Thanks for yout response BriKs...I was reading more about the R15 implementation in 6L6’s build guide. I am going to mount R12 and R15 with 39.2K and 2.21K respectively and then follow the guidelines for biasing the amps based on the power supply used. I will try the 19V laptop supplies first, but as I mentioned they may be noisy.
No one has commented on my question regarding Zen’s reference to the “lower position” he says would be the correct place to try the Semisouth transistor in the ACA.
You mentioned the “upper mosfet” in your response. Are we all referring to the original circuit drawing in simple terms here as to the position in the diagram that the transistors are found?...or is the “upper/lower” designation of the transistors a technical reference relating to the function of them within the circuit?
I just want to be clear that if I decide to try the Semisouth in this circuit that the “lower position” he is referring to is in fact Q1 in the circuit diagram.
Seems like this time next month till kits are in stock if you read here: Amp Camp Amp Parts Kit – diyAudio Store
Mark (I know your name because I personally answered several of your emails on the helpdesk), please think twice before you post in public on this topic again.
You wrote to the helpdesk in March complaining that you had yet again missed out on the ACA, because the chassis had sold out by the time you tried to order. I felt for you because I know you are very keen to get building. I could feel your disappointment and your energy and excitement to get started with building your ACA.
So in that email I told you that you didn't have to wait until July, you had a small window of quite literally a few minutes to secure yourself a kit, and that we'd be shipping a chassis in "two weeks". So you ordered a parts kit (beating several hundred people to the post), and have since been waiting for your "catch up" chassis. Please keep in mind that if you hadn't secured the parts kit, within minutes they would have been sold out and you would have had to wait until July to make your ACA.
Please do not post factually incorrect information.
All enclosures ordered in March (about 65) were manufactured several months earlier. When we made the ACA available for sale in March, all available chassis sold out immediately and Hifi2000 shipped them all straight out off the factory floor within 48 hours to the lucky 65 recipients. You can already see some of them as completed amps in the build thread, and the ACA reviews page.
We later did a special mailout to take special care of people who bought March kits but missed out on a chassis (you were part of that group). We didn't want you either waiting until July for the next batch, nor to get a chassis that didn't exactly match. That's just how we are - we try whenever we can to go beyond the call of duty to look after every single customer even if it means a lot more work for us.
You ordered your chassis on April 3rd, and what you are talking about above appears to be this small batch of "catch up" chassis. You are absolutely correct, they haven't shipped yet.
On April 10th we emailed you and said:
"We are expecting to have the ACA chassis to be ready somewhere between end of April to early May."
On April 17th you emailed asking for an updated ETA. I spoke to Hifi2000 for you, and replied with the information that they expect to ship by the end of the following week (which would be Friday 27th April). This is in line with what we said to you on April 10th (End of April to Early May).
So where are we at today? I just spoke to Gianluca again for you (Hifi2000 has been following all your emails in the helpdesk). They are waiting on their anodization partner who is running late, and the current ETA is early May. So that's where things sit.
I'm very sorry about the delays, because the mantra I often quote myself is that the store's goal is to "under promise and over deliver". Right now on your batch of "catch up" chassis, we have failed that because we really would have liked to have shipped mid April, but these things happen in manufacturing. Please know that this is a special order we are doing just for you (and others who missed out on a matching chassis). We aren't Apple, your chassis is being hand made for you just so you can complete your ACA without having to wait until July.
Please.
OK. Can you please disclose the information prior to the pre-sale quickly approaching? A few interesting possibilities have been discussed. If those possibilities are going to end up in a more distant future ACA release, I need to wait for that... simply because I can't afford the cost of doing this twice.
I think we can all understand Mark's frustration, because we've all felt it ourselves at some time in our lives when we feel like things aren't happening fast enough and the goal posts keep moving away every time we seem to get close to them. While I think the message could have been delivered a bit differently, there is an important message in this. And that's that most problems arise where expectations are not met.
When we sold out the ACA in March in the blink of an eye, we had lots of frustrated members ask us why we didn't just do a pre-order? "It's not rocket science". That's true. But the reason we have done very few pre-orders lately is because of problems that arise like this one.
If you don't hit your shipping date, all of a sudden you start getting emails asking where things are at. And then cancellations, changes, etc which start chewing up hours better spent doing the job. It's a massive headache, and nobody likes headaches.
