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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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5th Jun 2020, 6:51 pm | #1 |
Nonode
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30PL15 field output
Mazda produced 30PL13 and 30PL14 valves for field output, probably intended
for the later 110 degree sets. These are not pin compatible with PCL85/805 triode pentode, a standard on Thorn sets. Mazda 30PL15 is pin compatible but is a triode beam tetrode, although the mu is lower. What sets used it, and was it better than PCL805 ? |
5th Jun 2020, 8:02 pm | #2 |
Dekatron
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Re: 30PL15 field output
I have seen the 30PL15 in receivers I have serviced but very few and far between. I can't think of a single model that used it in new production.
I think it was launched around 1964 and by that time the leading set makers that used Mazda valves had been merged with makers that used Mullard valves. Murphy-Bush. Ultra-Thorn and Ekco-Pye. It was probably introduced too late to be taken up by setmakers. I believe the original PCL85 was introduced by Peto-Scott and The Philco Codenta of late 1960, early 1961.John |
5th Jun 2020, 8:46 pm | #3 |
Dekatron
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Re: 30PL15 field output
Just checked my B9A TV valves and discovered this 30PL15. 22/6d plus purchase tax! No wonder it was not very popular.
As far as reliability is concerned I would think it to be a first class valve if the 30PL1 the Mazda equivalent to the Mullard PCL83 is anything to go by. Regards, John. |
5th Jun 2020, 8:53 pm | #4 |
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Re: 30PL15 field output
Late production 30PL15s were made by Mullard having the internal appearance as the PCL85.
DFWB. |
5th Jun 2020, 9:32 pm | #5 |
Dekatron
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Re: 30PL15 field output
I've used 30PL15 to replace PCL85/805. I think my 11U is running with one at the moment.
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5th Jun 2020, 10:21 pm | #6 |
Nonode
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Re: 30PL15 field output
Hi!
Mazda triode–pentode valves were, in the experience I had with them in my servicing days, reliable and long–lasting, much better than than the Mullard equivalents – the 30PL1 triode/beam tetrode always gave a good account of itself in TV audio stages! For some peculiar reason, the PCL805/85 never gave anything like as much trouble in colour TV field T.B. circuits as it did in black and white sets, e.g. ITT hybrids, Körting, Saba, etc., and I never did work out just why this valve was so reliable in colour sets! I came across one or two cases of field collapse in colour sets with the PCL805/85 but it was never down to valve–failure, either D47f going o/c or s/c or a h.t. feed resistor o/c! Chris Williams
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5th Jun 2020, 11:09 pm | #7 |
Nonode
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Re: 30PL15 field output
Thanks all.
I'll find one for my 1400 (Ultra 6660 20") as the PCL805 is acting up. I remember replacing 3 PCL805s in 1500s in a week 40 years back. It was often worthwhile fitting the extended length B9A holder to save the PCB from heat damage. |
5th Jun 2020, 11:09 pm | #8 |
Dekatron
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Re: 30PL15 field output
Mazda produced some of the best valves ever manufactured but they had a small problem with any form of rectifier.
Their RF and audio valves were unsurpassed for quality but were restricted to a few loyal set makers that did their best to get over the rectifier problem. I think the PCL805/85 lasted well in colour receivers due to the very generous output transformers that were employed, [ITT/KB CVC5]. John. |
5th Jun 2020, 11:15 pm | #9 |
Nonode
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Re: 30PL15 field output
I agree. At a rally I picked up a carton of new Mazda PFL200s for £2. Nobody wanted
them as they had ten pins. |
6th Jun 2020, 6:49 am | #10 |
Nonode
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Re: 30PL15 field output
Hi!
