Eumig 800 HQS amplifier problem and solution

[Brian Fretwell]

I wonder if it was re-branded as a 812 for sales from a particular retailer. I'm sure some sound projectors in the Dixons Prinz range were re-badged Bolex ones

[Erik Snel]

yes that is very much a posibility, there are machines (601 and 801) made for Willoughby Peerless. C11 camera was made especially for a warehouse. indeed Prinz for Dixons were Revue's wich were eumig's with different housing parts, silent and sound alike. I believe the 2 silver grey projectors (Mark 608D and S812) were sold in Germany and Italy, at least thats where i find the adverts are coming from. i dont know it its from a particular warehouse butit could be.

[Phil Murat]

As Paul Browning mentionned on post above, measuring Capacitors ESR is a very good thing to have an idea of capacitors performances and health:
ESR means Equivalent Series Resistance. To make simple , bigger is capacitor , lower is ESR.
Exemple : A 4700µf Cap can show a good ESR around 0,02 Ohms, however, a 100µF Cap (Electrolitic too) can show a good ESR around 1 Ohms.

But a 4700µF Cap showing a 1 Ohms ESR (or higher) is poor and will fail certainly soon......

There are number of small devices on WEB to measure ESR for few money and easy to use.
Some capacitors are sold under label "Low ESR" , often times the are rated up to 105°C : There are made for "High Frequency current" (Modern Power Supplies , etc....)
Do not use ordinary caps (poor ESR and 85°C Temp limit) on Modern Power Supplies as they overheat and fail early.

Here is a guide chart to give a general idea :




ESR is :
- Frequency-dependent
- Temperature-dependent
- Changes as components age

It is usually only an important consideration in selecting Electrolytic capacitors.

ESR values also depend on Capacitors technology (Electrochimical, Tentalum, Polyester, etc.....)

[Joseph Banfield]

That amp looks like the same one that is used in the Bolex SM 80 (Eumig in disguise) but not marked as having HQS sound though.

[Lee Mannering]

Eric I still have my 807D purchased new in 1972 Christmas and it still works perfectly of course having been loved and treasured along with all my Eumig machines collected over 50 years, the pinnacle being my HID 860 Super Lux 😎

[Erik Snel]

Well Joseph that is correct, bolex did not use the HQS term. i have both a bolex sp8E and sp8 special, both have the hqs amplifier but not the designation.

also revue used the hqs amp and did not have this designation but there is a simple way of regognizing wich amp it has. when you look at the front and the backcover is only 6 cm then its not hqs. if the cover is 7,5 cm it is HQS. when you dont have a ruler with you you can see the space between the coolant grilles and backside is either small or wider.

@Lee thats very nice, i am way too young to have ever seen these machines new in the shops. I saw your 860 pictures in the other thread, very nice job!

[Joseph Banfield]

Erik, thanks for the confirmation on the amp in my Bolex SM80 being HQS amp. It does produce some booming bass, unlike my other Eumig machine that do not...just loud. Unfortunately my Bolex SM80 also has nasty film chatter in the sound on loud passages that becomes obvious when the sound is fed to an external amp or speaker.