Plexi Palace dealer page - $159
Using a variac to correct voltage to 110 VAC - Plexi Palace
MCM Variac official product page - "10A Variable (Autotransformer). Gives you the ability to vary line voltage between 0-130VAC. Perfect way to safely troubleshoot power supplies, regulators, output sections, etc. Built-in ammeter shows current draw to help identify shorts before they can cause costly component failures. Replaceable fuse protection. Three prong grounded cord and socket provides convenience and safety. Order Number 72-110. Description: TRANSFORMER. 1 year warranty.. In stock. Currently in production. $99.95"
A variac is a power supply that goes between the wall socket and the guitar amp. It can reduce the supply voltage from 110 volts AC, or 140 volts in my house, to lower, such as 50 volts. This causes the power tubes to saturate at lower power levels. A related but even more powerful idea is that of Power Scaling, used in London Power amps (search the home page for "london").
MCM Electronics sells a variac. (800) 543-4330. MCM Electronics catalog 42B, page 176: Tenma 10A Variable (Autotransformer). 1 yr warranty. Varies line voltages between 0 and 130 VAC. Built-in ammeter shows current draw to help identify shorts. Fused design enables limiting current by changing fuse value (10A max). 3-prong graded cord and socket. Input: 120V, 60Hz. Output 0-130 VAC. Current: 10A, 1.3KVA. Fuse: 10A AGC (included). Non-isolated. Order # 72-110. Description: 10A Variable (Autotransformer). Ea: $99.95.
You might want to read all of the relevant postings, paying special attention to the ones relating to what happens to your filament voltages (assuming you want to use it on a tube amp that is) when you use the Variac. Some people recommend not using a variac on an amp you care about. Your results may vary.
You can buy a Variac from most any place that sells electronics test equipment. The Mouser catalog lists a couple, with the cheapest one being $425. Some people have built one for less.
Date: Wed, 18 Nov 1998 18:43:15 -0500
From: David Crippen
>My friend Victor Mason at the Plexi Palace in California (with some authority, I think) says that a Variac is easier on the tubes than a dummy load or attenuator, and the tone is more pure with less of the undesirable type of distortion. He particularly dislikes the tone product from the Marshall Power Brake. With the Variac, the volume and resulting tone can be more acurately titrated together and independently controlled. I am really happy with my Variac setup.
>Where can I get a Variac? I would sure like a product page URL to link to.
>Check with Victor Mason. He got me mine.
Victor Mason
Plexi Palace - specializes in the sale, repair, restoration and modification of vintage Marshall, Vox, Hiwatt, Park and Fender tube amplifiers.
21065 Bear Valley Rd. #2
Apple Valley, CA 92308
(888) 517-2166 toll free
(760) 961-8324
http://www.vintageamps.com
plexi at iguitar.com
I spoke with Victor. The Tenma brand variac has a current meter, variable output, with probably a 2 year warranty. $159 at Plexi Palace. Handles up to 10 amperes of electric current; a 100 watt Marshall only uses 4 amps. This is far less than the $400-800 typical price for a high-end, big-name variac such as Tectronics, B&K. For cathode-biased amps such as Fender Pro Jr. 15 watt amp with 2 6V6's, or VOX, he thinks a variac might not work. A variac can take a 100 watt Marshall plexi down to 5 watts, when you pull 2 tubes and run the variac at 55 volts. A variac works just with solid state rectifiers, not with tube rectifiers, because with a tube rectifier, the heater voltage gets reduced too. He offers the THD Hot Plate attenuator for $249. A variac is also good for amps that are meant for 105 or 110 volts, rather than 130 volts; 130 would damage the amp. He suggests using a variac and attenuator in conjunction. For a 15-watt amp, he recommends a power attenuator.
> I don't have any idea where we can get this variac. But I believe Eddie VH was using a variac that was made by "Homite Voltage Regulators" on his earlier VH albums.
Boelan wrote:
There are lots of resources on the net where you can find these things, such as: http://www.angela.com - call Steve. He'll be glad to help. Lot of the tube hi-fi places carry them. Word has it that it is not a great idea to be using these things unless you're really careful. Go to alt.guitar.amps and ask Ned or Lord Valve or one of those guys. They could give you more of the pro's and con's of using them as well as probably telling you where you can get one. And I'm sure they'll be happy to sell you a bunch of spare tubes and amp parts you might need in case the amp takes a dive.
