Frequently Asked Questions.

Page Last Updated 02 Mar 2010.

Home Page and Contact Details.

Contents

If none of the above items seem to fit try using Edit/Find(on this page) with suitable words.

All our FAQs are on this one page.
You can scroll or use the link tables scattered through the page.

[1] Price and delivery

[1.1] General Pricing Notes

Where do I find the latest price?

Price on web site is the definitive price. If you call us for a price we look it up on the web!
If a product has a price on a datasheet and a price available from the calculator or the UK price list you may take the lowest relevant price.
Note that the prices on the datasheet and UK price list have VAT and carriage included.
UK price is in pounds for delivery in UK.
Euro price is in Euro for delivery in Mainland Europe.

You have changed the price since I placed my order. What do I pay?

All orders are fulfilled at the price on the order.
However you may use a web price for up to a month after it changes.
Please add a note on your order to indicate that you are taking advantage of this offer.
If no price was quoted then latest price at the time of payment transaction is used.

You quoted a price different from the website. Why?

This may be because we are preparing an update to the website and have used the new price to quote.
Use the lowest of quoted or website.
Please add a note on your order to indicate that you are taking advantage of this offer.

I want lots of transformers. Can I get a better price?

For larger quantities we can quote a special price.
Please E-mail us.

Note that we cannot accommodate alternative pricing structures on Paypal orders yet.

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[1.2] Delivery Information

How long do I need to wait for delivery of my order?

We normally carry a small stock of most types. Stock however may be kept at a partly made level and require varnishing etc. In some cases we get several orders together for a particular type and have to make to order. For these reasons you should allow up to four weeks for delivery.

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How do you send goods?

We use one of the following methods:

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What happens during a postal strike?

We use one of the following methods:

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[1.3] Product Price Notes

Why is there a large difference in price between styles?

There is a considerable difference in manufacture cost between different mounting styles. The reasons are shown below.

U-clamp price is lower than other prices. Why?

All winding wires are connected to tags during winding. A single clamp with no fixings is used.

Frame mounting is more expensive than U-clamp. Why?

All winding wires are connected to tags during winding. Two frames are used with studs, nuts etc.

Drop through is more expensive that U-clamp. Why?

Bobbin has to be modified to fit within metal shroud. Some wires have to be terminated within the winding and additional flying leads fitted. Studs, nuts etc are required.

Fully Shrouded with Feet is much more expensive than other styles. Why?

Bobbin has to be modified to fit within metal shroud.
All wires have to be terminated within the winding and additional flying leads fitted.
This is very time consuming during winding and test.
Two shrouds are used with studs, nuts etc.

Larger transformers do not seem to have the big difference in price between styles. Why?

Some larger transformers do not have tags fitted on the bobbins.
All wires have to be terminated within the winding and additional flying leads fitted.
This is very time consuming during winding and test.
These are therefore higher priced for all possible variants.

What is the price for a Kit and what do I get?

We have discontinued Kits at present while we set up a new pricing structure for alternative combinations.

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[1.4] Customer Locations

You have a price calculator but it does not show the product or my location.

This feature is new. Not all data is setup yet.
As product data is added the datasheet price will also change as we altered our price formula in Feb 2005.
Check dates on datasheets to see if this has occurred yet.
If your location is not there yet - Email us and we will add it.

I do not live on the Mainland UK. How much do I pay?

Check below to see if your location is mentioned.
See also our Price Calculator page.
Follow links from Home page.

I live on the Isle of Man. How much do I pay?

Special export prices available. Email for details.

I live on the Channel Isles. How much do I pay?

Special export prices available. Email for details.

I live on the Isle of Wight. How much do I pay?

We are based on the Isle of Wight so can offer reduced carriage charge.
Product can be collected from our factory by arrangement.

I live in the Eurozone part of Europe. How much do I pay?

Prices are in Euros.
Price to retail customers include UK VAT and EU carriage.
Price to VAT registered customers exclude VAT but include EU carriage.
The EU price on the data sheets (where shown) is for VAT registered traders in the Eurozone.
This system will change shortly.

