Roy Mottram's SP-6 Preamp Board/Kit Decisions ?????

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Roy Mottram's SP-6 Preamp Board/Kit Decisions ?????

Postby hilldweller » Sun Aug 26, 2007 4:29 am

Hi All,
Has anyone had experience with this preamp design?? I was considering to use this in a Dynaco Pat4 chassis. I would like a GOOD tube based preamp. I do not have enough experience to decide which one to get. I would like to build it myself. I don't wan't to spend truckloads of cash. I appreciate anybody's input. Yellow_Light_Colorz_PDT_11
http://www.tubes4hifi.com/pre3.htm
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Postby TerrySmith » Sun Aug 26, 2007 7:14 am

I think it is an excellent idea. All of Roy's stuff is high quality. I like this particular design as everything is on one board.

I also picked up a PAT-4 for the same reason, it's in physically perfect shape, someone did a extra neat assembly on it, so I kinda hate to gut it. Maybe I'll find another.
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Postby Sal Brisindi » Sun Aug 26, 2007 8:25 am

I think the price of his bare circuit board is a bit pricey at $119. If you go to this website http://www.lh-electric.4t.com/projects/sta1pjct.htm you can buy a Stereo preamp circuit board for $15.00 including shipping or a complete kit not including the tubes for $55 or $59, I forget. The links are broken on the bottom of the page to order them, I am sending a email about the broken links now, they worked a few months ago.

Regards,
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Postby hilldweller » Sun Aug 26, 2007 8:27 am

Thanks Terry, I appreciate your input. I'll let the forum know how it turns out. I'm not fully decided yet. Yellow_Light_Colorz_PDT_20
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Postby SDS-PAGE » Sun Aug 26, 2007 8:54 am

That's pretty cool link, Sal. The prices are very reasonable too. I only wish that preamp kit came with a phono stage though.
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Postby TerrySmith » Sun Aug 26, 2007 9:14 am

It appears with Roy's board you won't have to hard wire a power supply, both B+ and filament, and also the wiring between the seperate boards.

So between buying this vs new replacement boards and a cap board, cost will be a wash. Plus, Roy's board has improved circuitry.

I'll be buying a bare board and sourcing my own parts, Dale resistors, maybe orange drop caps or I might try the russkie PIO caps. Most parts I have on hand anyway.

Another idea I have for preamps is to fab a bracket and move the selector switch rearward close to the input strips for shorter wiring and less noise, and use a sleeve and extension shaft for the knob.
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Postby hilldweller » Sun Aug 26, 2007 9:55 am

TerrySmith wrote:It appears with Roy's board you won't have to hard wire a power supply, both B+ and filament, and also the wiring between the seperate boards.

So between buying this vs new replacement boards and a cap board, cost will be a wash. Plus, Roy's board has improved circuitry.

I'll be buying a bare board and sourcing my own parts, Dale resistors, maybe orange drop caps or I might try the russkie PIO caps. Most parts I have on hand anyway.

Another idea I have for preamps is to fab a bracket and move the selector switch rearward close to the input strips for shorter wiring and less noise, and use a sleeve and extension shaft for the knob.


Thanks Terry, After looking at several designs, I'm leaning towards roy's design. The board only option is a little pricey but you are paying for the design and research not just the material. I like the circuitry in this one. I'll be selecting my own parts as well. Shielded wire and ground bus will be incorperated. There are other low noise construction techniques that can be incorperated without moving controls, in/out ect. My system will be powered through a power conditioner I found at Fair Radio Sales.
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Postby snitch56 » Tue Aug 28, 2007 11:08 pm

Is there a simple modification to Roy's board to allow for tone control support?
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VTA SP6 preamp

Postby tubes4hifi » Thu Nov 01, 2007 11:04 pm

Hi all, it's been awhile since I've had time to check out these forums, been pretty busy!!
Just wanted to let all know that if I had more than one or two people wanting this PCB I could easily get the price to $79, or complete parts kit for $179 (this is assuming 4 or more buyers within a month period).
I also have a fully built up SP6 pre in a PAT4 chassis, total investment of $490 as the PAT4 was like brand new, the preamp sounds great and the phono section is dead quiet, I'd be willing to sell the whole package for $379 (this ONE only!!) as I've just got too many extra amps & preamps laying around at the moment.
I don't know of anyone selling a combo line stage/phono stage/power supply all-in-one PCB for anywhere under $500 let alone under $200, so it's a nice deal.
Roy www.tubes4hifi.com/pre3.htm
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Re: VTA SP6 preamp

Postby hilldweller » Fri Nov 02, 2007 7:37 pm

tubes4hifi wrote:Hi all, it's been awhile since I've had time to check out these forums, been pretty busy!!
Just wanted to let all know that if I had more than one or two people wanting this PCB I could easily get the price to $79, or complete parts kit for $179 (this is assuming 4 or more buyers within a month period).
I also have a fully built up SP6 pre in a PAT4 chassis, total investment of $490 as the PAT4 was like brand new, the preamp sounds great and the phono section is dead quiet, I'd be willing to sell the whole package for $379 (this ONE only!!) as I've just got too many extra amps & preamps laying around at the moment.
I don't know of anyone selling a combo line stage/phono stage/power supply all-in-one PCB for anywhere under $500 let alone under $200, so it's a nice deal.
Roy www.tubes4hifi.com/pre3.htm

Your out for the bucks I can see. How can you charge so much for simple circuits and circuit boards? I bet you don't sell to much of these. If you do, There is a lot more fools with money than sense. After all that said, I hope you do well in your ventures. You inspired me to come up with a circuit board and charge megabucks! I know about R.A.D. And associated costs. It is a one time expense that is recouped after the first year of sales. I will offer complete kits with premium parts at a REASONABLE COST! I'm a working man and appreciate the "Depleted Value Of A Dollar" and will make the best of it!!!
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RE: SP6 preamp

Postby tubes4hifi » Fri Nov 02, 2007 8:11 pm

I sell most everything for 10-20% over cost, maybe if you've never had any PCB designed, tested, and manufactured then you don't know about the 8-12 hours of design time and the $100 setup fees, so 2 PCBs cost me $150 but I can get 10 of them for $300. If you can get them cheaper I'll buy them from you instead. And since this is just a part-time hobby for me, I just sell to whoever wants to buy, most of my customers are referrals and repeat customers anyway.
I've been kind of surprised Shannon hasn't come up with a preamp offering yet, as the cheapest kit I've seen lately is the Foreplay for about $429 and IMHO not worth half that.
Have you looked at the schematics of many commercial hi-end preamps lately, you know, the ones that go for $2000-4000 for a simple line stage?? ARC, BAT, C-J, Cary, etc??
They can be duplicated for about $200-300 in parts in you don't care what it looks like, but the end result is the same, I sold many a clone of an $7500 European preamp a few years back for $400.
Don't forget this is a combo line-phono-power supply, find me a better deal and I'll buy a dozen of them myself!!
Roy
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Postby Shannon Parks » Sat Nov 03, 2007 6:22 am

Roy's bare ST70 drivers are very inexpensive (I wish he's raise his prices!), so I doubt he's trying to gouge anyone.
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