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Messages 1-100 of about 1000 matches for search "variac":
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1. 98/10/29 022 Re: Marshall Power Brake ??? alt.guitar.amps D Dyer
2. 98/10/27 022 Marshall Power Brake ??????? alt.guitar.amps DBL/SRL
3. 98/10/27 022 Re: Marshall Power Brake ??? alt.guitar.amps Mark Amundson
4. 98/10/25 022 Re: "Cooking" caps advice alt.guitar.amps maniac
5. 98/10/24 022 FS:Bogner ecstacy head and c alt.guitar Sinasl
6. 98/10/24 022 Re: "Cooking" caps advice alt.guitar.amps DamnYankee
7. 98/10/15 022 Re: "3" Tubes? alt.guitar.amps QualityAna
8. 98/09/20 022 Re: Variac alt.guitar.amps SLaPCaTT
9. 98/09/15 022 Re: Variac alt.guitar.amps Dr. Anton Phibe
10. 98/09/10 022 Variac alt.guitar.amps SLaPCaTT
11. 98/10/21 021 Re: "Cooking" caps advice alt.guitar.amps QualityAna
12. 98/09/19 021 Re: Variac alt.guitar.amps stereo
13. 98/09/16 021 Re: Variac alt.guitar.amps ark
14. 98/09/15 021 Re: Variac alt.guitar.amps Tellyman
15. 98/09/15 021 Re: Variac alt.guitar.amps steve_2000
16. 98/09/15 021 Re: Variac alt.guitar.amps Dave the Dork
17. 98/09/14 021 FA: Variac & Weston Tube Tes alt.guitar.amps JRUBBO770
18. 98/10/27 020 Re: Amp emulators, speak#1/3 alt.music.4-track Michael
19. 98/10/27 020 Re: Amp emulators, speak#1/3 alt.guitar Michael
20. 98/10/17 020 Re: values of orange caps 71 alt.guitar.amps profrets
21. 98/10/15 020 Re: "3" Tubes? alt.guitar.amps Rich Koerner
22. 98/10/12 020 Re: "3" Tubes? alt.guitar.amps Ron Bales
23. 98/10/12 020 Re: "3" Tubes? alt.guitar.amps Danny Russell
24. 98/10/11 020 Re: "3" Tubes? alt.guitar.amps Tellyman
25. 98/10/10 020 Re: '73 Deluxe Rev bias alt.guitar.amps maniac
26. 98/10/10 020 Re: '73 Deluxe Rev bias alt.guitar.amps M P Gilbert
27. 98/09/20 020 Re: The DR STEREO TEST BENCH alt.guitar.amps dstork
28. 98/09/20 020 Re: The DR STEREO TEST BENCH alt.guitar.amps Lord Valve
29. 98/09/17 020 Re: self monitoring vari#1/2 alt.guitar.amps Lord Valve
30. 98/09/17 020 Re: self monitoring vari#2/2 alt.guitar.amps Lord Valve
31. 98/09/16 020 Re: Variac alt.guitar.amps Chip of Known S
32. 98/09/16 020 Re: The MAXI-MATCHER...a rev alt.guitar.amps Lord Valve
33. 98/09/16 020 self monitoring variac.. alt.guitar.amps Dave Slagle
34. 98/09/15 020 Re: The MAXI-MATCHER...a rev alt.guitar.amps dave slagle
35. 98/09/10 020 Re: Variac alt.guitar.amps Dr. Anton Phibe
36. 98/10/27 019 Re: Amp emulators, speak#1/3 alt.music.4-track Chris Gieseke
37. 98/10/16 019 Re: values of orange caps 71 alt.guitar.amps tedm
38. 98/10/10 019 Re: Eddies guitar makeup in alt.music.van-halen Ryan D Sheeler
39. 98/10/10 019 Re: "3" Tubes? alt.guitar.amps Ben Dover
40. 98/09/19 019 Re: The DR STEREO TEST BENCH alt.guitar.amps A Dougla6
41. 98/09/18 019 Re: The DR STEREO TEST BENCH alt.guitar.amps David P. Greenb
42. 98/07/27 019 Re: Mains switch as a variac alt.guitar.amps Punkerdubh
43. 98/07/25 019 Re: Mains switch as a variac alt.guitar.amps stereo
44. 98/07/25 019 Re: Mains switch as a variac alt.guitar.amps Alan Thompson
45. 98/07/23 019 Re: Mains switch as a variac alt.guitar.amps stereo
46. 98/07/23 019 Re: Mains switch as a variac alt.guitar.amps Tonefactor
47. 98/07/14 019 Re: Mains switch as a variac alt.guitar.amps stereo
48. 98/07/14 019 Re: Mains switch as a variac alt.guitar.amps Tonefactor
49. 98/07/13 019 Re: Mains switch as a variac alt.guitar.amps JuArKa97
50. 98/07/13 019 Re: Mains switch as a variac alt.guitar.amps stereo
51. 98/07/13 019 Re: Mains switch as a variac alt.guitar.amps Tonefactor
52. 98/07/13 019 Re: Mains switch as a variac alt.guitar.amps profrets
53. 98/07/12 019 Re: Mains switch as a variac alt.guitar.amps peatea
54. 98/07/12 019 Re: Mains switch as a variac alt.guitar.amps Lord Valve
55. 98/10/25 018 Re: Low-watt power-tube devi alt.music.4-track Michael
56. 98/10/19 018 Re: Groove tubes or NOS? alt.guitar.amps OR120
57. 98/10/12 018 Re: Eddies guitar makeup in alt.music.van-halen mike baker
58. 98/10/11 018 Re: Eddies guitar makeup in alt.music.van-halen Rob
59. 98/10/11 018 Re: Eddies guitar makeup in alt.music.van-halen Jonathan Krogh
60. 98/10/11 018 Re: "3" Tubes? alt.guitar.amps Alan
61. 98/10/08 018 Re: "3" Tubes? alt.guitar.amps Charles Thomas
62. 98/09/17 018 Re: The MAXI-MATCHER...a rev alt.guitar.amps Lord Valve
63. 98/09/16 018 Re: The MAXI-MATCHER...a rev alt.guitar.amps Jamie
64. 98/09/16 018 Re: The MAXI-MATCHER...a rev alt.guitar.amps Sisco.
