seppoman

Hi Wilba, interfacing unbalanced and balanced equipment is normally no problem. When using a purely balanced input with unbalanced source, you just loose 6dB of volume and of course the increased noise immunity of a balanced signal. But with line levels and short cables (max. 10 m) you´ll hardly notice any negative effects. It would be possible to make the SID output symmetrical, but you´d need several parts (transformers or OpAmps) per channel and the only real advantage would be in live situations that you could make stage technicians happy cause they need less DI boxes ;) Seppoman

Of course they can be chained :) The only question is software support. Seppoman

yes, good example. Thorsten ordered them so I´ve put them there. Any more questions? ;) @Thorsten: just press Reload ;) Seppoman

Hi, it´s preview time again :) As the TLV has no way of adjusting the offset via software, 8 trimpots were added. Also a 74HC595 to provide 8 gate outputs :) New board size is 8x8 cm. Seppoman

Actually they don´t - this is what makes it so hard to drop them ;) Seppoman

I have a 6581 R4 installed. And a few others lying on the shelf - got to test them in this regard some time... Seppoman

Hi, (Sebo: option D was not meant to support less than 8 channels, this would give too many tiny boards and connections for people needing lots of channels.) UPDATE: I´ve discussed the matter extensively with Thorsten, and decision was made that I will use the TLV5630. Actually, the original reason for a new design was not to get better specs than the MAX525, but to have an alternative board with an easy-to-get and cheap DAC. The big majority of future CV users in context with Midiboxes will be people wanting to add some filters/VCAs/external effects etc. to synthesizers like MBSID or MBFM. For this purpose, the TLV is perfect. A lot of shops sell it (Digikey, Mouser, Jameco, Newark, Farnell, to name a few), it´s cheap and the specs are absolutely sufficient for this purpose, and SOIC is easier to solder than LQFP. So this decision puts the needs of many over the needs of a few. I´m really sorry for the modular guy(s?) - actually, the response to my "poll" looks like stryd_one is nearly alone with near-future modular plans, so sorry, Todd :-\ It´s really sad having to give up the 5392, but putting emotions and perfectionism aside I understand that using a nearly unavailable DAC for an official MBHP module just doesn´t make sense - the problems with the MAX525 are not to be forgotten... But as I´ve already got 2 AD5392s lying around here and the PCB layout is kind of completed, I´m thinking of ordering two PCBs anyway, just to play around a bit and to have a souvenir from all the wasted time ;) So if someone feels able and willing to write a driver for it and use it in a custom project, I´m offering to send one PCB with presoldered DAC for PCB+shipping costs (probably around 20 EUR - contact me via PM) - Todd? :) Anyway, the TLV board is in progress and I´ll keep you all posted :) Seppoman

Hi Rio, don´t know exactly what you mean with triple filtering and AND-Command, but my 6581 can combine different filter modes. Also, it does play all mixed waveforms correctly. I´ve noticed TK´s 6581 demo, so some 6581 do have problems there - mine doesn´t. Seppoman

Hi, About the different SID versions: The 6581 was used in the oder "breadbox" C64s, the 8580 in the newer ones. The 6582 was never used in production. There are different rumours why this chip was designed. Some people say it was meant for the C65 (successor to the C64, never sold, only prototypes exist). So the 6582 is the successor of the 8580 (audible differences are said to be subtle) and is quite hard to find. About "inferior 6581" - that´s a matter of taste. Technically, the 6581 is inferior, much more background noise, the filter is weak regarding cutoff range. Personally, I prefer it over the 8580 anyway, because it has more dirt, the filter is gritty and growling unpredictably. My reason for loving the SID is that it can sound so LoFi and 80s. The 8580 is just cleaner and in some way fatter. For clean and classical fat sounds, I´ve got an Alesis Micron, so I really wanted some opposite to it :) But I know I´m one of the few 6581 defenders here, most people prefer the 8580/6582. To learn more about Wilba´s PCB, just read here: http://www.midibox.org/forum/index.php?topic=9238.0 From what I understand, Wilba is modifying the PCB for complete V2 compliance and has added selectable SID voltage per pair, so that you can use all SID types. Building a single MBSID on breadboard is a good experience (see my attempt on it: http://www.midibox.org/forum/index.php?topic=4873.0). You´ll learn a lot about how everything works and will be prepared to build a big version that suits your needs afterwards. Seppoman

http://www.ucapps.de/pic16f_firmwares.html :)

