Dulci stereo power amplifier - UK Vintage Radio Repair and Restoration Discussion Forum

GLENZ32 · 22nd Apr 2021, 12:14 pm

Hi guys, I have this Ducli single ended stereo power amplifier using an EZ80, and a single EF86 & EL84 per channel that I'm after a circuit diagram for, mostly complete by someone has been at it and there are components missing. It looks like a DPA10 but obviously isn't a mono amp

Image attached is what one looks like and mine has no identification model number. I'm guessing it's similar to a Mullard design from the era? Thanks in advance

ms660 · 22nd Apr 2021, 12:25 pm

Looks like an SP44:

http://www.hifiworks.co.uk/images_fullsize/dulci.jpg

http://www.hifiworks.co.uk/images_fullsize/dulci5.jpg

Lawrence.

GLENZ32 · 22nd Apr 2021, 12:30 pm

Hi Lawrence, yes that's the beast thanks for that useful info. I accidentally put this post in th e wrong forum and have contacted the moderator to ask that it be moved to the correct place

snowman_al · 22nd Apr 2021, 12:33 pm

SP44 or SP55.
Chassis on the SP44 is 6'' x 111/2'' x 51/2''
SP55 is 6'' x 111/2'' x 71/2''
SP44 at a guess.

DMcMahon · 22nd Apr 2021, 12:53 pm

I initially thought that it might be similar to the Mullard design listed in Post # 20 of this linked Thread but now see that this particular Mullard design uses ECL86's and a different rectifier valve.

https://www.google.com/url?client=in...kov1biG4wE-FOb

David

Edward Huggins · 22nd Apr 2021, 2:03 pm

The OP's photo under #1shows the correct control unit for this. The Stereo-8, a much more complex pre-amp shown in #2, was normally supplied wth the DPA10s. You will find that this version may be very close to the Mullard 3-3 design, as was the DPA10 to the 5-10. We had a Trade Account with DULCI. I can't quite remember how the EF86 was coupled to the EL84 though? Dulci used quite good components. Although the OPTX may loook a tad small, they are adequate for the job and better than many.

ms660 · 22nd Apr 2021, 4:15 pm

Quote:

Originally Posted by Edward Huggins

You will find that this version may be very close to the Mullard 3-3 design

Could well be so far as I can make out from this photo:

http://www.hifiworks.co.uk/images_fullsize/dulci6.jpg

Lawrence.

Restoration73 · 22nd Apr 2021, 6:33 pm

If the control unit shares the power unit, I think use of EZ81 is preferable.

GLENZ32 · 22nd Apr 2021, 11:28 pm

Thanks everyone for providing some more information on this, at least that image of that one underneath will give me a guide to go by

By all accounts it should be a nice little performer once up and running and will run my old Tannoys without a problem no doubt.

qualityten · 26th Apr 2021, 10:20 am

Some really good links here to the Mullard 44, including a schematic and complete assembly manual in Italian, but fairly easy to follow. https://audiokarma.org/forums/index....44-amp.879461/

22nd Apr 2021, 12:30 pm	#3
GLENZ32 Hexode Join Date: Apr 2008 Location: Wellington, New Zealand Posts: 289	Re: Dulci stereo power amplifier Hi Lawrence, yes that's the beast thanks for that useful info. I accidentally put this post in th e wrong forum and have contacted the moderator to ask that it be moved to the correct place __________________ Visit my Vintage TV & Radio Page - http://nzvintagetvradio.blogspot.com/

22nd Apr 2021, 12:33 pm	#4
snowman_al Octode Join Date: Dec 2018 Location: Llandeilo, West Wales, UK. Posts: 1,092	Re: Dulci stereo power amplifier SP44 or SP55. Chassis on the SP44 is 6'' x 111/2'' x 51/2'' SP55 is 6'' x 111/2'' x 71/2'' SP44 at a guess. __________________ Never Leave Well Enough Alone...

22nd Apr 2021, 12:53 pm	#5
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,600	Re: Dulci stereo power amplifier I initially thought that it might be similar to the Mullard design listed in Post # 20 of this linked Thread but now see that this particular Mullard design uses ECL86's and a different rectifier valve. https://www.google.com/url?client=in...kov1biG4wE-FOb David

22nd Apr 2021, 2:03 pm	#6
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,325	Re: Dulci stereo power amplifier The OP's photo under #1shows the correct control unit for this. The Stereo-8, a much more complex pre-amp shown in #2, was normally supplied wth the DPA10s. You will find that this version may be very close to the Mullard 3-3 design, as was the DPA10 to the 5-10. We had a Trade Account with DULCI. I can't quite remember how the EF86 was coupled to the EL84 though? Dulci used quite good components. Although the OPTX may loook a tad small, they are adequate for the job and better than many. __________________ Edward.

22nd Apr 2021, 6:33 pm	#8
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Dulci stereo power amplifier If the control unit shares the power unit, I think use of EZ81 is preferable.

22nd Apr 2021, 12:14 pm	#1
GLENZ32 Hexode Join Date: Apr 2008 Location: Wellington, New Zealand Posts: 289	Dulci stereo power amplifier Hi guys, I have this Ducli single ended stereo power amplifier using an EZ80, and a single EF86 & EL84 per channel that I'm after a circuit diagram for, mostly complete by someone has been at it and there are components missing. It looks like a DPA10 but obviously isn't a mono amp Image attached is what one looks like and mine has no identification model number. I'm guessing it's similar to a Mullard design from the era? Thanks in advance Attached Thumbnails __________________ Visit my Vintage TV & Radio Page - http://nzvintagetvradio.blogspot.com/

22nd Apr 2021, 12:25 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Dulci stereo power amplifier Looks like an SP44: http://www.hifiworks.co.uk/images_fullsize/dulci.jpg http://www.hifiworks.co.uk/images_fullsize/dulci5.jpg Lawrence.

22nd Apr 2021, 11:28 pm	#9
GLENZ32 Hexode Join Date: Apr 2008 Location: Wellington, New Zealand Posts: 289	Re: Dulci stereo power amplifier Thanks everyone for providing some more information on this, at least that image of that one underneath will give me a guide to go by By all accounts it should be a nice little performer once up and running and will run my old Tannoys without a problem no doubt. __________________ Visit my Vintage TV & Radio Page - http://nzvintagetvradio.blogspot.com/

26th Apr 2021, 10:20 am	#10
qualityten Octode Join Date: Feb 2009 Location: Wallasey, UK. Posts: 1,310	Re: Dulci stereo power amplifier Some really good links here to the Mullard 44, including a schematic and complete assembly manual in Italian, but fairly easy to follow. https://audiokarma.org/forums/index....44-amp.879461/