I live in Switzerland. How much do I pay?

Prices are in pound sterling. Price exclude VAT but include EU carriage. Email us for details.

I live in the USA. Can you supply me?

We are not able to supply to North America at present for legal reasons.

I live in Canada. Can you supply me?

We are not able to supply to North America at present for legal reasons.

I live in a country you have not listed. Can you supply me?

Email for details or prices.

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[1.5] Payments

How can I pay?

PayPal/Credit card/Debit card are our preferred methods.
Mastercard. Visa. Switch. Maestro. See 'Payments' page.
Call us and place your order by telephone. Leave a message on Voicemail or Email us and we will call you back.
Use Our On-Line price calculator and order via PayPal.
For details of the PayPal system use PayPal.com or PayPal.co.uk.
DO NOT EMAIL YOUR CREDIT CARD DETAILS. Our site is not secure. Cheque with order is also acceptable.

When do you bank my cheque or credit card?

We do not normally bank your payment until your transformers are tested.
This is normally a few days before despatch.
However Pay-Pal transactions are passed to the banking system or credit card company within a few days of placing the order.

I need a VAT receipt. How do I get one?

Just ask by Email or Telephone or on your order.

If you have one, put your VAT number on your order or Email it to us before despatch.
We will supply a till receipt or invoice with our VAT number.
Formal order account customers will get a computer generated invoice.
We can E-mail the invoice in HTML format.
Our VAT number is shown on our Home page.

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[1.6] Product Availability.

Where have some of your products gone?

Some of our Products require special components, materials or processes.
If these are not available or likely to take a long time we will remove affected products from the website. We may also remove products which are time consuming but infrequently sold to allow a better flow of other products to satisfy a higher proportion of customers.

What products are affected at present?

What products or changes are you planning to introduce?

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[2] Product Technical

[2.1] General Technical Notes

How do I get more technical information on a transformer?

General parameters are indicated on the individual data sheets.
Typical default values are shown below.
We hope to upgrade the datasheets gradually.

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[2.2] Mounting style Restrictions

Why are small transformers only available in U-clamp?

For some smaller sizes the only mounting style available is U-clamp. This is due to our supplier not making frames and shouds for smaller sizes.

Why do large transformers not have U-clamp mounting styles?

For larger sizes the U-clamp is not available. This is due to a limitation on the mechanical strength of the U-clamps available.

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[2.3] Connections

I have received a transformer but I can't identify the connections.

Wire connections are identified by colour.
Pin numbers are defined by the bobbin manufacturer.
The data sheet (on the website) defines the pin numbers.

Pin numbers are embossed on the bobbin near the pins.
These can be difficult to read, particularly when varnished.
The trick is to alter the lighting of the transformer until the embossing is readable.
We will be adding a page to the website with a diagram of pin positions.

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[2.4] Specifications

Specifications (Push Pull Output Transformers)

Default information unless stated otherwise on data sheet:

Specifications (Single Ended Output Transformers)

Default information unless stated otherwise on data sheet:

Specifications (Mains Transformers)

Default information unless stated otherwise on data sheet:

Specifications (Chokes)

Default information unless stated otherwise on data sheet:

How do you determinine Output Transformer Impedances?

Secondary Impedances are defined by the Loudspeaker manufacturer.
The impedance value varies by frequency with a resonance at the low frequency end.
Impedance is typically specified at 1kHz.
Typcal common values are:


We have defined a standard set for most of our transformer to cover the range:

Primary impedances are determined by a combination of Valve data and Circuit Design.
For Single Ended circuits Valve data usually specifies a suggested impedance load as Ra.
For Push-Pull circuits Valve data usally specifies a suggested impedance load as Raa.
However datasheets and circuit designs are not consistent in this information. Some say Ra when they mean Raa, some say Ra for one of the two valves.
Valve data often gives a series of alternative impedance figures.
We try and use the most commonly accepted figure by amplifier designers.
The transformers are designed to match impedances on each side. This is done by matching the square of the turns ratio.

