Alternative To The EICO 1030 Regulated Power Supply - Page 1
Forum section: electronics / testgear

author: ZeusMC
author_rank: Contributor
timestamp: June 27, 2021, 10:43:37 am
content: Hello all,I've become interested in making guitar tube amplifiers. I have the Merlin Blencowe books and several other amp design, theory books.In this YouTube,How To Design A 12AU7 Gain Stage - Part 2 0:58 he is using a EICO 1030 regulated power supply.I'd like to know what alternatives to the EICO I could use, older and more modern ones?Thanks.

author: bob91343
author_rank: Super Contributor
timestamp: June 28, 2021, 02:13:48 am
content: I have a power supply that will do the job. Unfortunately, in this case, I am in Los Angeles.

author: ZeusMC
author_rank: Contributor
timestamp: August 07, 2021, 07:37:29 am
content: New to forum I missed your reply, sorry. Is it homebrew or a commercial unit?Thanks.

author: bob91343
author_rank: Super Contributor
timestamp: August 07, 2021, 11:01:49 pm
content: Commercial. Boat anchor type.

author: med6753
author_rank: Super Contributor
timestamp: August 08, 2021, 01:29:31 am
content: I don't think you are going to find a "modern" supply that will give you the voltages you need for vacuum tube work in one box. That's why in these videos you see old EICO or Heathkit supplies. They regularly come up on Ebay but unfortunately they do demand, and get, a high price.You could potentially build one up but finding a suitable power transformer that supplies upwards of 500V is like chasing a unicorn.

author: bob91343
author_rank: Super Contributor
timestamp: August 08, 2021, 03:43:33 am
content: Well if anyone is willing to pick up this heavy unit, PM me and we can discuss. If you are developing tube gear, it's a perfect solution, with several hundred volts variable, two outputs, considerable current, heater voltage, and two large meters.The EICO and Heath (and some others) do come up at swap meets. For a while it seemed that swap meets were coming back but now things have turned around and we have to wait again.This is not a pitch to sell a unit; I keep it just in case, and I like its looks. On the other hand, if someone could benefit from owning or borrowing it, I am open to that.While it's true that large transformers are expensive and rare, consider using one from a microwave oven. It could be repurposed either as is with a variac, or by rewinding the secondary. Its power level can be estimated from its weight or from the oven's nameplate. The need for heater voltage needs to be addressed separately. Many years ago I cannibalized power transformers from old black and white television sets. No fussing because they worked as is for my purposes.

author: 1audio
author_rank: Frequent Contributor
timestamp: August 08, 2021, 06:37:39 am
content: If you can get it this Heathkit is what you needhttps://www.ebay.com/itm/133760852955?hash=item1f24c4a3db:g:BcgAAOSw1JNgnvbo$240 or so. You may be able to find a Lambda 500V bench supply but those are rare and you will still need filament supplies and a bias supply. Its not cheap but building something similar will take a lot of time, especially since bench supplies need to be pretty rugged. They get shorted a lot.

author: james_s
author_rank: Super Contributor
timestamp: August 08, 2021, 06:43:03 am
content: I use a Heathkit IP32 that one of my teachers gave me way back in middle school, it's perfect for this sort of thing. About 10 years back my friend built an electrical clone of it that he's been using. Finding the transformer was the hardest part, although it isn't actually all that hard to wind a transformer yourself.

author: ZeusMC
author_rank: Contributor
timestamp: August 08, 2021, 09:31:15 am
content: Yes I saw that one, looks nice condition, excepting the dent in the front, reasonable post to UK and open to offers. I was watching a YouTube on restoring one.I'm friendly with the guys at my local garage and have a mechanist friend, who should be able to get the dent out, without messing up the appearance of the front panel.

author: ZeusMC
author_rank: Contributor
timestamp: August 08, 2021, 02:04:29 pm
content: When I started looking into power supplies I thought that something like this would do. Digital Programmable DC Power Supply 0-400V/1A Adjustable Power Supply 400W Ebay UK item number 303685316882 there is a 500V version available.I already have a 0-30V 0-10A Ebay 174823856718. I though I could use the above for the B+ and the 0-30V 0-10A for the grid voltage and get another for the heater voltage.I asked Randall Aiken, of Aiken amps about using this set up.He said, " Yes, a 500V 1A 500W supply should be more than plenty of power for anything you'll ever want to design. Just be careful, that is a lethal amount of voltage and current.Also, that supply is regulated and won't sag like a normal unregulated tube amp supply, so your power amplifier won't react like a "real" amplifier powered by a transformer supply that normally sags anywhere from 30V to 100V under full load.You can add a suitability-sized power resistor in series with the supply to emulate the sag.The problem is you won't know how much sag you need to emulate until you build the actual power supply you are going to be using in the real amp.Or you could take the "glass half full" approach and dial in the amount of sag you like with the power resistor and design the real amp power supply to have that much sag.Another issue is the regulated power supply will have zero AC ripple, but your real supply may have 10-20 volts or more of sawtooth AC ripple that varies with load. This can lull you into a false sense of security that you have designed a quiet amp, but when you build the real amp it may have hum and/or intermodulation. This also goes for using a regulated DC supply for your filaments if you are going to use AC filaments in the real amp."I won't be doing anything with high voltage until I really fully understand the theory and construction methods, turret, point to point etc.I bought the 0-30V 0-10A supply, also an inexpensive but good quality signal generator and a few other items. So I could follow along and take test measurements, Usagi Electrics safe low voltage tube projects on YouTubeI bought the dual channel low voltage dual DC power supply, so can get some practical experience, biasing grid, injecting various signals, measuring current and voltage etc.Vacuum Tubes: Episode 5 - The PentodeLet's Build a Low Voltage Vacuum Tube Audio AmplifierAlso bought a breadboard, breadboard tube sockets and some nos tubes.Merlin Blencowe has an article on running tubes on low voltage.Somebody else said, " You don't need a regulated supply to investigate tube behavior. I took a chassis and put four nine-pin sockets in it along with a variable unregulated power supply for the purpose of testing circuits. I've logged a staggering number of hours hovering over that thing while staring at a 'scope.

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 03:54:55 am
content: You do have to be careful when working with tubes. People who are used to modern solid state stuff don't tend to expect to have hundreds of volts and may not have developed the necessary safety habits. Not only that, the tubes get very hot, I've never gotten zapped by one but I have burned my fingers a couple times by touching a tube I forgot was hot.

author: bob91343
author_rank: Super Contributor
timestamp: August 09, 2021, 04:36:34 am
content: A common mistake is to forget about the heater wiring. Cold tubes generally won't conduct any current.

author: IAmBack
author_rank: Regular Contributor
timestamp: August 10, 2021, 09:33:10 am
content: I picked up BK Precision BK9185, really cheap.It was faulty, but the problem was with 1 dead MOSFET transistor, 2..3 blown-up resistors and SPD diode shorted, so it was repairable. Similar repair was performed on "signal path" channel (however, no SPD was installed AFAIR).I guessed values of resistors from other "channels"(it has 3+3 identical FET-s in identical configuration). Now my unit works fine, hovewer I don't use it oftenly as I rarely work with high(er) voltage devices.It is quite nice device, with fast OCP.It can be used up to 600V.