Yes, this display is ok. Seppoman

This info is stated in the datasheet of your actual CD4051 variant. But normally the acquisition time of the ADC will be much higher than this. You can just get one AD value, switch to the next channel and wait perhaps a few NOPs. Seppoman

Hi, The 4685 is only needed for MBSID V2. There are no changes to the core module for it. There are a lot of different PIC18Fs. Of course, Microchip offers this variety for some reason, i.e. they all have different features, RAM/Flash sizes, integrated peripherals, number of pins etc. The MBSID needs the features of the 4685 (especially the CAN bus), so you can´t simply use another type. If you can´t buy 4685s in Poland, ask SmashTV or Doc, or try to get samples from Microchip. Seppoman

Nice idea :) So I see nobody jumps in for option E yet? Of course the modular approach could also be done with other DACs - but it looks like HQ specs are more important than price and easy availability? Please guys, I need statements from more people :) Whoever reads this and plans to build an AOUT sometime, please tell me your point of view! I need some information on what you need - is excellent precision worth the trouble of using a hard to source DAC? Would you participate in some kind of group buy so that SmashTV would have enough initial buyers to make ordering a pack of these DACs a calculateable risk? Are there a lot of people who want 16 CVs or more with enough precision to drive VCOs or do most people only want a few channels to do a bit of external filtering for MBSID anyway? I need to get a better feeling of what the most important goals for this project are! Thanks, Seppoman

I also like the modular idea, although I´m not quite sure if (and how much) signal degradation is caused by this. I suppose it would be a good idea to keep these connections as short as possible. The amount of work doesn´t differ so grossly that it would be a reason to choose one option - except, obviously, option A is least work ;) For people already having a working AOUT, there´d be no need to upgrade. The cirquit is quite the same. Only for new builders, one could think of doing a MAX525 board that in conjunction with the OP board replaces the old version so they have the advantage of a board with bipolar option already included. Thanks for your comment! In general: If somebody comes up with an option F or G, just go ahead - this is not only a multiple choice test :) Seppoman

GREAT CATASTROPHY!!! :( Last time I had checked the availability of the AD5392, it was in stock at Farnell and Digikey. Today I checked again and Farnell only lists the LFCSP package. Digikey marks it "only by request", minimum order for NON ROHS-conform 15 pieces, ROHS conform only trays of 160 pieces. This means, the 15 pieces minimum (which probably would be ok for SmashTV or a group buy) will probably disappear from the listing, and 160 pieces is way to many! So how should we go on with this project? LFCSP would be DIYable with the "table grill" technique, but I´m sure the ordinary DIYer can´t be bothered with a part that has no normal legs... Options: A. keep the module as it is, try to persuade SmashTV to stock up a few and hope that the availability gets better again. AD keeps listing the part as in production. B. Use the 16 channel version AD5390. Availability is ok (Farnell 47,30€ (more than 10 pieces: 35.70€) Digikey 28.10€). The price per channel is better (actually the price is still lower than for 8 channels of MAX525...), but we´ve also got to keep in mind the people who don´t need more than 8 channels who´d have to spend more money this way. And there´s no chance of putting everything on 10x8 cm including bipolar option for all 16 channels. Probably possible: 16 channels but only 8 with bipolar option. C. 5390 is pin compatible with the 5392, so I could add only a connector for the additional 8 channels and supply to the current design. Then it would be possible to use either the 5392 (if available) or otherwise use the 5390 and add an external OpAmp module D. split the AOUT board in two parts: When thinking this idea further, why not do only one small DAC module suitable for both 5390 and 5392, design an 8 channel OpAmp/bipolar module and connect one or two of them to the DAC board. This would probably make the "I want 64 channels" crowd happy and would simplify future changes to other DACs. E. say goodbye to AD and put one of the other previously discussed DACs on the AOUT. LTC2620 (RS 15€, Digikey 12.70€. INL 4LSB) or TLV5630 (Farnell 13.30€, Digikey 11.40€. INL 6LSB). Accept the lesser quality for easy to source and cheaper parts. (I suppose this option doesn´t sound too great to you as there is/was the opportunity to have a really HQ AOUT?) I´d like to hear comments/suggestions from as many as possible people on these options to have a good base to decide what´s best for the community! Thanks, Seppoman