I guess the solution is to just follow the mantra of "under promise and over deliver". Add an extra few months to the shipping date, and make sure you ship early. Alternatively, do what we did for a long time and just don't do pre-orders and make life much easier for ourselves. But then you get situations like the March ACA sale where demand was greater than supply. It's a conundrum. The ACA has been out of stock for over a year... that would have been a long wait for your pre-order.
Last year we did pre-orders on some of our products. As much I think equally for the benefit of people who wanted to lock them in, as for ourselves to capture sales. They were delayed by several months. Nothing we could do about it other than having redundant suppliers (not an option) - we rely on other people, and those people rely on other people, and so it goes on.
The problem for us is that there are many things beyond our control. Nobody likes to deal with people who are angry with you about something that's out of your own control. Take for example this situation here - Hifi2000 told us "two weeks", and that's what they thought at the time was a fair estimate. Now they have a piece of their jigsaw puzzle which is out of their control - their anodizer is running late and there's public holidays (it's always holiday season in Italy!). It's not something they anticipated, but when I told Mark "two weeks" I should really have said "Our current estimate is two weeks, but you should be prepared to wait up to two months if unexpected issues arise in the manufacturing chain of events".
I'd like to take a moment to talk a little about why things take time. Hifi2000 is like many other fabricators in the Modena/Bologna region, a small, multi-generational family operation. They do one thing and they do it well (fabrication, CNC, finishing, etc). They've been doing it for 50 years and the staff have all been there a long time. This is a common feature of workshops in the region, and you will find grandma, "mamma", and the children all working in the same business passing down the skills and knowledge generation to generation. I've also visited their specialist fabrication partners they rely on for things they don't do themselves - like spray painting and anodization and they're much the same - one family with grandparents, parents and children all dedicated to doing one job really well.
In Italy if you have a big order come in to your factory you can't just hire a temp worker to deal with the increased load. They have unions and labour laws up the razzoo. If you hire someone you can't fire them, it's pretty much "you're hired for life". That makes dealing with the ebb and flow of business very difficult. However on the plus side, it means that when you buy a chassis from us (or directly from Hifi2000) you know you're getting a product that has passed through the hands of many artisans in their trade who have taken great care to get you the best product possible. It wasn't slapped together by a temp worker, and you have paid for (and can expect) a great quality product.
Evidence of that is for example in the covers and heatsinks. On the covers one side is perfect, the other might contain scratches, anodizing marks etc - great care is taken to preserve the exterior "finished product" side of all the panels. Same for the heatsinks (in which you'll notice anodization marks on the inside not the outside). Every piece of each chassis is individually wrapped in soft plastic to preserve the aesthetic. I've seen side-by-side comparisons of Chinese made faceplates and the Hifi2000 ones and the brushing and corner rounding on the Chinese ones was as we Australian's would say "rough as guts".
That's not to say there are never problems. Mistakes happen. It's how you deal with them that makes the difference. I can faithfully say that both the diyAudio store and Hifi2000 do everything we can to resolve any customer issues to the satisfaction of the customer.
Things are still being discussed but this is what it looks like:
Parts Kit
* Upgrading rear toggle switch to beefier one (Parts Express 060-538) with 6.4mm dia hole (hopefully we can do the anti-turn washer "dimple" in the rear panel, just a nicety)
* Upgrading rear DC jack to beefier one (Digikey 839-1292-ND) with 11mm dia hole
* Upgrading PSU to a Meanwell 24V 5A GST120A24-P1M (This will be available for purchase directly from the diyAudio store with a bundled IEC power cable)
* Adding "classic" round black ACA front power switch
* Including some blue LEDs as well as the red
* Including XLR jack
Chassis
* Middle of the front panel will have a 20mm hole for the new power switch (that will for "modding" purposes also support the commonly available 19mm vandal type switches which have a 22mm bezel, and available in momentary/latching/capacitive/piezo, customisation options a-plenty)
* Offering the chassis in black and silver
* Offering the chassis with and without front power switch hole (for people that either like a clean front look, rear power switch or want a matching chassis for their March chassis)
* Please note - these changes might... change before the pre-sale starts, or even slightly change before we ship. Let's say 85% confidence at this stage this will be the change set.
When we sold out the ACA in March in the blink of an eye, we had lots of frustrated members ask us why we didn't just do a pre-order? "It's not rocket science". That's true. But the reason we have done very few pre-orders lately is because of problems that arise like this one.