One way set–makers like Ekco and Murphy got round Mazda's problems with TV rectifier valve quality was to go over to metal h.t. rectifier units – there were some very reliable replacements made – I think Automat ones were renowned for reliability – I never had many problems with stinky ones in my servicing career, only low h.t. due to deterioration of the selenium! (It did occur tho' – I remember P.T. reported the RSPCA once complaining of an unusual number of dog and cat cruelty cases on the 1950s shortly after commercial TV took off, and nobody ever twigged it was the metal h.t. rectifier in the telly that was the cause, because the stinky rectifier didn't always cause the width to go in – any competent TV engineer would know, but not the baffled set owners! They were equally puzzled from about 1961/1962 when said dog and cat mis–treatment cases suddenly dropped off sharply because owners were buying or renting new sets, and the BY100 silicon diode h.t. rectifier had arrived on the scene to put an end to the nonsense, once and for all.) Chris Williams
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6th Jun 2020, 9:35 am | #11 |
Dekatron
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Re: 30PL15 field output
Mazda were always ahead with valve design. The AC/PEN indirectly heated output pentode, the one with a nut and bolt inside, was a revelation when it made it's appearance in 1932.
During the mid 1960's they produced a range of frame grid tuner VHF tuner valves that would have been welcomed with open arms if they had been available in the late 1950's. These high gain tuner valves together with the 30PL15, Mazda's answer to the PCL85/805 were just too late for general use and with UHF just around the corner, were not taken up by the makers that were being reliably supplied by Mullard. Probably their 30L15 was the best known tuner valve exclusive to Mazda. It was not a frame grid valve but gave double the gain on Band 3 when fitted in place of the 30L1/PCC84 with just a slight adjustment to the tuner. Mazda very much liked tetrodes. Maybe there was a patent problem with the Philips Pentode. The 30PL1, 30FLI come to mind, in fact almost the complete range of output valves were described as tetrodes in their data lists. John. |
6th Jun 2020, 10:17 am | #12 |
Heptode
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Re: 30PL15 field output
I can remember when working for a RBM dealership in the very early 70s the PCL85/805 supplies became scare and we were often running very low, it was a troublesome valve and often had to be replaced in warranty. The Mazda rep suggested the 30PL15 as a replacement and we were impressed with the reliability making the higher cost justified?
John. |
6th Jun 2020, 10:20 am | #13 |
Dekatron
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Re: 30PL15 field output
A 30PL15 made by Mullard. As the attachments show it looks identical to the PCL85. This valve was made in 1976.
DFWB. |
6th Jun 2020, 12:50 pm | #14 |
Dekatron
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Re: 30PL15 field output
From the 1966 Mazda valves and teletubes booklet.
The characteristics of the 30PL14 and 30PL15 are identical. Just the pin connections are different. DFWB. |
6th Jun 2020, 12:59 pm | #15 |
Dekatron
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Re: 30PL15 field output
They did sort the problems out with the PCL85/805 and it did become quite a reliable valve.
I remember that period when they were hard to obtain. Mazda may done some business with the 30PL15 at this time. I remember obtaining some odd looking examples from Z&I Aero Services in London. They were very reliable but didn't look like Mullard or Mazda versions! I didn't think the PCL85/805 was actually manufactured by any other maker such as Cossor etc. Other than the big two, almost every other valve maker had thrown the towel in by the late 50's. Mazda must have been the only maker that made their own version of it. John. |
7th Jun 2020, 12:57 am | #16 |
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Re: 30PL15 field output
Philips manufactured several beam tetrodes, but they called them pentodes for marketing reasons. All line output valves, at least from the PL36 and PL81 onward, but possibly also the PCL85/PCL805 (early Philips PCL85 may have had a different internal design, late Philips PCL85 were early revisions of their PCL805).
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7th Jun 2020, 3:44 pm | #17 |
Octode
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Re: 30PL15 field output
Was there a Mazda version of the ECC85 and/or ECC88?
TimR
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7th Jun 2020, 4:26 pm | #18 |
Nonode
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Re: 30PL15 field output
According to data booklets, yes. They were competitors, although later on valves of
one make appeared in boxes of another. PCL85 and 805 and other types of high quality were also produced by Telefunken (although I do not know if these had UK distribution) I well remember we sold a lot of Pinnacle valves at one time, many were foreign made. |
7th Jun 2020, 5:12 pm | #19 |
Dekatron
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Re: 30PL15 field output
"Was there a Mazda version of the ECC85 and/or ECC88?" In the Mazda valve code system ECC85 was known as the 6L12. The ECC88 is not listed in the 1966 book
DFWB. |