Hello, I am in the process of sourcing parts for the "simple SE" on tubelab.com as I'm sure many of you are familiar with the site. I was wondering about the power transformer options out there. Just looking for a basic one, nothing fancy. According to Digikey they only have power transformers up to 250~ VAC, and from what I understand I need approximately 450-500 volts?
Thanks guys, its not my first electronics project, but my first tube amp.
Thanks guys, its not my first electronics project, but my first tube amp.
You didn't ask, but stick with the vacuum tube rectifier. Forget about the solid state FRED rectifier diodes.
Go with an Allied 6K7VG from www.alliedelec.com (far less expensive) or try a Hammond 374BX from www.tubesandmore.com ($$$, but possibly a higher quality transformer).
Go with an Allied 6K7VG from www.alliedelec.com (far less expensive) or try a Hammond 374BX from www.tubesandmore.com ($$$, but possibly a higher quality transformer).
Other options:
Angela Universal power transformer
120V/240V primary! 380-320-55 (bias tap) -0-320-380 at 200mA. 6.3VCT at 3.5A for power and input tube filaments! 5V at 3A for rectifier tubes. 5VCT at 1.5A for 300B filament.
Edcor XPWR110
Tube Amplifier Power Transformer, 120V, 60Hz to 800V CT & 6.3V
Edcor can custom build to your requirements.
Lots of options from surplussales
http://www.surplussales.com/transformers/HvLvTr-7.html
Many options at VT4C
http://www.vt4c.com/shop/program/main.php?group_id=7
and the have R-core power transformers
http://www.vt4c.com/shop/program/main.php?cat_id=55&group_id=7&hit_cat=
Angela Universal power transformer
120V/240V primary! 380-320-55 (bias tap) -0-320-380 at 200mA. 6.3VCT at 3.5A for power and input tube filaments! 5V at 3A for rectifier tubes. 5VCT at 1.5A for 300B filament.
Edcor XPWR110
Tube Amplifier Power Transformer, 120V, 60Hz to 800V CT & 6.3V
Edcor can custom build to your requirements.
Lots of options from surplussales
http://www.surplussales.com/transformers/HvLvTr-7.html
Many options at VT4C
http://www.vt4c.com/shop/program/main.php?group_id=7
and the have R-core power transformers
http://www.vt4c.com/shop/program/main.php?cat_id=55&group_id=7&hit_cat=
thx TY_Bower, I was going to go with the vacuum tube rectifier, the FRED I just ordered incase I couldn't get tubes. they were only a dollar a piece.
You mentioned the allied transformer, specd:
TRANSFORMER, PRI:110-120V, 50/60HZ, 750VCT @150DCMA, 5V @3A, 6.3A @ 5.0A, LEADS
I take this to mean input of 110-120V, output at 750V @ 150 milliamps in DC voltage? I'm not sure what the rest of that means though. I thought the simple SE ran on approximately 450-500 volts?
Sorry about the amount of questions.
Thanks again.
You mentioned the allied transformer, specd:
TRANSFORMER, PRI:110-120V, 50/60HZ, 750VCT @150DCMA, 5V @3A, 6.3A @ 5.0A, LEADS
I take this to mean input of 110-120V, output at 750V @ 150 milliamps in DC voltage? I'm not sure what the rest of that means though. I thought the simple SE ran on approximately 450-500 volts?
Sorry about the amount of questions.
Thanks again.
the 750 volts is actually 375-0-375. You will have a full wave rectifier, which is two diodes, one rectifying each winding with the centre tap going to ground. So, to work out your DC voltage, multiply 375 x 1.414 = 530 volts. You will get some voltage drop through the rectifier, so will probably get about 480-500 volts.
This transformer is what tubelab uses and he recommends. I use the hammond 300 series as I need the multiple input taps because we have 240 volts here in Australia. There quite a few threads on Simple SE builds here, take a look if you are building one. This is a great amp, love mine!
Cheers,
Chris
This transformer is what tubelab uses and he recommends. I use the hammond 300 series as I need the multiple input taps because we have 240 volts here in Australia. There quite a few threads on Simple SE builds here, take a look if you are building one. This is a great amp, love mine!
Cheers,
Chris
hows the handmade h841
http://www.hndme.com/productcart/pc/viewPrd.asp?idcategory=187&idproduct=1382
it'd help me save on shipping costs (30+$)
would the 300 - 300 be too low for usage?
thanks
http://www.hndme.com/productcart/pc/viewPrd.asp?idcategory=187&idproduct=1382
it'd help me save on shipping costs (30+$)
would the 300 - 300 be too low for usage?
thanks
Have you seen this page on the tubelab site? http://www.tubelab.com/AssemblyManualSimpleSE/TubesAndTransformers_SSE.htm
It lists the voltages and tubes and output transformers. The page looks blank when you get to it, you have to scroll down.
To answer your question, yes that transformer is usable. However, you will only get half the output power from your amp, and it costs about $30 more, than the recommended transformer.
Hammond 274BX or Allied 6K7VG.
It lists the voltages and tubes and output transformers. The page looks blank when you get to it, you have to scroll down.
