Anyone aware of a Decca FFR25 amplifier…???

[Valvepower]

Hello,

This is a total long shot but is anyone aware of a Decca FFR25 amplifier. This would date back to the late 1950s.

I’ve trawled a few rabbit holes online (tried FFRR25 as well), Audio! Audio! Some Hi-fi year books and Pauls Service sheet DVD but to no avail.

The reason I ask… The Decca FFR25 gets mentioned in the chapter on amplifiers in the Second edition of the 1958 book High-Fidelity Sound Reproduction book by E. Molloy. The chapter on amplifiers was written by George W. Tillett, who worked for Decca Radio and Television at the time of writing. Not sure if later editions of the book mention the FFR25 though.

The driver circuit used as an example in the book is essentially the Mullard 5-20 circuit albeit with some diffing values and the Decola console and stereo separates used the Mullard 5-20 circuit in the power amplifier.

This had me thinking, did the FFR25 go on to become the later ‘EL34’ Decola console and stereo separates?

Scan of relevant pages of the book with FFR25 highlighted.

It might be blindly obvious; however, I can’t find anything.

Thanks in advance for any help.

Regards
Terry

[Edward Huggins]

This FRR ("Full Frequency Range") 25 model looks like one of the later valve amplifier developments by Decca, but was it ever brought into production? You may need to compare the circuit with the that of 1958 DECOLA.

[steve ss]

Ok.

This may be worth a look if you have not come across it. (see link)

Link:


https://www.hifido.co.jp/sold/08-360...-00.html?LNG=E



enjoy Steve ss.

[Valvepower]

Thanks for the replies.

Edward is thinking the same way as me and the FFR25 was a development project name and didn’t go into production using the FFR25 name - I’m kind of thinking eventually became the Decola separates?

Steve… good link to some cracking photos of a Decola preamp… Oh well, that would have been an ideal purchase as I only have the power amplifier and a preamplifier would be useful.

Regards
Terry

[Robint 47]

Terry
After working for Decca Radio and TV service division in Bridgnorth for many years i have never come across this amp, the only valve amp that i know is of course the Stereo Decola seperates there was a later amp the TSA33 but all transistor.
What i am wodering is with the advent of the ffrr system in 1945 and Decca being responsible for issuing for the first time in Europe the long playing record in 1950, arapid rethink of reproducing equipment was needed. This makes me wonder if the Decca record company being a seperate ident in the group, set to and designed their own amp possbly for studio use or demonstration with a frequncy response able to cope with the latest spec available they had built as far as i know some of their own recording equip so an amp with 20 watts out call it the ffr20.
R

[steve ss]

Ok.

Well it may not be "blindingly obvious" but may be close!

I think the Decola power amp and FFR25 are one and the same.

If I remember correctly the Decola amp was near triode ultra linear
or triode configured similar to the A10 Mk11 Armstrong amplifier
giving 12.5 watts/channel approx. (depending if you put your finger
on the scale when no one was looking)!
So 12.5 watts X 2 =25 watts!

Er FFR25!

Around 1958 every one was doing it Avantic/Beam Echo D35 Audiomaster A11 Armstrong A10 Decca Decola separates /console etc.
all Mullard5-20's variants in one form or another so it's not all together
surprising Decca went down the same path!

ie Excellent performance/Specs.and low R&D cost (All the heavy lifting done by Mullard) a winning combination!

So I thought I would include some Decola power amp pics (a nice looking example) for the "train spotters".


enjoy Steve ss.

[Robert Gribnau]

About the schematic of part of the Decca FFR25 as attached to post #1: Should there not be a connection between the cathode and the point where the capacitor marked "25" and the 0.05 uF capacitor connect? And would the values of the anode resistors of the ECC83 be correct? The value of 390K seems unusually high to me.

Attached is a schematic of a "Decola power amplifier" that I found on this site:

https://blog.goo.ne.jp/kobmina/e/2d4...ca2eae10bb96b1

The values in the attached schematic differ from the values in the schematic of the FFR25 as attached in post #1 though. This amplifier also differs in 'looks' from the pictures of the Decola in post #6.

[Valvepower]

Hello,

Thanks for all the replies - it’s really appreciated.

As I said in the OP I noticed some irregularities and such like in the circuit in the book, however I just put it down to just being an example circuit.

As regards the possible 25 watts and the Decola 12-15 watts I figure if one was to configure the triode connected Decola as UL (with the correct output transformer!) you would get roughly 25 watts.

I figure we’ll never know what it was and what did eventually happen to the FFR25 - if anything. I know speaking to a friend the studio world and he said Decca made custom/specialist gear.

Terry