If you don't hit your shipping date, all of a sudden you start getting emails asking where things are at. And then cancellations, changes, etc which start chewing up hours better spent doing the job. It's a massive headache, and nobody likes headaches.
I guess the solution is to just follow the mantra of "under promise and over deliver". Add an extra few months to the shipping date, and make sure you ship early. Alternatively, do what we did for a long time and just don't do pre-orders and make life much easier for ourselves. But then you get situations like the March ACA sale where demand was greater than supply. It's a conundrum. The ACA has been out of stock for over a year... that would have been a long wait for your pre-order.
Last year we did pre-orders on some of our products. As much I think equally for the benefit of people who wanted to lock them in, as for ourselves to capture sales. They were delayed by several months. Nothing we could do about it other than having redundant suppliers (not an option) - we rely on other people, and those people rely on other people, and so it goes on.
The problem for us is that there are many things beyond our control. Nobody likes to deal with people who are angry with you about something that's out of your own control. Take for example this situation here - Hifi2000 told us "two weeks", and that's what they thought at the time was a fair estimate. Now they have a piece of their jigsaw puzzle which is out of their control - their anodizer is running late and there's public holidays (it's always holiday season in Italy!). It's not something they anticipated, but when I told Mark "two weeks" I should really have said "Our current estimate is two weeks, but you should be prepared to wait up to two months if unexpected issues arise in the manufacturing chain of events".
I'd like to take a moment to talk a little about why things take time. Hifi2000 is like many other fabricators in the Modena/Bologna region, a small, multi-generational family operation. They do one thing and they do it well (fabrication, CNC, finishing, etc). They've been doing it for 50 years and the staff have all been there a long time. This is a common feature of workshops in the region, and you will find grandma, "mamma", and the children all working in the same business passing down the skills and knowledge generation to generation. I've also visited their specialist fabrication partners they rely on for things they don't do themselves - like spray painting and anodization and they're much the same - one family with grandparents, parents and children all dedicated to doing one job really well.
In Italy if you have a big order come in to your factory you can't just hire a temp worker to deal with the increased load. They have unions and labour laws up the razzoo. If you hire someone you can't fire them, it's pretty much "you're hired for life". That makes dealing with the ebb and flow of business very difficult. However on the plus side, it means that when you buy a chassis from us (or directly from Hifi2000) you know you're getting a product that has passed through the hands of many artisans in their trade who have taken great care to get you the best product possible. It wasn't slapped together by a temp worker, and you have paid for (and can expect) a great quality product.
Evidence of that is for example in the covers and heatsinks. On the covers one side is perfect, the other might contain scratches, anodizing marks etc - great care is taken to preserve the exterior "finished product" side of all the panels. Same for the heatsinks (in which you'll notice anodization marks on the inside not the outside). Every piece of each chassis is individually wrapped in soft plastic to preserve the aesthetic. I've seen side-by-side comparisons of Chinese made faceplates and the Hifi2000 ones and the brushing and corner rounding on the Chinese ones was as we Australian's would say "rough as guts".
That's not to say there are never problems. Mistakes happen. It's how you deal with them that makes the difference. I can faithfully say that both the diyAudio store and Hifi2000 do everything we can to resolve any customer issues to the satisfaction of the customer.
Things are still being discussed but this is what it looks like:
Parts Kit
* Upgrading rear toggle switch to beefier one (Parts Express 060-538) with 6.4mm dia hole (hopefully we can do the anti-turn washer "dimple" in the rear panel, just a nicety)
* Upgrading rear DC jack to beefier one (Digikey 839-1292-ND) with 11mm dia hole
* Upgrading PSU to a Meanwell 24V 5A GST120A24-P1M (This will be available for purchase directly from the diyAudio store with a bundled IEC power cable)
* Adding "classic" round black ACA front power switch
* Including some blue LEDs as well as the red
* Including XLR jack
Chassis
* Middle of the front panel will have a 20mm hole for the new power switch (that will for "modding" purposes also support the commonly available 19mm vandal type switches which have a 22mm bezel, and available in momentary/latching/capacitive/piezo, customisation options a-plenty)
* Offering the chassis in black and silver
* Offering the chassis with and without front power switch hole (for people that either like a clean front look, rear power switch or want a matching chassis for their March chassis)
* Please note - these changes might... change before the pre-sale starts, or even slightly change before we ship. Let's say 85% confidence at this stage this will be the change set.
