UCD-700

dcyw · « **on:** 9 Dec 2005, 02:13 am »

Hi,
Will DIY Cable stock all necessary UCD-700 supplies? or better yet planning to build some 2 Ch amps? If going ahead will they be mono blocks or mono in a single chasis?
Time line?
Dave

Kevin Haskins · « **Reply #1 on:** 9 Dec 2005, 02:43 am »

Yes.... I have a couple on my desk right now.

We will certainly carry the parts, both the UCD700 & the power supply.

I'd like to do a dual mono UCD700 in our chassis but there just isn't enough room. Once you get two 800VA transformers you just don't have the space for two UCD700 power supplies and two UCD700 amps.

We can do a single supply and two UCD700s in our current chassis. That isn't a problem. The transformer would have to be special ordered though.

What I thought would make more sense would be to do a custom mono-block chassis. It would fit a UCD700 amp and UCD700 power supply, softstart and a single 800VA transformer with the correct secondaries. I can order the transformers with the correct secondaries but it requires a 50-piece order.

The chassis we would have to CAD up and get a quote from my chassis company. I've done enough work with them that I'm fairly certain it could be done in 4-5 weeks. We would do a 1/4" Aluminum front panel and have the UCD module mounted to some sort of extruded aluminum heat sink. The chassis would have good ventilation and black powder coating over a steel chassis. Steel is stronger for that hefty transformer and makes for a sturdier body. Aluminum looks better on the front and is critical for the heat sink.

I estimate retail price of a mono-block would be $1250 each for the UCD700AD. Do you think people would be interested? That is more power than most people need but it would be a fun exercise.

If we could get a commitment from ten people I'd start the project.

dcyw · « **Reply #2 on:** 9 Dec 2005, 03:29 am »

I have a pair of those big old inefficient full range panel speakers.
Highly reactive load, at certain frequency they can dip down to 0.5 Ohm.
I'm thinking the UCD-700 may be the ticket. They are efficient and stable with reactive load right? Either this or pick up a pair of used Bryston 7B ST. Other big amps are probably too expensive.

Kevin Haskins · « **Reply #3 on:** 9 Dec 2005, 04:25 am »

Quote from: dcyw

I have a pair of those big old inefficient full range panel speakers.
Highly reactive load, at certain frequency they can dip down to 0.5 Ohm.
I'm thinking the UCD-700 may be the ticket. They are efficient and stable with reactive load right? Either this or pick up a pair of used Bryston 7B ST. Other big amps are probably too expensive.

A half Ohm! I'd like to see the impedance curve. That may cause an issue with the short circuit protection. I'd have to ask Jan-Peter but I'd check your impedance curve first. That sounds like an unreasonable load and the designer of that speaker deserves some grief for making them such a beast to drive.

dcyw · « **Reply #4 on:** 9 Dec 2005, 04:56 am »

They don't sustain at 0.5 Ohm, the impedance just swing a bit wild.
norminal @ 4 Ohm.
My exsisting amp, a 200W Bryston 4B can drive them, but a bit out of breath.
I did blew up a pair of Carver 500W mono blocks and a Yamaha 150W stereo amp before!!!

dcyw · « **Reply #5 on:** 22 Dec 2005, 09:07 pm »

Hi,
I noticed that you are working on getting the Transformers for the Ucd 700 on the diyAudio Forum.
I'm still interested in the Ucd 700 amp. However, I like the idea of 2 monos with 2 transformers and power supplies in a single chasis with a single power cord. Would that require a single Soft Start or two? Will all this still fit in a 3U chasis?

Kevin Haskins · « **Reply #6 on:** 22 Dec 2005, 09:24 pm »

It won't fit in our standard 2U chassis... that is for sure. There is just too much to squeeze in there. Even if we had more height the two large 800VA transformers take up too much real estate.

I'm designing a mono-block chassis for the UCD700. Target dimensions are 13" deep, 3.5" tall and 7.5" wide.

speedcenter · « **Reply #7 on:** 23 Dec 2005, 10:15 pm »

Quote from: dcyw

I have a pair of those big old inefficient full range panel speakers.
Highly reactive load, at certain frequency they can dip down to 0.5 Ohm.
I'm thinking the UCD-700 may be the ticket. They are efficient and stable with reactive load right? Either this or pick up a pair of used Bryston 7B ST. Other big amps are probably too expensive.

Skip the Bryston - I have Odyssey Extreme Monos and they eat the Brystons for breakfast, but I'm building four UCD700s to replace those....

Using them on big maggies in a biamp setup. 1400w per channel HAS to be enough. at least my impedance doesn't go below 2.7ohm anywhere

The UCDs are not doubling power as the impedance drops - as far as I can tell, you won't get more than 6.5amps out of these things no matter what your impedance is.