65. 98/09/15 018 Re: The MAXI-MATCHER...a rev alt.guitar.amps Ned Carlson
66. 98/09/11 018 Re: Sovtek Collapse alt.guitar.amps Mark or Cyndi V
67. 98/08/22 018 Re: Super Reverb hum problem alt.guitar.amps Dr. Stereo
68. 98/08/14 018 Re: SneakPeek summary for al alt.guitar.amps Charles Thomas
69. 98/08/14 018 Re: SneakPeek summary for al alt.guitar.amps DB>)
70. 98/07/26 018 Re: Mains switch as a variac alt.guitar.amps nocturnal10
71. 98/07/25 018 Re: Mains switch as a variac alt.guitar.amps RonSonic
72. 98/07/23 018 Re: Mains switch as a variac alt.guitar.amps stereo
73. 98/07/23 018 Re: Mains switch as a variac alt.guitar.amps stereo
74. 98/07/23 018 Re: Mains switch as a variac alt.guitar.amps Ralph and Diane
75. 98/07/15 018 Re: Mains switch as a variac alt.guitar.amps pja105
76. 98/07/15 018 Re: Mains switch as a variac alt.guitar.amps RonSonic
77. 98/07/14 018 Re: Mains switch as a variac alt.guitar.amps stereo
78. 98/07/14 018 Re: Mains switch as a variac alt.guitar.amps stereo
79. 98/07/14 018 Re: Mains switch as a variac alt.guitar.amps Lord Valve
80. 98/07/13 018 Re: Mains switch as a variac alt.guitar.amps JuArKa97
81. 98/07/13 018 Re: Mains switch as a variac alt.guitar.amps pja105
82. 98/07/13 018 Re: Mains switch as a variac alt.guitar.amps RonSonic
83. 98/10/10 017 Re: Eddies guitar makeup in alt.music.van-halen Rob
84. 98/10/09 017 Re: '73 Deluxe Rev bias alt.guitar.amps M P Gilbert
85. 98/09/30 017 Re: Questions about "old" Ma alt.guitar.amps tesla
86. 98/09/26 017 Re: Questions about "old" Ma alt.guitar.amps Ritualee
87. 98/09/25 017 Questions about "old" Marsha alt.guitar.amps Stephen Seals
88. 98/09/24 017 Re: Music Man 112 - Opinoins alt.guitar.amps Punkerdubh
89. 98/09/24 017 Re: Music Man 112 - Opinoins alt.guitar.amps Richard Godon
90. 98/09/24 017 Re: Music Man 112 - Opinoins alt.guitar.amps Dave Moore
91. 98/09/15 017 Re: The MAXI-MATCHER...a rev alt.guitar.amps Lord Valve
92. 98/09/12 017 The MAXI-MATCHER...a rev#1/3 alt.guitar.amps Lord Valve
93. 98/09/12 017 Re: The MAXI-MATCHER...a#1/3 alt.guitar.amps KCA NOS Tubes
94. 98/09/12 017 Re: The MAXI-MATCHER...a rev alt.guitar.amps TubeGuy
95. 98/09/12 017 Re: The MAXI-MATCHER...a#1/3 alt.guitar.amps ark
96. 98/09/07 017 Re: EVH's Equipment on the L alt.guitar.amps Ryan D Sheeler
97. 98/09/01 017 Re: JCM2000 DSL vs vintage p alt.guitar.amps Steve
98. 98/07/13 017 Re: Mains switch as a variac alt.guitar.amps stereo
99. 98/07/13 017 Re: Mains switch as a variac alt.guitar.amps profrets
100. 98/07/12 017 Re: Get Edward Van Halen's A alt.guitar.amps Ben Decho
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