Anyone heard a Leak 70 ss amp ?

[ashok]

I briefly had a Leak 70 solid state amp at home 'many' years ago with a pair of Wharfedale Dovedale speakers ( built from a kit ) . Source was vinyl of course.
I remember it having tremendous bass slam which I don't find in many systems nowadays. Some do of course.
I vaguely remember a vinyl album "Silver Convention " though I don't recall if that had bass slam !

Does anyone who was not still in dispersed molecular form those days remember anything about this sort of a system? It would be interesting to hear from them. For those whose molecules coelesed later on never mind !

[markinuk]

Hi,

Possibly the slam you heard had as much to do with the Wharfedale Dovedales. IIRC, they had 12-inch main drivers (not so often seen these days); even the budget Wharfedales I owned (my first speakers) used 8-inch drivers - well above average by modern standards.

All these speakers were infinite baffle, i.e. closed box, designs of course. The bass reflex systems most of us probably own were a rarity back then.

Mark

[poynton]

If the speakers were Dovedale 3s, then yes it could be the speakers.
They are superb.!

I had a pair some time ago which I drove with Quad 11s. I gave them to a friend as a wedding present 16 years ago - he still has them and won't give them back.

As to the Leak 70 amp, it was very well regarded in its time - nothing special in terms of present day technology though.

Andy

[brianco]

Back in the 1960s in Ireland where I lived at the time the local market town cinema was owned by the local garage owner/mechanic!

He was a hi-fi nut. He used the smaller solid state LEAK 30 in the cinema for all non-soundtrack music.......it was beyond belief! but he was using a full cinema Western Electrics horn cinema speaker system. Anything could drive that: I took my Garrard 301, SME + SPU in there along with my Radford amps. Now that was something which really made music with those big horns.

The cinema has gone and the horns were junked in the 70s.

My memory of the Stereo 30 + Stereo 70 in domestic use was that they were thin and shrill at the top. I cannot remember what speakers were used.

[ashok]

Yes Mark those were Dovedale 3's. I put this kit together for a friend who still has them. However he has moved to a different city and so I can't get back to them easily.
I remember the woofer had a VERY stiff suspension. You couldn't move the cone by pushing it with your fingers like you can with most woofers nowadays. It appeared 'stuck'. However it had a very low Fs and was used in a sealed box.
I've been looking high and low for that 12 inch driver to test it and get its TS parameters. It really intrigues me.
I will get my chance sometime at my friends place I guess. I am not sure if he will let me dismantle it again.

Andy, it might be interesting to actually hear the Leak 70 on a modern speaker system today. Spec wise it might not be anything great. But then specs do not tell the whole story. The Leak 70 circuit is up on the web.

Brianco,
Your memory of the sound could have been also due to the source or the speakers. Do you still have access to the Leak 70 ?

Cheers.

[ashok]

The power amplifier circuit is attached. It's a single supply amp.
Current feedback circuit and with a pnp at the input to get the best noise performance possible ?

What does R49 (33K) connecting the supply to the bottom 2N3055 do ?
This circuit can be refined quite a bit. I'm playing around with the circuit right now . Getting some interesting results. Wonder if the sim is correct.
I need a good Spice model of the TIP142/147 .
Cheers

[mjf]

hello.
for many years i was listening radio-music (and sometimes cd) with my leak delta 75 receiver.the sound is present in the mid's and bright in the treble,can not say there is much punch in the bass.but i like that old apparatus.
there is the schematic of the main amplifier...........amazingly it has no emitter res in the output stage.
and in the preamp the volume control has two taps that create some kind of loudness.
greetings..............