Examples:

How do you determine Push-Pull Output transformer Primary connections.

Most of our push pull transformers are wound in several sections. These have been adjusted to provide tappings for Ultra Linear operation. For a winding of 2000 turns anode to anode the winding would be:

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[2.5] Special and Custom Transformers and Chokes

Special versions

We offer a wind to specification service.
This service is popular and is usually operating at full capacity.
This service uses the same resources as Rewinding.
A typical waiting time will be as listed on the Rewinds page.

I want a transformer for a circuit that I can send you. Can I send the circuit?

To reduce overloading please do NOT send us large pictures of circuits etc unless agreed.
We will normally give you a special email address.
These large files may block our ISP server for several days.

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[2.6] Rewind and Replacement Transformers and Chokes

Rewind

We offer a rewind or replacement service.
This service is popular and is usually operating at full capacity.
A typical waiting time will be listed on the Rewinds page.
If a time is not listed then assume from 6 months to 2 years!
DO NOT send us transformers unless agreed.
Please add full name, address and contact details securely to transformer.
We have a number of transformers for rewind without any details.
If you have sent us a transformer and not received any progress reports recently then contact us.

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[2.7] Part Numbers, Sales Codes and Drawing Numbers

The numbers on the delivery notes or labels are confusing.

Normally we would provide Salescode, Drawing number and Internal order.

Our sales codes are in the format VXX123456. These refer the designs which are given drawing numbers in the format DXX12345-0000.

A cross reference between a drawing number and salescode is given near the bottom of each data sheet.

Special and Rewind transformers are allocated a drawing number only.

Internal Orders are four our use only are are in the format AXX12345.

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[2.8] Products undergoing Design Changes.

What products are likely to change in the near future?

We have finished changing products as a result of material supply and machine process problems.
We may have minor corrections to connections and data.

What if I want a Transformer to Match or Replace an earlier design?

We keep the design of all earlier issues on File and can make to special order. There may be a charge for this service.

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[2.9] Safety

How safe are your Transformers

See also LVD Directive below.
We use high quality professional materials.
Mains transformers use separate sections for Primary and Secondaries.
Insulation between windings is a composite of Nomex and Polyester tapes.
All except certain rewinds (where we meet the original specifications), or very small transformers (where we use an appropriate voltage) are tested at the equivalent of 4000 VRMS.
All materials are UL approved. We also do our own flammability tests on combinations of varnish and winding materials.
Any faults are rigorously investigated within our FRACAS system.
All our products are made within our ISO9001 - Quality Management System. We meet all the technical requirements to enable us to CE mark our products.

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[3] EU and International Directives

[3.1] Low Voltage Directive

Do you meet the LVD (Low Voltage Directive)?

We meet the requirements of Directive 73/23/EC
Specification EN60950 is used as a detailed interpretation.

Yes - in all respects.

Are your transformers safe?

We comply with all the relevant sections of EN61558.

Mains transformers are double insulated.
No metal screen is fitted.
All VALVE transformers are tested for safety isolation.
Voltage proof from winding to frame is tested at 4000 Volts RMS or equivalent.
Voltage proof from winding to winding is tested at 4000 Volts RMS or equivalent.
Older type transformers such as rewinds meet the requirements in force at the time of original design.
We have no control over installation and use of our transformers.
We assume that anyone capable of choosing one of our transformers is competant to use it.

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[3.2] EMC Directive

Do you meet the EMC (ElectroMagnetic Compatability Directive)?

Directive EEC 89/336/EC

This does not apply directly to conventional transformers.
For Power Supplies and Inverters we create a technical file with a combination of Design notes, Simulations and Test results.
We use MIL-STD-461F, Def-Stan 49-411, RTCA DO160-D and MIL-STD704E as guidelines.

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[3.3] RoHS

Do you meet the RoHS (Restriction of Hazardous Substances)?

