Hi - I've come across an ad. for a hi-fi amp based on 6U1 and 6F1. On AliExpress. Looking up equivalents, suitable ones seem to be ECH81 for 6U1 but can't find one for 6F1 (shoot me down if I'm wrong...).
Has anyone got a circuit diagram for such an amp please? It's more out of curiosity as I guess wattage won't be very high at all, depite the phenomional claims in the ad.
Many thanks in advance.
Has anyone got a circuit diagram for such an amp please? It's more out of curiosity as I guess wattage won't be very high at all, depite the phenomional claims in the ad.
Many thanks in advance.
If the amp is based on a ECF80 type of valve it can't be worth bothering with. The ECF80 is a small signal triode/pentode, the pentode section with a power rating of 1.7w. They were used extensively in old valve Telequipment scopes.
Great forum ID BTW, I have a pair of Mission 720 speakers, some of the best speakers Mission built back in the day.
Great forum ID BTW, I have a pair of Mission 720 speakers, some of the best speakers Mission built back in the day.
Were the Mission 720 speakers, one of the models that put the Tweeter Below the Woofer?
I remember a very good sounding Mission speaker that used the inverted tweeter and woofer configuration.
I remember a very good sounding Mission speaker that used the inverted tweeter and woofer configuration.
That amplifier is hybrid , IC or transistor output power stage .
Of course they forgot to specify this 🙂
Of course they forgot to specify this 🙂
Caveat Emptor.
Marketing and Sales: Sell what sells (even if you have to hide the whole truth and the ugly truth)?
If it sounds too true to be good, it probably is.
Marketing and Sales: Sell what sells (even if you have to hide the whole truth and the ugly truth)?
If it sounds too true to be good, it probably is.
Hi - They are a 3-way driver system, 1" SEAS tweeter at the top, 4.25" Peerless mid in the middle and 10" Peerless bass at the bottom.
Great speakers - I have mine from new in 1979, and refurbished mid and bass a few years ago. Pictures on diyAudio under my name in another forum.
Thanks for the info. I've had my Mission 720 speakers from new in 1979. Refurbished mid and bass a few years ago. Fantastic sounding.
Indeed... no mention of that at all. Are you looking at the same amp that I looked at? I was just curious as never seen that valve combination in audio amps.
That's the ones, Seas H109 (if I remember right), Peerless SKO40 mids, and Peerless 10" woofer. I got mine in a totally wrecked condition after someone had "partied" them, burnt out tweeter, burnt out mids and woofer with the surrounds de-graded. I also have the 730's which were Mission's top of the range but doubt i'll ever get them working as the Celestion tweeter and mid are missing, all that remains of the drivers are the KO40's and woofers both need re-foaming which is hard to get for the woofers.
Back to the amp, a hybrid would explain things.
Last edited:
Original tweeters were Seas H107 (non-ferro fluid) whereas later versions used Seas H211 (with ferro-fluid). My 720 speakers have H107.
I restored a pair of Mission 730 MkII which were behemoth units and dwarfed the 720 model. The MkII were 3-way, again with the H107/211 tweeter and Peerless K040-MRF (Peerless 821385) 4.25" mid but a different 10" bass driver to 720. I seem to remember they were still Peerless, but not the same as the 720 Peerless 835231. The units I restored were missing bass drivers. I managed to get a pair of knackered ones from France but, after months of searching, the only foams I could get were from Australia! They restored beautifully and I did my duty and passed them on to another vintage Mission lover.
I suspect from your description you have the 730 Mk1 which had an additional tweeter, making 4 drivers in total.
I currently have another pair of 720 which are missing KO40 mids so if you were looking to part with yours I'd be very interested 🙂
I restored a pair of Mission 730 MkII which were behemoth units and dwarfed the 720 model. The MkII were 3-way, again with the H107/211 tweeter and Peerless K040-MRF (Peerless 821385) 4.25" mid but a different 10" bass driver to 720. I seem to remember they were still Peerless, but not the same as the 720 Peerless 835231. The units I restored were missing bass drivers. I managed to get a pair of knackered ones from France but, after months of searching, the only foams I could get were from Australia! They restored beautifully and I did my duty and passed them on to another vintage Mission lover.
I suspect from your description you have the 730 Mk1 which had an additional tweeter, making 4 drivers in total.
I currently have another pair of 720 which are missing KO40 mids so if you were looking to part with yours I'd be very interested 🙂
Last edited: