Colin Wonfor SECA Amp + Lampizator open baffle speakers - Sovereign / James Coltart

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30-01-2022, 18:02
lpcollier

Colin Wonfor SECA Amp + Lampizator open baffle speakers - Sovereign / James Coltart
For sale as one lot, circa £1500:
- Colin Wonfor TOCA SECA - Single Ended Class A Amplifier dual mono 50W?
- Loudspeaker DIY design based on Lampizator P17 Endorphine open baffle
- "Mother Trucker" DIY balanced power supply - needs repair/development
- Collection of cables and spares
Those who have been on this forum for a while will remember James Coltart, otherwise known as Sovereign. He sadly passed away in 2017 leaving his widow with a listening room full of experimental, custom and DIY HiFi equipment. ( https://theartofsound.net/forum/memb...7321-Sovereign)

To raise money for the family and to honour James' memory I spent 2018 and 2019 repairing, testing and selling the majority his collection to forum members and via eBay. COVID then hit and I had to shelve the project until now (I'm a dual-trained engineer and medical doctor and the latter took priority for obvious reasons).  I've now had time to properly look at the centrepiece of James' collection and I'm now offering the amplifier and speakers for sale, together with a small collection of other parts and accessories.

Speakers

The speakers are based on the Lampizator P17 open baffle design. James had left them in the process of experimenting with different drivers and so the tweeters had been removed, and the crossovers were wired in a prototype point-point design. I've refitted the HF drivers and reverse engineered the crossover design as he left it and implemented it on tag board. The crossover design is "wrong" based on the P-17 page (http://lampizator.eu/speakers/projec...20Kitchen.html) but I've left it as I found it!

Some of the rubber washers are missing from the speaker mountings. There was a tear in the paper cone on one HF driver, which I have repaird, and there is also slight damage to the surround of one bass driver as pictured, otherwise all the drivers look fine. The cabinets are functional with castors on the bottom, and would make a great project for someone who enjoys cabinet finishing to upgrade the appearance.

Amplifier

The amplifier is a Colin Wonfor TOCA SECA Single Ended Class A, assembled by James with input from Colin. It's a dual mono design with the toroidal transformers stacked on top of each other. The heatsinks are huge. I believe that the circuit was modified with advice from Colin to increase the power output - I seem to remember 50W but this may not be correct. I had to do a bit of repair work to the incoming mains supply as I think this was hardwired at one point, but nothing else has been modified.

Performance

What you want to know is, how does it sound? To my ears, absolutely fantastic. I've tested it with Amazon Music HD on a Macbook Pro M1 with the headphone output running straight into the amplifier and everything wired up with budget interconnects. Despite the less than ideal setup, I've spent a very enjoyable afternoon listening to Kind of Blue and heard detail from the trumpets that I've never appreciated before. This system isn't really suitable for serious rock music, but the more jangly guitars of Sultans of Swing sound fantastic. My personal go-to test track is Hugh Masekela's Stimela on the live album Hope - this system blew my socks off with huge dynamics and again detail on the trumpets and vocals.

Other bits
Included in this sale is a collection of interconnects as pictured, some spare HF drivers, and a budget shelf unit. I'm also throwing in a large balanced power supply that appears to be faulty - it trips the RCD in my consumer unit when I plug it in.

The amp and speakers are available to audition in Maidstone, Kent. Anyone with a serious intention to buy is invited to come with their own source and preamp and spend as long as you like listening. I really only want to sell this as a complete lot as I'm very much at the end of my time and energy to work on this.

As far as pricing goes, anyone who's built their own system will appreciate the medium four figure sum that's gone into building this system over a number of years. It is complete, working and ready to plug into a suitable preamp right away. There's also a chance for someone with the relevant experience to build on this system to improve it sonically and aesthetically. As the forum requires a price, I'm going to start with circa £1500, let's talk...

