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The output transformer is the heart of a valve amplifier. The right pic shows a stereo Leak amplifier. The two output trannys are rotated 90deg to the power mains tranny to avoid picking up induced hum from the mains tranny external magnetic field.
A 211 SE Triode Amp
Output trannys contribute most of the distortion in a valve amp and have a limited bandwidth. Valve amp manufacturers purchase trannys from transformer winding companies. Transformer winding is an extension of the fitting and turning industry. Few people working in transformer winding companies have a knowledge of electronics or valve amps. Most valve amp manufacturers have a basic academic understanding of output trannys, but often have a limited or incorrect understanding of the physics of transformers or how they are made.
Academic formulas for calculating the design of output trannys is available in many text books and web sites. There is no need for this page to repeat academic information that is readily available.
This page gives an overview of the physics that governs the performance of output trannys and helps give a perspective that academic text often omit. Output trannys are the highest cost and most labour intensive part of a valve amp to make. Each output tranny, depending on size, takes approx 1 to 2 hours to wind, assemble with laminations, heated in an oven, dipped in resin and baked overnight, cleaned, painted, external leads connected, dress caps fitted, packaged and sent to a valve amp manufacturer.
A tedious task to say the least. The right pic is a simple analogy of an output tranny. The amplified audio from the 2 output valves, push pull is in opposite phase deg.
Depending on the tranny design there may be 2, turns of wire in the Primary and 90 turns for the Secondary winding. The primary and secondary windings are isolated. The iron core is magnetised by the AC current in the primary winding and the AC magnetism is passed into the secondary winding generating an output Voltage to drive the speaker. The turns ratio between the windings adjusts the secondary Voltage. Only AC can pass through a tranny. It is not possible for DC to pass through a tranny.
Often the primary has slightly more mass. In the example tranny the primary has 2, turns of thin wire, whereas the secondary has 90 turns of thick wire. E I and C core.
The majority of power and output trannys in valve amps are E I construction. The right pic shows the thin E I mild steel laminations that are stacked together to assemble the core. The tranny next to the E I is a C core which can be used for the same size bobbin. Bobbins can be open or have a center division. The square shape of the E I laminations is not an efficient conductor of magnetism. E I mains power trannys are noticeably hot when touched.
C cores are an efficient conductor of magnetism, but C cores do not have an aesthetic square shape and are more difficult to mount onto a chassis.
C cores are mostly used in industrial electronics and were approx twice the cost of E I laminations. Today, C cores are only slightly more expensive than E I laminations and it makes no sense not to use the superior quality C core in all output trannys, including power trannys.Single-Ended Output Transformers Single secondary SE output transformers available with primary and secondary impedances of your choice within reasonable working values. Silver wire windings available at current market prices.
Designs to watts. Parafeed designs. High voltage designs. Primary current max based on 25Hz saturationselect one: 20ma. Power level maximum, select one: 3w, 5w, 10w, 15w, 20w, 30w, 40w, 50w, 75w, w. Secondary impedance single in ohms, select one: 4 - 6 - 8 - 12 - 16 - 32 6 ohms is for 4 and 8 and 12 ohms is for or others can be made. OR Multiple tap secondary impedances, select one combination: ; ; etc.
Secondary wire type: C - copper,PS - partial silver, S - solid silver. PS can be used only for single secondary transformers. However, with additional circuit improvements, an even higher degree of low IMD performance can be achieved. New winding techniques utilize partially progressive honeycomb primary windings which will offer a very low interwinding capacity. Order Examples: 3K, ma.
These are expensive and because of changing prices we can only give prices by quotes. Core size is based on the current through the primary, turns involved and impedance needed. Core size and secondary wire size will determine the power capability. Note: a watt transformer cannot have a 50ma primary.
Tube amplifier output transformers
Information needed to order single-ended output transformers: Impedance of primary Current through primary Expected power output Impedance of secondary s Note: No winding DCR requests.
A3 Transformers. Partial Silver Transformers.
