About a year ago I bought a SP9 octal pre amp kit from tubes4hifi. The instructions were minimal at best, but I got it together by looking at photos of previous builds. The preamp worked but there was unacceptable hum. The grid voltages were way off spec according to the schematic that came with the kit. I got in touch with Roy Mottram who couldn't decide if the voltages at the grids should be 129 as per his schematic, 55 volts as per 4 customers ( including myself) or 12 to 14 and 0 volts as per his email. He then stopped the voltage discussion altogether. After many hours of searching I found a problem on the pcb and advised Roy. His answer "OK, so it looks like you found an error on that board, that's good, that's how things get fixed". No apology or assistance of any kind - he said I could buy another pcb at my expense or have him fix it at my expense - Great service for a kit worth $1000.00 !
I have different take on it. I am not in any way associated with tubes for hifi or any other business for that matter. What you bought was a kit. You assembled it, you tested it and found it to be unsatisfactory. You probably learned a few things in the process one of which is to carefully inspect circuit boards. You are a better diagnostician now for having found it and if you understand how and why there was a mistake on the PC board, you will be better suited to building more kits or even amplifiers from scratch. Nobody's perfect and factories make mistakes. You found the problem. Be proud of yourself not angry at someone else. At the end of the day you only have control over you and your actions. Kudos to you for finding the problem.
The point I am making is that it shouldn't be up to the buyer to diagnose a problem with any kit - the bugs should be worked out before it goes on sale. Also the seller can't make up his mind on what the proper grid voltages should be ! I am now retired and have never dealt with a company that cares less about customer satisfaction , will not answer specific questions, and offers no compensation for their mistakes
Bankruptcy is a good excuse for a vendor to fail to support a faulty product due to error. Everybody please help this vendor achieve this goal.
I can't believe the number of times this vendor has been reccommended as being superior to the one I have used. Perhaps the reason is low price. When the vendor I use shipped the wrong part, they shipped me a replacement without charging the shipping fee (which was 3x higher than the parts price). Neither did they require me to spend $6 and a half hour at the post office shipping the wrong part back.
I can't believe the number of times this vendor has been reccommended as being superior to the one I have used. Perhaps the reason is low price. When the vendor I use shipped the wrong part, they shipped me a replacement without charging the shipping fee (which was 3x higher than the parts price). Neither did they require me to spend $6 and a half hour at the post office shipping the wrong part back.
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I had a similar experience with the exact same preamp. After assembly, my SP9 had hum, noise, and other problems that I was never able to get resolved to my satisfaction. The preamp did produce audio from both channels, but the result was not usable in my system and definitely not HiFi. After considerable time and effort, I gave up on this preamp and sold it for parts/repair and moved on to a different preamp. I exhausted my technical abilities and reached my financial limits on getting this kit working.
The OP has been trying to get his preamp working for a year without success. That pretty much says it all. My guess is he does not want to spend more time and money with this preamp, which may not ever work to his satisfaction. Tubes4hifi has a good reputation and, seemingly, many satisfied kit owners, but this particular kit is problematic. Anyone looking to build a preamp kit might want to avoid the SP9 Octal.
I think the title "buyer beware" is appropriate here and that is the right message when purchasing kits like these. These kits are NOT Dynaco or Heathkit mass-produced products that have a large user base with excellent documentation and support. These are small productions items, perhaps 12 or less, and the end result is very much up to the builder and his abilities to work through any and all problems, even if it involves some design changes. I guess I am saying that this is not really a kit, just a design and a collection of parts.
The OP has been trying to get his preamp working for a year without success. That pretty much says it all. My guess is he does not want to spend more time and money with this preamp, which may not ever work to his satisfaction. Tubes4hifi has a good reputation and, seemingly, many satisfied kit owners, but this particular kit is problematic. Anyone looking to build a preamp kit might want to avoid the SP9 Octal.
I think the title "buyer beware" is appropriate here and that is the right message when purchasing kits like these. These kits are NOT Dynaco or Heathkit mass-produced products that have a large user base with excellent documentation and support. These are small productions items, perhaps 12 or less, and the end result is very much up to the builder and his abilities to work through any and all problems, even if it involves some design changes. I guess I am saying that this is not really a kit, just a design and a collection of parts.
I must have spend 5-6 hours of support trying to help GarageGuy sort out his preamp over the course of a year. If I remember correctly he didn't even contact me until about 5-6 months after he bought it.
Several times I offered to fix it for him, but he always refused.
I've sold ten of these SP9 octal preamps, two people (both posted here) had problems they were unable to resolve. Two other people say it's the best preamp they've ever heard. No problems or comments from the other buyers.