Playback of 21 stereo tracks, 512 MB RAM, hard disk? Without an embedded PC and/or massive DSP power, no way. Seppoman

Actually, dB is neither a linear nor an absolute unit ;) And the translation of the fader movement to actual dB scale is not linear even on analog consoles. People seem to feel that it is more important to be able to adjust levels precisely in the +10 to -10 dB range than between -60 and -80dB. There´s also different max. values on different consoles (and DAWs), so even if the progression of the scale follows a rule, the 0dB mark can´t be at the same spot for programs using +6dB and +12dB as a max. amplification. Of course this is kind of annoying for HUI usage, so it would be a wise idea for the audio software industry to find some common standard for this... Seppoman

No problem, I know that state ;) I also recommend using a DINx4 PCB - it´s just 5 Euros and especially if you´re a newbie saves your day. Then I noticed that you haven´t listed the extra parts needed when using the Commodore PSU: http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf Another advice: A new version of the SID software is under development atm. and this will require a newer PIC, the 18F4685. So better buy this one instead of the 452. There´s also a current version of the software for the 4685, so with this you can start right now and update later without having to buy a new chip. Seppoman

You need a bit more patience, man! You´ve just registered to this forum yesterday, your first post is about 24 hours old! Two persons have already tried to help you, so what do you expect? Do you think insulting the general public here will get you more answers in less than 24 hours next time??? And by the way: Your list is ok. Seppoman

Dafür ist wohl das Einfachste ein nicht zu dünner isolierter einadriger Draht (keine Litze). Stück abschneiden, abisolieren, fertig :)

Thanks :) The output stage is quite the same as on the old AOUT. I made dozens of OpAmp drawings and had some headache, and in the end I came up with no better solution. But the old AOUT is tested and found working well, so there´s no need to reinvent the wheel :) The bipolar option is also similar to the old version. Just no trimpots anymore, because the AD5392 can be trimmed via software. With 1% resistors, there will be an offset of around 20 mV that can be corrected via software. This way the option can be included on the board without wasting much space for another 8 trimpots :) About rendering: There´s an ULP script for Eagle that is called Eagle3D. It creates PovRay files. Seppoman

Was meinst Du denn mit "Labortestboards"? Drahtbrücken macht man einfach aus abgeschnittenen Bauteilbeinchen. Wenn die Distanz größer wird nimmt man eben ein Stück Draht. Fertig kaufen kann man sowas glaube ich nicht. Seppoman

Hi guys, just a little teaser: ;D The board size is the MBHP-standard 8x6 cm. All the resistors in the upper half can be left out if bipolar operation is not needed. The rendering of the trimpots is a bit off, but I´m no 3D expert ;) Seppoman

I´m sure that in the meantime there are technically (and probably also musically) better affordable DACs than the Camtech. After all, this unit is around ten years old which is a millenium in digital technology. I was not really following the developments of the last years, as I´m quite satisfied with the sound of my stereo (B&W Preference 6 speakers, Camtech V102 amp, Thorens/SME/Ortofon turntable etc., I´ve spent a lot of money into this over the years :)). What I wanted to say is: For CD playback, datasheet specs are only perhaps one third of what makes a perfect listening experience. In the last ten years, you nearly could´t buy any digital equipment anymore (above some sensible amount of money) that has technical specs which would tell you it doesn´t sound good. Still there are units that sound "ok" and some that sound really great. I can´t judge how much knowledge and taste Mr. Beis has in the remaining two thirds. Seppoman