Peter

speedcenter · « **Reply #8 on:** 23 Dec 2005, 10:22 pm »

Quote from: dcyw

Hi,
I noticed that you are working on getting the Transformers for the Ucd 700 on the diyAudio Forum.
I'm still interested in the Ucd 700 amp. However, I like the idea of 2 monos with 2 transformers and power supplies in a single chasis with a single power cord. Would that require a single Soft Start or two? Will all this still fit in a 3U chasis?

FWIW - here is the chassis I am ordering - one for each of my UCD700 monoblocks, since I have my amps right behind the speakers :

http://www.atiresearch-anodized.com/ATI-737U.html

I'm getting them in fully brushed aluminum. They are also availble in black and other sizes, but this one seems to be ideal for the UCDs. $44 each, plus shipping from Thailand, bank fees for payment transfer, etc.

This outfit also sells much larger enclosures with heat sinking, but it'll get expensive. I'm planning on attaching a custom 1/4" aluminum base plate under each unit to provide additional stability and heat transfer

Kevin Haskins · « **Reply #9 on:** 23 Dec 2005, 11:58 pm »

Excellent resource.

Let us know what the final price is landed after customs, shipping and bank charges. Usually I add about 15% to the price of Asian sourced parts to account for shipping & customs/duty. That is when it's amortized over a much larger order though and shipping via Ocean Freight. Usually single item purchases don't make much sense due to the transaction fees and the cost of air shipping.

BradJudy · « **Reply #10 on:** 24 Dec 2005, 05:30 am »

Those chassis do look nice. Please post when you get them and let us know about working with the company and the quality of the product. The DIY crowd on head-fi is always hunting for new sources of good cases and they have some nice looking ones.

speedcenter · « **Reply #11 on:** 13 Jan 2006, 07:07 pm »

Quote from: BradJudy

Those chassis do look nice. Please post when you get them and let us know about working with the company and the quality of the product. The DIY crowd on head-fi is always hunting for new sources of good cases and they have some nice looking ones.

I ordered 4 units - should arrive here in 8-10 weeks. The total cost was a very attractice $44 for each enclosure, an acceptable $50 shipping for all 4 combined and a "time to change your bank" $40 money transfer charge from my bank to pay for this. Seller cannot do paypal or credit cards.

So unless you want to buy more than 1, this is a rather expensive source.

Will update this thread when I get them.

got a few more pix of the thing here - all panels are aluminum:

http://didnt.doit.wisc.edu/audio/amplifiers/enclosure/

Peter

Kevin Haskins · « **Reply #12 on:** 13 Jan 2006, 07:56 pm »

We are having our chassis made in the USA at this point. I prefer steel because of it's strength and shielding properties. You really need a hefty enclosure to handle shipping with the large transformers. The metal will deform under the weight and shipping them will expose them to loads that you don't encounter under normal use.

Price wise we are paying about $70 each in 50 piece quantities for our current chassis with foam inserts and one box. That is without the feet and the outside packaging. I expect the monoblocks to be right in the same price range because most of the cost is in the labor.

Having it done local though has the advantage of flexiblity. I can pick up the phone and talk with the production guys. I can make changes without days of email delays. There is also a cultural divide whenever you are dealing with overseas suppliers.

speedcenter · « **Reply #13 on:** 14 Jan 2006, 03:24 pm »

I can see your point - however, I am getting the transformers separately (from you

) and don't plan on shipping these amps anywhere anytime soon.

I'm also adding a 1/4" polished aluminum plate to the base of the unit, as I prefer to put my components on roller bearings. The plate creates the perfect interface for the balls, while also adding structural strength to the base of the unit. At the same time it'll work as a heat sink for the UCD modules. Obviously, this is all one-off DIY. The main reason I chose those enclosures is really the appearance. There will be a lot of customizing inside as well: for example, I will have to create a rather large and strong L-bracket to mount the 100mm tall psu sideways. So when it's all said and done, I think I'll have quite a lot more than $150 in each chassis. I'm trying to do the rear panel drilling myself, but may just replace the whole panel with a Frontpanelexpress element, if the design allows for that. Right now I have not even decided what to use for the power inlet, switches, etc - plus I want to test out that XLR-RCA adapter cable before I decide how to wire it up in the enclosure.

Peter

Kevin Haskins · « **Reply #14 on:** 14 Jan 2006, 06:19 pm »

Yea... anytime you build a one-off item it cost $$$.

For our mono-blocks I'm making it tall enough to mount the power supply upright. I'm using the same heatsink we use with the multichannel products (but cut to a taller 4") and the softstart is going on a bracket to set it up on end. I'd considered setting the power supply on their side but it just takes up more real estate in the other dimensions. I wanted the two mono-blocks to sit side by side in a standard 3U rack space.