Photos

Dropbox link to 30 high resolution photos: https://www.dropbox.com/sh/lnkhcjfqk...rdgdNf66a?dl=0

http://brighterlouder.co.uk/wp-conte...5438-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5440-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5467-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5454-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5470-copy.jpeg
30-01-2022, 18:32
bumpy

Aside from James I may be the only other person on here using the P17 open baffles, so would like to offer myself as a contact point if anyone needs additional info. I recognise the Saba Greencone mid and tweeter but can’t make out the 15inch bass driver. GLWTS
31-01-2022, 10:18
lpcollier

Thanks, I would really appreciate your input. There's a link in the post to hi-res photos on Dropbox, you can see the rear of the bass drivers on there. I don't think they're the Altec Lansing drivers mentioned on the P17 page, but appear to be a capable alternative - certainly based on my listening test.
31-01-2022, 13:52
bumpy

Emmm
Unless I'm missing something, I cant see a picture of the rear of the bass driver :(
31-01-2022, 16:28
lpcollier

Quote:

Originally Posted by bumpy

Emmm
Unless I'm missing something, I cant see a picture of the rear of the bass driver :(

Totally my bad, sorry, it didn't upload for some reason. It's on there now.
31-01-2022, 18:24
Colin Wonfor
Quote:
Originally Posted by lpcollier

For sale as one lot, circa £1500:

Colin Wonfor TOCA SECA - Single Ended Class A Amplifier dual mono 50W?
Loudspeaker DIY design based on Lampizator P17 Endorphine open baffle
"Mother Trucker" DIY balanced power supply - needs repair/development
Collection of cables and spares

Those who have been on this forum for a while will remember James Coltart, otherwise known as Sovereign. He sadly passed away in 2017 leaving his widow with a listening room full of experimental, custom and DIY HiFi equipment. ( https://theartofsound.net/forum/memb...7321-Sovereign)

To raise money for the family and to honour James' memory I spent 2018 and 2019 repairing, testing and selling the majority his collection to forum members and via eBay. COVID then hit and I had to shelve the project until now (I'm a dual-trained engineer and medical doctor and the latter took priority for obvious reasons).  I've now had time to properly look at the centrepiece of James' collection and I'm now offering the amplifier and speakers for sale, together with a small collection of other parts and accessories.

Speakers

The speakers are based on the Lampizator P17 open baffle design. James had left them in the process of experimenting with different drivers and so the tweeters had been removed, and the crossovers were wired in a prototype point-point design. I've refitted the HF drivers and reverse engineered the crossover design as he left it and implemented it on tag board. The crossover design is "wrong" based on the P-17 page (http://lampizator.eu/speakers/projec...20Kitchen.html) but I've left it as I found it!

Some of the rubber washers are missing from the speaker mountings. There was a tear in the paper cone on one HF driver, which I have repaird, and there is also slight damage to the surround of one bass driver as pictured, otherwise all the drivers look fine. The cabinets are functional with castors on the bottom, and would make a great project for someone who enjoys cabinet finishing to upgrade the appearance.

Amplifier

The amplifier is a Colin Wonfor TOCA SECA Single Ended Class A, assembled by James with input from Colin. It's a dual mono design with the toroidal transformers stacked on top of each other. The heatsinks are huge. I believe that the circuit was modified with advice from Colin to increase the power output - I seem to remember 50W but this may not be correct. I had to do a bit of repair work to the incoming mains supply as I think this was hardwired at one point, but nothing else has been modified.

Performance

What you want to know is, how does it sound? To my ears, absolutely fantastic. I've tested it with Amazon Music HD on a Macbook Pro M1 with the headphone output running straight into the amplifier and everything wired up with budget interconnects. Despite the less than ideal setup, I've spent a very enjoyable afternoon listening to Kind of Blue and heard detail from the trumpets that I've never appreciated before. This system isn't really suitable for serious rock music, but the more jangly guitars of Sultans of Swing sound fantastic. My personal go-to test track is Hugh Masekela's Stimela on the live album Hope - this system blew my socks off with huge dynamics and again detail on the trumpets and vocals.

Other bits
Included in this sale is a collection of interconnects as pictured, some spare HF drivers, and a budget shelf unit. I'm also throwing in a large balanced power supply that appears to be faulty - it trips the RCD in my consumer unit when I plug it in.

The amp and speakers are available to audition in Maidstone, Kent. Anyone with a serious intention to buy is invited to come with their own source and preamp and spend as long as you like listening. I really only want to sell this as a complete lot as I'm very much at the end of my time and energy to work on this.

As far as pricing goes, anyone who's built their own system will appreciate the medium four figure sum that's gone into building this system over a number of years. It is complete, working and ready to plug into a suitable preamp right away. There's also a chance for someone with the relevant experience to build on this system to improve it sonically and aesthetically. As the forum requires a price, I'm going to start with circa £1500, let's talk...