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You forgot about option for custom engraved front panels with “ George” in a facsimile of Nelson’s own handwriting.
If the SMPS is upgraded to the Meanwell, is that the caged unit, and intended for internal use? If so, how would the AC entry be accomplished for those closing to run a pair in bridged mono-block mode, thereby needing to use the rear panel hole currently allocated for XLR sized jack, which could otherwise be populated with a Neutrik powerCon. Once you create a list of options, you might end up with at least 2 or 3 rear panel configurations - then watch the shopping cart and supply chain nightmares escalate.
If the SMPS is upgraded to the Meanwell, is that the caged unit, and intended for internal use? If so, how would the AC entry be accomplished for those closing to run a pair in bridged mono-block mode, thereby needing to use the rear panel hole currently allocated for XLR sized jack, which could otherwise be populated with a Neutrik powerCon. Once you create a list of options, you might end up with at least 2 or 3 rear panel configurations - then watch the shopping cart and supply chain nightmares escalate.
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Yes your concerns would be a problem if they were the case, however the new PSU is an external one, and about twice the size and weight of the previous one, with much less "noise", 24v. 5A instead of 19v 4.7A, and about 6X the price. There will be no PSU options other than getting one elsewhere as it will be sold separately from the rest of the kit. It's a pretty darned great PSU though, and the ACA deserves it.
It is true that the holes for the XLR are very useful for any number of fittings, and fiendishly hard to drill at home..
It is true that the holes for the XLR are very useful for any number of fittings, and fiendishly hard to drill at home..
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You can always mock up a DXF and have your own 10mm panel CNC cut one or both sides completely your own specification using the CNC Work on 10mm Aluminum Panels service. If you post the DXF file others can use it too. There are lots of programs out there that can export appropriate DXF files and Hifi2000 can import DXF straight into their CNC machine. The front panel is 240mm wide x 90mm high. Watch out for the heatsinks and heatsink brackets if you are planning through-hole parts
The Meanwell GST120A24-P1M is a laptop style plug and play replacement for the previous PSU, uses the same plug and is suitable for use with all previous ACAs (I believe an adjustment may be necessary, mentioned earlier in this thread).
As for hacking up your own rear panel, well for starters and by intention it's 4mm aluminum which is very early to drill, file or cut. Any good tool will cut through it easily.
Additionally if you like you could order a blank rear panel (good idea, I'll make sure that can be purchased as a standalone item) and DIY it to exactly your own specifications. All you need is a ruler, a center punch, a drill and some HSS drill bits.
Or make a DXF and use the Aluminum panel CNC service to have it professionally machined to your specifications. The rear panel is 155x80 and again watch the heatsinks and heatsink brackets
And yes I agree with Variac that the 3 hole XLR pattern is fiendishly hard to drill yourself!
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Ah, I got distracted writing my long email above...
Something we're not doing very well is keeping people who have made pre-orders, informed about what the current expected shipping date is. This is something I'd like to remedy. The current plan is to write some software that will manage all pre-orders and keep everyone who has made one aware of the exact status of their order, with weekly email updates and a login where they can see this status at any time.
That's something for later in the year, certainly after we have migrated diyAudio onto the next platform (which I'd like to have completed within the next 2 months, but will probably end up being 4).
Something we're not doing very well is keeping people who have made pre-orders, informed about what the current expected shipping date is. This is something I'd like to remedy. The current plan is to write some software that will manage all pre-orders and keep everyone who has made one aware of the exact status of their order, with weekly email updates and a login where they can see this status at any time.
That's something for later in the year, certainly after we have migrated diyAudio onto the next platform (which I'd like to have completed within the next 2 months, but will probably end up being 4).
Maybe not relevant but good and cheap psu can be found at you're local computer store.
Toshiba and HP (and others) generally use good quality psu and when the laptops break down the psu normally remains. Just ask the guys at the store.
For example, I'm using used Deltra Electronics psu for several projects. Stable, reliable and cheap.
Toshiba and HP (and others) generally use good quality psu and when the laptops break down the psu normally remains. Just ask the guys at the store.
For example, I'm using used Deltra Electronics psu for several projects. Stable, reliable and cheap.