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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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9th Aug 2011, 2:20 pm | #1 |
Hexode
Join Date: Jan 2006
Location: Greater Manchester, UK.
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Is an EC88 half of an ECC88?
Simple question:
Is an EC88 half of an ECC88? From data sheets it looks that way or is there something I am missing? |
9th Aug 2011, 2:34 pm | #2 |
Rest in Peace
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Re: Is an EC88 half of an ECC88?
No, although there are some similarities. EC88 is the 6.3V version of PC88, intended for grounded-grid circuits in UHF TV tuners. ECC88 is for VHF cascode use. Both are high slope frame-grid valves.
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9th Aug 2011, 9:41 pm | #3 |
Hexode
Join Date: Jan 2006
Location: Greater Manchester, UK.
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Re: Is an EC88 half of an ECC88?
Right thanks got it.
So I need to stick to EC88 or PC88 the latter can be series/paralled and run at 7.6 volts @ 300mA. I had a feeling that they were different. |
10th Aug 2011, 8:54 pm | #4 |
Rest in Peace
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Re: Is an EC88 half of an ECC88?
No, PCC88 may be 7.6V at 300mA. PC88 is smaller heater voltage (about 4V?).
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10th Aug 2011, 10:23 pm | #5 |
Heptode
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Re: Is an EC88 half of an ECC88?
PC88 is 3.8V at 300mA. I use the EC86 in my phono preamp. It is quite similar to the EC88 but absolutely nothing like an ECC86! Ah the vagaries of valve nomenclature.
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11th Aug 2011, 12:37 pm | #6 |
Hexode
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Re: Is an EC88 half of an ECC88?
Dave
I think you misunderstood what I stated. If I put two EC88 in series then the volts required would be 7.6 and an increase in current to 600mA. If I then put a further two in parallel with that then the volts required would still be 7.6 volts. As I am thinking of building a MC phono pre pre amp which uses two EC88s per channel. As I can purchase a regulated supply which is variable from about 5 volts for supplying heaters for tube/valve amplifiers. If I used one of these that would put using EC88 in parallel outside the capabilities of the heater supply. Thus if I run them as series/parallel string I can set the heater volts on the supply to 7.6 volts which is within its working range. |
11th Aug 2011, 2:13 pm | #7 | |
Heptode
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Re: Is an EC88 half of an ECC88?
Quote:
The EC88 heater requires 6.3V @ 0.165A If you put two in series that's (2 x 6.3V) = 12.6V still at 0.165A If you put two in parallel that's 6.3V @ (2 x 0.165A) = 0.33A Or 4 valves in a series/parallel arrangement would be 12.6V @ 0.33A Alternatively, if you meant PC88, two in series would be 7.6V @ 0.3A Hope that helps, Andy
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11th Aug 2011, 2:28 pm | #8 |
Hexode
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Re: Is an EC88 half of an ECC88?
Yes your are quite right I had meant PC88.
It gets very confusing sometimes with the nomenclature. |
13th Aug 2011, 9:34 am | #9 |
Dekatron
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Re: Is an EC88 half of an ECC88?
Hi.
Perhaps a silly question, why are you using EC88's or PC88's as a phono amp?
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13th Aug 2011, 10:12 am | #10 |
Hexode
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Location: Greater Manchester, UK.
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Re: Is an EC88 half of an ECC88?
Why not?
If the circuit has been designed correctly then there should be no problem. Aside from which old tubes/valves are finding new functions and areas of operation i.e. new uses. There are after all no new tube designs in the classic sense and we have to work with what we have. One interesting point is those that are still being manufactured are not to such a high electro/mechanical tolerance as when Philips/Mullard were making them. Today's production tolerance is 10% as per data sheets which were modelled with 3-4% tolerance production tubes/valves. |
13th Aug 2011, 10:57 am | #11 |
Dekatron
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Re: Is an EC88 half of an ECC88?
I was just wondering about the choice, I remember them in the old UHF tuners and were awful lasting only a few months, no doubt fine for this application.
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Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member |
13th Aug 2011, 11:40 am | #12 |
Heptode
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Re: Is an EC88 half of an ECC88?
I've been using EC86s and EC88s in my phono preamp for several years now with no reliability problems.
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