Photos

Dropbox link to 30 high resolution photos: https://www.dropbox.com/sh/lnkhcjfqk...rdgdNf66a?dl=0

http://brighterlouder.co.uk/wp-conte...5438-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5440-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5467-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5454-copy.jpeg

http://brighterlouder.co.uk/wp-conte...5470-copy.jpeg
The 50W SECA are unique the only pair made by anybody except me. The Parts alone cost more than £1500 and will be most happy to supply the circuits to the new owners.

I miss James he was great friend.

Best Colin Wonfor
31-01-2022, 19:17
bumpy

OK, those bass drivers are ARO 9408 made by Tesla in Czechoslovakia around the mid to late 50s.

So there is a full compliment of vintage drivers with the common traits of paper cones, alnico magnets and high sensitivity. This will make for a well voiced, coherent sonic output over the entire frequency range. There in no problem with foam support rot which bedevils later old drivers, as in the 50's the drivers were made to last almost forever.

The sound will be 'relaxed' detailed and beautiful, particularly when married up to valves.

These speakers are very much a DIY project and from a wonderful start, can be considered a work in progress, with the ability to improve on every element. All parts are available still, and if you are like me, much of the fun is in being able to understand and improve them if you wish whilst being captivated at every point.

They work fantastically well with most genres of music except heavy rock head bashing. In particular Jazz, Irish, Country, 60s pop, Club Dance, Reggae and Dub music - this for me incudes Dire Straits, Leonard Cohen, the Shadows and Bob Marley.

Heavy Rock is compromised in OBs due to an indigenous lack of very low frequencies, but what there is in the bass is real and full of impact.

In summary a wonderful pair of speakers.
06-02-2022, 20:48
lpcollier

Thanks, I really appreciate your info on these speakers. I've had another look at the crossovers and decided to revert to the wiring as shown on the Lampizator project page, I think I either made a mistake in how I interpreted the point to point wiring that I inherited from James or maybe he was experimenting with different drivers and crossover configurations. It's now as detailed on the project page, including the recommended additional inductor. It sounds even smoother to me now and has lost some slight reediness that I heard in the upper midrange on the previous configuration that was complimentary to brass instruments but not so much for vocals, it's a bit more balanced as it is now.

If I don't get any interest from anyone to buy the whole lot then I'll put up a new post with the speakers and amp separately. I feel a bit more confident to do that now I've had info on the speakers from you and the amp from Colin. Maybe there's people out there who would buy them separately but don't have the money or need for the complete set. I'll leave it a couple more weeks before changing strategy. I like the idea of the system staying together as a legacy, but I'm more concerned to clear out my garage and boost Molly's bank balance at this point. I have had a couple of moments where I considered keeping this whole system, but I can't afford to pay Molly what it's worth right now and I don't want to hold onto it any longer now I've got it all working.
07-02-2022, 00:37
lpcollier

Update: the amp is sold, I will create a new post shortly for the speakers alone.
07-02-2022, 11:14
bumpy

Quote:

Originally Posted by lpcollier

Thanks, I really appreciate your info on these speakers. I've had another look at the crossovers and decided to revert to the wiring as shown on the Lampizator project page, I think I either made a mistake in how I interpreted the point to point wiring that I inherited from James or maybe he was experimenting with different drivers and crossover configurations. It's now as detailed on the project page, including the recommended additional inductor. It sounds even smoother to me now and has lost some slight reediness that I heard in the upper midrange on the previous configuration that was complimentary to brass instruments but not so much for vocals, it's a bit more balanced as it is now.

I think you're wise to put them back to original - its a good starting point for future owners. The original crossovers have served me well with only minor changes when I have changed drivers.

Those speakers can be driven with just about any amp. My 'lowest' is a 1.8watt. As the saying goes, "everyone should hear Open Baffles at least once in their life."

I did, and never went back to boxes or horns.
10-02-2022, 10:52
Colin Wonfor

More info on "A Class" amps here :- https://seca.freeforums.net/
21-02-2022, 09:04
Colin Wonfor

Circuit diagram for this SECA can be found here, yes you do need to sign up.

https://seca.freeforums.net/thread/3...oject-circuits
28-02-2022, 23:47
topoxforddoc

Collected this today from Lee, as it was the first time I could get away. Lovely chat with Lee and I looked inside the paediatric air ambulance, which he provides medical cover for. Shame I didn't have time to have lunch with him today.
The amp is a real testament to James' work, as it looks beautifully built. It would put some "high end" amplifiers to shame. I managed to hook this up and it sounds fabulous - a real treat. Thank you to Lee and to Colin Wonfor, who has kindly sent me the circuit diagrams. I hope that the funds will help with James' widow and teenage daughter.