What is the closest alternative to CV4002?
Hi All!
I'm new to this forum and valves in general, but this seems to be the place to ask valvey questions.
I have an old circuit that features a couple of CV4002 valves. It looks like 2 class A amplifiers in series acting as a preamplifier. I want to build it, hence need valves. I believe that the CV4002 is a military valve with wires rather than pins. If possible, I'd prefer pins so would need to look for an alternative.
I've read that it might be EF91 or M8083 kinda like. It's a bit confusing to a valvelar virgin. The thing is, I already have a circuit diagram with all the component values. I was hoping that just building it with a close alternative might be sufficient to get it to work. I don't have a great deal of analogue skill, and none with valves. I can use LTSpice though, but was hoping to avoid the hassle of installing valve models.
1. What would the closest electrical alternative be?
2. Would that alternative still require component redesign?
3. Is it all just easier to try to source CV4002s?
Thanks in advance.
Hi All!
I'm new to this forum and valves in general, but this seems to be the place to ask valvey questions.
I have an old circuit that features a couple of CV4002 valves. It looks like 2 class A amplifiers in series acting as a preamplifier. I want to build it, hence need valves. I believe that the CV4002 is a military valve with wires rather than pins. If possible, I'd prefer pins so would need to look for an alternative.
I've read that it might be EF91 or M8083 kinda like. It's a bit confusing to a valvelar virgin. The thing is, I already have a circuit diagram with all the component values. I was hoping that just building it with a close alternative might be sufficient to get it to work. I don't have a great deal of analogue skill, and none with valves. I can use LTSpice though, but was hoping to avoid the hassle of installing valve models.
1. What would the closest electrical alternative be?
2. Would that alternative still require component redesign?
3. Is it all just easier to try to source CV4002s?
Thanks in advance.
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CV4002 is just a EF91 with wire leads instead of pins, so any of the EF91 variants will work fine in your circuit.
EF91, CV4014, Z77, M8083, 6AM6, are all equivalent.
EF91, CV4014, Z77, M8083, 6AM6, are all equivalent.
Strictly speaking, it is a special quality version of the EF91 with wires instead of pins. CV4014, M8083, 6064 are the pinned versions but it is likely that any EF91 type would do unless you need low microphonics.
As a general rule, service valves in the CV4000 series were special quality - but exactly what sort of special quality will vary from type to type. Some will be extra robust to cope with vibration, others may have long life, or low grid current, or tightly controlled characteristics, or cope with long periods cutoff without suffering cathode interface problems.
As a general rule, service valves in the CV4000 series were special quality - but exactly what sort of special quality will vary from type to type. Some will be extra robust to cope with vibration, others may have long life, or low grid current, or tightly controlled characteristics, or cope with long periods cutoff without suffering cathode interface problems.
Thanks. When you say equivalent, do you mean identical? It's just that some times electronic components are more "equivalent" than others, and there is an order of substitution. If CV4002 is a military ruggedised valve, presumably that is reflected in thicker coils or supports. Might that not then also be reflected in the performance characteristics? I was hoping to avoid circuit amendment. I'd just plop them in.
You recommend just getting the cheapest from your list?
They are all equivalent in electrical characteristics i.e. the variation between them is similar to or less than the sample variation within one type. With valves there is no such thing as "identical". 'Equivalent' is the closest you will get, and almost all good valve circuits will be designed to cope.
These days you are likely to find that all EF91 equivalents are similar in price, apart from where 'Mullard' printed on the outside (irrespective of what is inside) boosts the price.
These days you are likely to find that all EF91 equivalents are similar in price, apart from where 'Mullard' printed on the outside (irrespective of what is inside) boosts the price.
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