We comply with Directive EEC 2002/95/EC

Rewinds and replacement transformers for products made before July 2006 are exempt.
New products (including valve amplifiers to earlier designs are compliant).

We are colour coding all product shipped from June 2006.

Green dot or no marker indicates full compliance.
Red dot indicates non compliance (eg old stock or exempt).
Yellow dot indicates partial compliance or mixed materials.
Blue dot indicates full compliance with extra Tin Whisker mitigation processes.

Yellow dot product is usually only made for internal or prototype items.

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[3.4] WEEE Directive

Do you meet the WEEE (Waste Electrical and Electronic Equipment)?

Directive EEC 2002/96/EC

Most of our product is classed as a component used within a larger item. As such it will be recycled by the end manufacturer.
However any product returned to us will be dismantled and recycled.

Where possible reject and returned transformers are dismantled.
All useable parts are returned to stores (may be quarantined for internal use only).
Scrap copper and iron is sold to our local scrap dealer.

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[3.5] ISO 9000 / 9001

Are you approved to ISO9000?

Yes to ISO9001:2001 by QMS International PLC - at the first attempt.
We have been audited succesfully to the later vaersion - ISO9001:2008.

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[3.6] Military and Professional

Can you work to Military and Professional Specifications?

We have supplied product and design services to most of the Avionics and similar companies.
Call us for more details.

Some relevants specifications are:

We have been assessed to ISO9001:2008 sucessfully.

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[3.7] REACH Directive

Do you meet the REACH regulations?

Most chemicals that we use are in relatively small amounts.
These do not require declaring to REACH authorities.

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[4] Website Technical Notes

[4.1] General Website Notes

Some of your products seem to have been removed from the website. Why?

We recently restructured our website.
It was not possible to upgrade all our datasheets at once.
We can still supply all previous products.

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[4.2] Cookies

Do you use cookies?

We no longer use Cookies.
Note that you will still require to enable 'Java' on our Price Calculator Page.

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[4.3] Viruses and Spyware

Do you Virus Check E-Mails?

We use Norton AntiVirus to check all E-Mails in and out.
This is updated each time we go online.
We also have Spybot S & D and Malwarebytes.
All our data is scanned prior to upload onto our server.

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[4.4] SPAM

How do you deal with SPAM?

Our Server marks most of the SPAM emails for use.
These are deleted un-opened.
Other Emails that appear to be SPAM are also deleted un-opened.
Any supplier who sends us several Emails (particularly large ones) is deleted from our approved suppliers list. Any Email without a valid 'To' address is deleted.
Any Email with a dodgy title is deleted.

We never send SPAM out.
All our emails are sent to one address.
We also 'cc' these for internal use and to confirm successful transmission.

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[4.5] JavaScript

I can't access your JavaScript calculator pages.

You may have JavaScript processor disabled.

Try one of the following:

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[4.6] Website Design

How is the Site created?

All top level pages are coded in HTML4 using Microsoft Notepad.
Data sheets are generally coded using home grown Visual Basic 5 Active-X modules which create HTML4 pages.
Calculating pages (eg Price Calculator) are coded using JavaScript and HTML4.

A standard Style sheet is used to control the appearence of all pages.

Images are compressed to reduce download time.

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[4.7] Feedback and User Forum

Is there a feedback system or a means for contacting other customers?

There will be a User Forum in the future - as soon as we have spare software time.
This will be powered by Snitz Forums (see 'forum.snitz.com' for details on how it works).

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[4.8] Phorm

Do you use Phorm to get or use information on visited sites?

We do not subscribe to Phorm - We disagree with it's principles of privacy invasion.

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[5] Communications

[5.1] Can't contact

Why can't I get a reply to Telephone, Emails or Voice Mail?

Leave a message on voicemail or email the sales office.
It may be several days before we can deal with your enquiry.

Telephone sales line is normally available between 11am and 4:30pm Mondays to Thursdays.
Voicemail, email or Fax during staff holidays.
Voicemail messages are often difficult to understand due to background noise etc.
Voicemail users should leave a telephone number that they can be contacted on, and the times that they will be available.