Line Output. Power Supply Chokes. Special Use.The Audio Voice Newsletter. Show more Show less. Attention, all first-time or wanna be builders of single ended directly heated triode amps. A nice way to experiment with a single-ended SE triode amplifier. During my formative years I read about vacuum tubes, but always dismissed their use in audio, since the mighty transistor was far superior.
I can now honestly say that I prefer vacuum tube amps although I like tinkering with all types of audio gear. Of course, this linearity has a price: a high plate voltage. I had three goals in mind when I started this project. Second, the circuit had to be simple for sonic reasonsbut able to supply the full drive voltage to the grid.
Third, I wanted to keep construction simple for building purposesto encourage other do-it-yourselfers to try a based amplifier. I came across a few designs using and transmitting tubes. Some of the designs used choke loaded plates, while others used transformer coupling between voltage gain stages. All the designs had at least two gain stages. I found this unusual since the grid needed only about V p-p, which is moderate.
After tossing around the idea for a while, I decided to use one of my favorite circuits — a voltage amplifier direct-coupled to a cathode follower. You Can DIY! Read moreI think the was designed as w dissipation, not 75w.
There were VT-4B's made, I have at least a couple. Western Electric made them with that designation, with a graphite plate, as opposed to their more common but still rare metal-plate versions. Everything from metal-plate UV from the s through later diathermy-oriented ones, and many other versions, including european made Tungsram metal-plate, oxide-filament versions. Of course Western Electric had at least 3 or 4 versions of their own. FWIW -Ed. Hi Ed, thanks for the infos regarding this tube.
The plate dissipation is rated at W for Class B and C. For Class A a max plate dissipation of 75W is given in the datasheet. Best regards Thomas. Just a note: as you know better than me, Sir, those 75W quoted in the RCA datasheet the only one still available on the Internet as the absolute maximum for the plate dissipation, are to be regarded as the CCS rating.
I may guess that the ICAS value the one we should look at, nowadaysalthough formally unknown since the class A service wasn't usually quoted on TT manualsis - more probably that not - substantially higher just for example, since Western Electric stated a plate dissipation of 85W for class A service with reference to the WE Warmly, Marco.
Hi Marco, you can trust me on this: you don't want to run a in a single ended Class A amp higher than 75W. It will start to red plate. I mean sonic differences. From the construction point of view, I think the TFK was far superior, its structure is more rigid and, above all, much lighter, that for the business of war was very important.
Regards, Francisco. I never tried this tube since I don't have any.
I never saw an issue with the rigidness of s. These have been used for military purposes as well. The GE are very sturdy and well made. And if you did, what's your opinion with the results? Nice Job to your S. Hi Angelos, I have used the A as driver for the It is an even better choice than the VT25 since it allows a higher plate voltage and has more headroom.
I also used another as driver which gave the best results. The A comes in second. The 2A3 would provide less headroom as a VT25 and a lower mu which requires another gain stage. With a VT25 or A a 3 stage set up with inout transformer can give enough gain.
Hello Thomas, Very nice piece of work on the Tube. I have one of Toshi Kurashima's amplifiers that just arrived here in NY. This amplifier uses a Western Electric a pentode to drive the Scarborough Toronto, Canada.
We are half way coming up with at least two models. Like the rest of our line upits the best or nothing and its in its own class. Each comes with its own dedicated supply and DC feeding stage circuitry for best separation, stability and working consistency, as well cooling capability, finished with gold plated locking type ceramic tube sockets.
Instead of pumping it to over 20W like some manufacture would do. We want the most silky, the most refine type of sound quality that beyond people have heard with s. Not just for looks, but copper is a good conductive material - we measured it is quieter when compared to aluminum chassis, thus some say copper chassis does improve sound quality.
All we know is this extra thick gauge copper sheet that use to construct the chassis comes with an extraordinary price to fabricate too. Standard thickness for making our heavy duty chassis is. The thick top aluminum plate used for the are 1 decimal inches which is strong enough we can put 3 large transformers on it without any flex.
