPT, power transformer, 3 6550's and several resistors were all toast. Someone had tin foiled the power fuse.
Hey,
My Buddy and I back in our garage band days used 300W SVT's for Lead and Rythum amps!
We regularly destroyed 8X12 Cabs with those amps. No Foil fuses though, We cut 16 penny nails with diagonal cutters to the correct length instead. Needless to say we had both amps fail along the way, One just smoked a lot, The other caught fire and we just watched in amazement. Back then we were getting those used for about $100 each. Had I only known then what I know now!
Trout
tubelab.com said:
Trout said:
Thank you gentlemen; I've copied and forwarded your postings to the man who yesterday tried to help me after the concert and disconnected one speaker when the amp still was playing a music. He got angry with me because I said him never ever do such things again (he was helping!!!). The music was quiet, and hopefully 100W guitar transformers are used in 25W vocal/Hi-fi amp so they can handle higher voltages.
I discovered at a young and stupid age that a volume control shaft is just the right size. In fact there used to be a replacement volume control that came with a scored shaft. You could just snap off the part that you didn't need with a pair of pliers. The left over piece fits in the fuse box of a 60's vintage car. My old Pontiac would blow the air conditioner fuse whenever it felt like it, so I put a "no blo" fuse in. I found the short a while later. It was the fan speed switch. After the switch had ceased to exist, I just wired it to high all the time.
Large wing nuts work too. I had a '72 Chevy (back when it was just a used car) with that upgrade. The wiring harness behind the fuse box started melting and smoking, so we opened all the windows to let the smoke out. The electric windows never closed again. In fact, I junked the entire car because, even though I would fix just about anything, I was not willing to replace a wiring harness. Oh well. It had a 402 big block in it which I wished I had saved....
Tweeker said:
They actually did a mythbusters episode on using .22 cal bullets as a fuse.
Supposedly, Some good ole boy(Stereotypical Redneck) actually shot himself in a rather sensitive area when the fuse/bullet went off.
It was actually a pretty funny episode.
It is actually an urban legend according to snopes, Source was a doctored newspaper posted on the web.
Bullet Fuse
Trout
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