I'm with MidNightMayhem here, after a year I told GarageGuy almost the exact same thing. You're not buying a finished product, you're buying a KIT, and so getting it to work correctly is ultimately your responsibility and problem, especially if you refuse to take advantage of the help that was offered.
I can only please 99% of people 99% of the time.
There are always going to be the 1% with any company or any product.
This will be my only response on this forum, I help people that actually want help, not people with complaints that refuse help
Tubes4HiFi
Several times I offered to fix it for him, but he always refused.
I've sold ten of these SP9 octal preamps, two people (both posted here) had problems they were unable to resolve. Two other people say it's the best preamp they've ever heard. No problems or comments from the other buyers.
I'm with MidNightMayhem here, after a year I told GarageGuy almost the exact same thing. You're not buying a finished product, you're buying a KIT, and so getting it to work correctly is ultimately your responsibility and problem, especially if you refuse to take advantage of the help that was offered.
I can only please 99% of people 99% of the time.
There are always going to be the 1% with any company or any product.
This will be my only response on this forum, I help people that actually want help, not people with complaints that refuse help
Tubes4HiFi
Since I have built both the noval and octal versions of the SP9 preamp, and they both work beautifully, I feel compelled to defend both the preamps and Roy here. First of all, here is the first thing you see when you look at his preamp kits page:
Documentation that is included with preamps is very basic instructions. PCB layout diagram, parts list, and schematic.
Wiring diagrams can be provided, but I assume a builder knows how to hook up the input signal, output signal, high voltage, and filament voltage.
Not much else to do besides that. Some people can't figure that out but most can, if you can't I can try to help via email. Roy states right up front that you will need some electronics backround to build the kits. Secondly, if you can get on the internet and attempt to destroy someones's reputation, you could just as easily use the internet to find out what the grid voltage should be on a 6SL7 in a class A audio amp application. About -1 to -2 volts with respect to the cathode, if the OP is still interested. It only took about a minute to find that information, not to mention if you look on the schematic that was provided with the preamp you will see it there also.
I find it sad that you are attempting to ruin Roy's business, there are very few kit vendors out there anymore, and none that I am aware of that offer as much value and performance as the SP9 octal. Having retailed car and home audio for 12 years, I know for a fact that there will always be disgruntled customers, no matter how hard you try to please them. Sad but true.
Documentation that is included with preamps is very basic instructions. PCB layout diagram, parts list, and schematic.
Wiring diagrams can be provided, but I assume a builder knows how to hook up the input signal, output signal, high voltage, and filament voltage.
Not much else to do besides that. Some people can't figure that out but most can, if you can't I can try to help via email. Roy states right up front that you will need some electronics backround to build the kits. Secondly, if you can get on the internet and attempt to destroy someones's reputation, you could just as easily use the internet to find out what the grid voltage should be on a 6SL7 in a class A audio amp application. About -1 to -2 volts with respect to the cathode, if the OP is still interested. It only took about a minute to find that information, not to mention if you look on the schematic that was provided with the preamp you will see it there also.
I find it sad that you are attempting to ruin Roy's business, there are very few kit vendors out there anymore, and none that I am aware of that offer as much value and performance as the SP9 octal. Having retailed car and home audio for 12 years, I know for a fact that there will always be disgruntled customers, no matter how hard you try to please them. Sad but true.
SP9, SP9, SP9...
My Octal SP9 works fine but I can hardly call it an SP9. Across the front are volume, balance, bass, mid, treble. It also has remote controlled volume and input selection.
I modified the circuit for DC coupling between the first and second stage and also the last and final stages. I also modified the circuit for 6SN7 tubes throughout. The regulated power supplies also required changes to accommodate the increased filament and current draw of the 6SN7 stages. And yes, there is plenty of gain with these tubes.
As always, I only ever purchase PCB boards from vendors and build and modify from there.
My Octal SP9 works fine but I can hardly call it an SP9. Across the front are volume, balance, bass, mid, treble. It also has remote controlled volume and input selection.
I modified the circuit for DC coupling between the first and second stage and also the last and final stages. I also modified the circuit for 6SN7 tubes throughout. The regulated power supplies also required changes to accommodate the increased filament and current draw of the 6SN7 stages. And yes, there is plenty of gain with these tubes.
As always, I only ever purchase PCB boards from vendors and build and modify from there.