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[5.2] Emails

How do we handle Emails?

We have several Email accounts.
The main ones are shown on our Index page.
This allows us to monitor the source of the enquiry.
We also have a Email account for design department follow up correspondance.
Pick the most appropriate address to send to. We will route to the correct person.
It is not necessary to send to all addresses. If you do you may get several conflicting replies.

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[6] Company Information

[6.1] Supplier ?

How do we become a supplier to VVT Ltd?

Do not send us sales literature or SPAM.
If you feel that you have a service or supply that would be useful to us, send us a SMALL text email with your website address.
We automatically delete anyone who SPAMs us from our potential suppliers list.

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[6.2] Where?

Where do you make your transformers?

All our transformers are designed, manufactured and tested on the Isle of Wight.

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[6.3] Isle of Wight

Is the Isle of Wight part of the UK?

The Isle of wight is a county in England UK.
It is about 2 miles off the coast of southern England.
Standard UK trading rules apply.
Company is Registered in England.

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[6.4] Contact and address

Where do I get contacts and accounts office information?

From our Index page (home page)

Link to Home Page and Contact Details
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[6.4] Variable Voltage Technology

Why are you called Variable Voltage Technology Ltd?

When we first started trading (in 1987) we specialised in Electronic Bench Variable Power Supplies.
At that time we bought in our transformers.
Eventually we changed suppliers and finally took over our transformer supplier.
We have concentrated since then on supplying transformers into a wide range of markets.
We have never made Variable Voltage Transformers (eg Variacs) despite our name.
We do design and make specialist Electronic Power Supplies (including Variable Voltage) to order.

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[7] Terms and conditions

[7.1] Warranty

Do you guarantee your transformers?

All our products are guaranteed for normal operation for one year.
As these are generally fitted by the customer we can take no responsibility for any injury or consequential damage occured.

If you have any problems with our products let us know as soon as possible so that we can resolve the issue.
We will replace, redesign or refund as agreed.

We operate a 'FRACAS' database for 'Fault Recording And Corrective Action System' at all levels of our business.
You will be allocated a FRACAS code (eg X12345) for a particular problem.

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[7.2] Damaged in transit

Damaged in Transit?

Call us IMMEDIATELY.
We will discuss repair and or replacement under warranty.
Please keep any packing and Carrier information.

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[7.3] Trading Rules

Simplified Terms and conditions of trading.

We reserve the right to cancel an order due to payment problems or supply problems.

All orders must be paid for at the time of ordering unless a trading account has been set up.
Credit cards will be transacted when product has been tested.
Cheques will be presented when product has been tested.
Rewinds will be invoiced as soon as feasability has been confirmed.

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[7.4] Invoices

Invoices.

Invoices are generated where appropriate or on request.
VAT is identified where appropriate and is charged at the current UK rate at the time of delivery.
Most standard product has VAT included at the current rate.

Invoices must be paid with 30 days of the invoice for single orders.
For monthly accounts Balances must be paid within 7 days of statements.

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[7.5] Overdue Accounts

Overdue Accounts

Charges may be payable on overdue outstanding accounts.

These charges are based on the concept that you are borrowing money from us instead of a Bank.
Therefore we charge as if we were a bank.

Charges are our discretion and may include any or all of the following:

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[7.6] Design Changes Policy

Design changes and Alternative Parts.

We reserve the right to change to design of any product without warning.

This may be due to Material availability, Plant breakdown, Process problems or any other cause.
Where possible we will notify you.
If the changes are unacceptable to you, you may cancel the order without charge.
We will not accept any costs as a result of such changes.

[7.7] Design Changes Policy

Inability to supply.

We reserve the right to remove product or cancel orders if we are unable to supply a previously agreed order.
This may be due to Material availability, Plant breakdown, Process problems or any other cause.

This may happen at any time from enquiry to Delivery.

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© 2009 Variable Voltage Technology Ltd. Data Sheet Number DCW13271.