And same for the copper chassis, but high quality copper sheets are much more expensive. A Canada based manufacture in hifi tube amplifiers. View fullsize. This is our answer to all the rest of the high end amplifiers around the globe! Special attention is paid to the power supply, which delivered by HASHIMOTO with the most purequiet and seamless supply of power, with our unique dual input choke transformers arrangement and multiple design of over sized high quality power supply capacitors to ensure the best quality and efficiency of supply to the s.
Each comes with its own dedicated supply and DC feeding stage circuitry for best separation, stability and working consistency, as well cooling capability, finished with gold plated locking type ceramic tube sockets Dual high end Hashimoto CUT CORE Orient HIGH B Materials choke transformers for multiply step down, and provide a quiet yet full power deliveries For power, we will bias the to the lower power side at around WPC Pure Class A.Welcome to Hificollective, to create an account please register here.
Group A. The quality criteria for group A are 20Hz to 20KHz -1 to Group B. Mid-price range, these are typically 20Hz to 40KHz minus 1. Group C. All group C transformer come with copper frames as standard.
The copper shroud being non-magnetic improves not only RF influx, but also low-level behaviour as it does not short out the airgap on the higher permeable cores like the AN Ultra HiB and the nickel cores this is essential for optimal performance.
All Copper — Copper transformers have copper lead-out wires, Copper — Silver have copper wire on the primary and Audio Note silver lead-out wires on the secondary and silver naturally silver wire all round. Price is for ONE transformer! Prices are for ONE transformer. All the above transformers are supplied raw in the sense that they are unpotted and with flying leads. As a rule delivery of the above output transformers is from stock, but dependent on internal usage delivery time can occasionally occur, especially the new custom made AN Perma Nickel cores may be on very long delivery, which can be as long as 16 — 18 weeks, we will normally try to tell you if a transformer is not in stock how long the delivery is likely to be, but in the case of the permeable materials production processes are very complex and problematic, so just beware.
Welcome to Hificollective, to create an account please register here x. Continue x. Skip to main content. Size mm x mm x mm, mounting holes centre to centre 87 mm to 84 mm both sides. Big Picture:. TRANS with copper frames fitted. Audio Note copper shrouds.You need to save up resources to upgrade, and you should time when you perform the upgrades.
With that in mind, time your upgrades for a window on the calendar where the effect of missing the tool will be minimized or totally removed. Despite the back-to-nature vibe of the game, and the strong push towards an earthy low-tech existence in your new valley home, the television in your farmhouse is really useful. At minimum, you should at least check the TV every day for the cooking broadcast because there are many recipes in the game you can only learn by doing so.
Speaking of weather forecasts and rain, rain is your best friend. In the early game you need to farm to get resources and money, but farming with the beginning level watering can can be really time consuming and exhausting. If you overplant, you may quickly feel overwhelmed by how much farmland you have.
Rainy days are a sweet, sweet, relief from your farming responsibilities. Saw a cool cave you want to explore. Want to get to know the villagers better. Need to squeeze in some wood chopping to build up your supplies. A rainy day is a perfect day to do everything but farm, so when you wake up to the sound of thunder, pack your knapsack and get ready to explorethe day belongs to you.
When you first arrive in Stardew Valley, the very friendly mayor stops by to introduce himself. Many new players avoid the box because there has to be a catch, right. Put aside your suspicions, dear reader. Stardew Valley is wholesome and the mayor your patron saint. Despite the improbable economics, the hardy little guy hauls all the loot you put into the drop box and sells it for you each night. If you have a huge pile of crops you need to sell right now to fund important purchases, skip the box and take them to the appropriate store to sell them.
If you do have a silo, however, the wild grass you cut down become hay. First, you can move any building at a later date (with no penalty). Just visit the carpenter and pick a new spot. Mercifully (and with an improbable TARDIS like quality) upgraded buildings maintain the same footprint no matter how big the interior gets.
This means the modest starter barn takes up exactly as much space on your farm as the fully upgraded barn. Hands down, fishing is the most polarizing thing in the Stardew Valley player community.
First, treat the fishing mini-game more like a dance and less like a click-spamming endurance challenge.
Instead, click slowly at first and watch the fish behavior. The more you fish, the better you get at it (both in terms of game playing skill and in-game skill points) and the catch bar gets bigger.