Attachments
I would like first to reply to Troy Madden. Tubes4hifi make an excellent driver board for the ST70 ( I have bought two). I am only referring to the SP9 octal kit. I unfortunately, along with jsfinusa, bought one of the original kits (version 1). We both had the same noise/hum/ voltage problems . jsfinusa sent his back for repair ( he was charged $150.00 plus shipping to and from) it still had the problem and he ended up selling it for parts or repair. Roy agreed that there was a problem with my pcb , but I would have to buy a new one. When you were in the retail business business and confirmed to a customer that they had bought a defective audio unit , did you ask them to pay for another one? As for Roy , I was in contact with him from the beginning because of missing parts, a bad tube and noise/hum ( I have the emails to prove it). He said of all the dozens of SP9 octal kits he sold , I was the only one with problems- now he says he sold 10 and two of us have problems! I will not return it because of the of the experience jsfinusa had. All I asked for is a version 3 pcb at no charge ( he is at version 3 after 10 sales I guess version 1 and 2 had problems)
I don't think there is much to be gained by arguing back and forth. If there was a improper trace on the board, that is regrettable, but that can be can be fixed. I have built several of Roy's preamps for myself and for friends, and I know for a fact that they can be built to be free of excess noise or hum. In my experience, noise/hum problems are generally caused by a ground loop in the signal input or/or output wiring, improper grounding of the circuit board, a problem with the B+ voltage regulator, or a poor layout of wiring or components. Make sure that you have at least a 15 to 20 volt drop across the B+ regulator. If you don't, you will have hum in the B+, as the regulator will be unable to filter it out. Make sure you don't have any ground loops, a ground loop will cause noise in an otherwise perfectly good preamp. If you want to PM me with your email address, I will send you pictures of my wiring and layout.
I have mixed feelings about this. I too bought something from Roy: a Dynaco ST70 upgrade board which had not been thoroughly tested, as it was missing eyelets for filament voltage for one of the 3 tubes. While not really a huge deal, it could have stumbled a beginner like me. So I wrote an email to Roy and he said there was a mistake and explained that I need jumpers to be run from another tube. Of course, it fixed the issue but doesn't give me an impression of a complete product.
So here is the other side: once I got pass the hurdle, my Dynaco really benefited from the upgrade. The final product sounds pretty freaking awesome. And people who know these kits confirm: the circuit design is great.
BTW, the board I had is version 15. Who knows what version we are on since! It sounds like Roy needs to stop selling intermediary versions and concentrate on a more solid product line.
Another weird thing: there is a price mismatch of $10 from his site to eBay, also sold by him. And that's on a $40 item!
So here is the other side: once I got pass the hurdle, my Dynaco really benefited from the upgrade. The final product sounds pretty freaking awesome. And people who know these kits confirm: the circuit design is great.
BTW, the board I had is version 15. Who knows what version we are on since! It sounds like Roy needs to stop selling intermediary versions and concentrate on a more solid product line.
Another weird thing: there is a price mismatch of $10 from his site to eBay, also sold by him. And that's on a $40 item!
When you buy a kit, you automatically assume it's been tested and is going to work. When you get a defective circuit board that has issues, your not getting what was advertised or expected. There's no excuse for selling defective boards. Roy is just counting his money and advertising, NOT looking at quality control. He should have sent a new board or refund, to show he's a stand up man......
Yes- there's a big difference between a kit not working due to miswiring or bad assembly practice on the user's part, and a design that is inherently lacking connections, or otherwise faulty. Sounds to me like all the headache of a scratch build with the added bonus of paying someone else's profit, meager though it may be, on top for kicks.
Weird...I built an amp using Roy's VTA Dynaco upgrade board 7 years ago, and it
was fairly clear from the documentation that the heater wiring
for one of tubes has to be taken from one of the other tubes.
It worked first time and sounds great.
Just sounds like Tubes4hifi has room to improve here and there.. Attitude and items quality appear to be inconsistent; sometimes good, others a complete failure.
Having on hand the complete (FULL) documentation is of the easiest ways to avoid issues building up a device from a kit. Not a wise move certainly to just include basic information with the kit.
Besides this, a faulty PC board must be replaced at the seller's full expense. No excuses. Even a Chinese does that
Having on hand the complete (FULL) documentation is of the easiest ways to avoid issues building up a device from a kit. Not a wise move certainly to just include basic information with the kit.
Besides this, a faulty PC board must be replaced at the seller's full expense. No excuses. Even a Chinese does that
The main (and often only) reason to buy a kit is to get a debugged, tested and easy to build circuit which doesn't need extensive technical knowledge from the builder to be successful. Those experienced enough in electronics to troubleshoot and correct production mistakes in a kit could design and build their own circuit from scratch and doesn't need a kit. There are no excuses for (undocumented !) errors in PC boards and this should have been corrected before offering the kit for sale, and the board replaced free of charge. This is just unethical.
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