To answer your question, yes that transformer is usable. However, you will only get half the output power from your amp, and it costs about $30 more, than the recommended transformer.
Hammond 274BX or Allied 6K7VG.
nukaidee said:
Neither do I, and the page does not display properly in Firefox either. Not mumbo-jumbo at all, just a table of expected output powers by tube type and specific operating conditions.
The Allied 6K7VG or 274BX series Hammond are solid recommendations however.. I would go with one of these two..
The table gives you some very important information, and answers many of the questions you are likely to ask. You do have to help yourself a little though.
The table starts with tube type, EL34, 6L6GC and KT88. For modest price and good output power, I would suggest EL34.
The next column is B+ voltage. This is the voltage from the power transformer after it has been rectified by either solid state diodes or valve (tube) rectifier. Rough calculation for DC voltage, as I stated above, is 1.4 x AC voltage for solid state and about 1.2 x AC voltage for valve rectifier, as they drop a few more volts. For the recommended transformers you are going to get between 450 and 500 volts B+.
The next column is load. In very basic terms, this is the specification of the output transformer. Most guys building this amp are using a 5000 (5K) single ended output transformer with an output impedance the same as your speakers (probably 8 Ohms). To answer your next question, I would recommend these:
Edcore GSXE at $31 or
Edcore CXSE at $84.
Vp is the voltage at the plate (anode) of the output valve.
Vk is the voltage of the cathode of the output valve. This is the bias of the valve.
Rk is the value of the cathode resistor. This resistor sets the bias voltage (Vk). I think 560R or 620R is good for EL34.
Ik is current cathode, Diss (idle) is the plate dissipation. Orange and red values are on the high side, black is within limits. Power out is the output power of the amp. Dist 2nd and 3rd are distortion figures for second and third order harmonic distortion. DF is damping factor.
Not gobbledy gook, very useful information...
The table starts with tube type, EL34, 6L6GC and KT88. For modest price and good output power, I would suggest EL34.
The next column is B+ voltage. This is the voltage from the power transformer after it has been rectified by either solid state diodes or valve (tube) rectifier. Rough calculation for DC voltage, as I stated above, is 1.4 x AC voltage for solid state and about 1.2 x AC voltage for valve rectifier, as they drop a few more volts. For the recommended transformers you are going to get between 450 and 500 volts B+.
The next column is load. In very basic terms, this is the specification of the output transformer. Most guys building this amp are using a 5000 (5K) single ended output transformer with an output impedance the same as your speakers (probably 8 Ohms). To answer your next question, I would recommend these:
Edcore GSXE at $31 or
Edcore CXSE at $84.
Vp is the voltage at the plate (anode) of the output valve.
Vk is the voltage of the cathode of the output valve. This is the bias of the valve.
Rk is the value of the cathode resistor. This resistor sets the bias voltage (Vk). I think 560R or 620R is good for EL34.
Ik is current cathode, Diss (idle) is the plate dissipation. Orange and red values are on the high side, black is within limits. Power out is the output power of the amp. Dist 2nd and 3rd are distortion figures for second and third order harmonic distortion. DF is damping factor.
Not gobbledy gook, very useful information...
lowtherdream said:
The lack of a 5 volt winding is inconvenient, and I think 800 volts center tapped is a bit too much. You have to be careful with the ratings on the power supply capacitors, and solid state rectification is really out of the question.
I'd be happier to see something in the 700~750 VCT range with a 5 volt winding rated for at least 2 amps - 3 would be even better. The 6.3 volt winding needs at least 3.5 amps, but there is usually plenty there.
If you really need to get your power transformer from Edcor (perhaps to save on shipping because you are purchasing your outputs from them?) maybe inquire about any of the following power transformers:
XPWR002, XPWR003, XPWR004, XPWR033
XPWR035, XPWR048, XPWR059, XPWR067
I would suggest having a switch and being able to select different cathode resistance then you can swap valves and find what you prefer. Do a search, I have listed how I did it in several threads here. For what it is worth, I have tried KT88, 6L6 and EL34 and prefer the EL34. Transformer runs much cooler too!
chrish said:
wont one of these work?
http://www.edcorusa.com/products/transformers/xse/xse15-4-5k.html
That is in fact the very transformer I have for my Simple SE, however, I have 4 Ohm speakers. Note the heading on that page says 5000 Ohms to 4 Ohms. 5000 is the reflected load to the output valve when you are driving a load (speaker) of 4 Ohms. These transformers are labelled XSE15-4-5K. XSE is the model type (X Single Ended), 15 is for 15 watts, 4 is for the speaker load (4 Ohms) 5K is the primary reflected impedance (5000 Ohms). If you do not know the impedance of your speakers I would guess 8 Ohms. To be safe you would be best getting an 8 or 6 ohm transformer. The frequency response for these transformers is 70Hz to 18,000Hz. I have active crossovers, so this is not a problem. When Tubelab did his experiments, and when i built my amp, it was this transformer or the CXSE. The GXSE is a new development for guitar amps and has a frequency response of 40-18,000Hz. They are physically larger than the XSE. If building again, this is the transformer I would use if building to a budget or the CXSE if I had some more coin.
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