Beyond that Blue stock is gone as far as I know, the differences are that Blue is 2 Oz plated through & top pads, takes 4 7.5mm or 10mm psu caps, has option for TO-220 diodes or small ones, has space for big set resistors and largish size film caps for bypassing the Leds Vref. It was a special edition of the Hypno. Geared better towards the hot rod and film cap proven mods. Any Black Mez or Hypno can be run hot or bypassed with plastic but were not made for that, hence not so comfortable. Any new Mez run will be 2 Oz copper too though.
can the holes on the Mez accept the leads for the to-220 diodes are do they have to be enlarged at bit to fit? also, how about the larger 3A (like OnSemi MBR3100) axial diodes?
they don't need to be enlarged. They wont fit all the way in I guess like a resistor, but it works, assuming your using new ones.
IXYS TO-220's fit, as well as MUR860 and MSR860's, from my use.
Hage not tried any above 1A axials. sorry.
Glad to see the Mez will be available again. It seems somewhat odd to keep the PCB like it is now when the Hypnotize got a revision !?!?
If there will be a slight change maybe the following things could be implemented:
- add pads for a 0.1 uF cap at the output of the 7812. It is needed !
- 2 x 0.1 uF 5 mm pitch caps could be added between the big filter caps ( in parallel with the big caps).
- the pads for the LED could be enlargened so that a connector can be used instead of a LED straight on the PCB.
- the pads for the Alps blue could be somewhat larger.
If there will be a slight change maybe the following things could be implemented:
- add pads for a 0.1 uF cap at the output of the 7812. It is needed !
- 2 x 0.1 uF 5 mm pitch caps could be added between the big filter caps ( in parallel with the big caps).
- the pads for the LED could be enlargened so that a connector can be used instead of a LED straight on the PCB.
- the pads for the Alps blue could be somewhat larger.
Last edited:
Regarding the Alps Blue pads...Do DIYAudioers really use an Alps Blue with this circuit?
Surely most of the posters are fanatical about attaining the best sound (hence making the DCB1 rather than B1, to eliminate caps) that I imagine very few of them indeed will use a normal carbon pot with this DCB1. Surely for most, these are merely pads to connect wires to a Lightspeed or stepped attenuator or whatever, no? It's helpful to keep the layout in the same pot pattern, so that it's not confusing.
They do, at least some 
For those that are allergic to Alps RK27 there is the Hypnotize. I can live with RK27, certainly when compared to even the best digital potentiometer chips. But a conductive plastic type potentiometer can also be used with the same pads. So there is some room for experimentation. If one wants to experiment even more the Hypnotize is the best choice. A Lightspeed combined with the Hypnotize seems a good combo although I read some posts about very nasty hum interfering the circuit.
There is no comparison between the original B1 and the DCB1/Mezmerize/Hypnotize, regardless of what potentiometer one uses. Omitting the 4 expensive caps is a very good sonical solution and it is cheaper so this is a no brainer. BTW the original B1 uses 2 mono carbon potentiometers, has no muting relay, has 4 caps that are in series with the sources output caps and the power amps input caps and it has only 2 inputs. IMO this project only resembles the original circuit with the 2 JFETS and for the rest supersedes it with a margin. Just take a look at the shunt supplies.
For those that are allergic to Alps RK27 there is the Hypnotize. I can live with RK27, certainly when compared to even the best digital potentiometer chips. But a conductive plastic type potentiometer can also be used with the same pads. So there is some room for experimentation. If one wants to experiment even more the Hypnotize is the best choice. A Lightspeed combined with the Hypnotize seems a good combo although I read some posts about very nasty hum interfering the circuit. There is no comparison between the original B1 and the DCB1/Mezmerize/Hypnotize, regardless of what potentiometer one uses. Omitting the 4 expensive caps is a very good sonical solution and it is cheaper so this is a no brainer. BTW the original B1 uses 2 mono carbon potentiometers, has no muting relay, has 4 caps that are in series with the sources output caps and the power amps input caps and it has only 2 inputs. IMO this project only resembles the original circuit with the 2 JFETS and for the rest supersedes it with a margin. Just take a look at the shunt supplies.
Last edited:
you might be able to use the 24V relays, as they will typically pull in at ~80% the rated voltage, but you will need to use modify the 7812 regulator circuits (i'd use LM317 with suitable ref divider network) to output a higher voltage (~20V) and use a 2x15V (or high runing "2x12V" r-core transformer) to get at least 23V at the LM317 regulator input. maybe not worth it unless you have a lot of the 24V tQ2 relays are building a bunch of mez boards.
on second thought, with 2x15V transformer, you should be able to skip the regulator, but may need to tweak the delay drive circuits.
Anto:
you're welcome. as i mentioned in the second post, with 2x15V transformer, you can omit and jumper over the 7812 regulator, and adjust the other r & c values in the muting circuit. if i understand the circuit correctly, one bc548 is used with b-e junction in reverse avalanche mode...
Hi Tincanear,
I will build only 2 mesmerize boards and I have not knowledge to make right change in this circuit parts so... I will buy some 12 v relais.
Using 12V relays on 15V to "ensure fast and reliable closing" is a remarkable approach. Those 12V relays are designed to work on 12V with a margin on the lower and on the upper side. They already pick up at 9V and should be reliable at 12V as that is... eh the voltage they're designed for. They indeed pick up marginally faster (0,3 ms) at 15V but who needs that in this application and is the difference noticeable ? Please let us use components as they're intended to be used. Please realize that unexperienced builders might get wrong impressions of such examples.
http://pewa.panasonic.com/pcsd/product/sign/pdf/mech_eng_tq.pdf
About the transformer: I use a 2 x 12V 5VA toroid with no problems whatsoever and 12V relays. Result is a Mezmerize that is very small, reliable, cool and green. It gives 2 x 14V AC with this load and I have more than 8V voltage drop across the shunt supplies. I dare to say that it is the smallest Mezmerize on the planet
http://pewa.panasonic.com/pcsd/product/sign/pdf/mech_eng_tq.pdf
About the transformer: I use a 2 x 12V 5VA toroid with no problems whatsoever and 12V relays. Result is a Mezmerize that is very small, reliable, cool and green. It gives 2 x 14V AC with this load and I have more than 8V voltage drop across the shunt supplies. I dare to say that it is the smallest Mezmerize on the planet
Last edited:
and if you were following my posts you will find that I used the resistor location that reduces the continuous current to the active relay to much less than 12Vdc.
The standard circuit charges up the 100uF to 12V and uses this to fire the relay quickly. When the charge is used up, the emf of the supply and the series resistor sets the current/voltage delivered to the active relay coil.
The 12V regulator is used with 5V relay. Is that also a remarkable approach? Where is your comment about that?
Learn to interpret what is given out.
Hi Andrew, I don't have the time to follow all your posts. The info given in the last post seemed remarkable to me. With the standard values all works just fine. The relays already pick up at 9V coil voltage and they will hold to pretty low voltages too when they are fired up. Don't feel offended please.
To defend something with a counter argument is a bit weak. Nevertheless, as I commented various times before using 5V relays with a 12V reg and series resistors is not a good approach either. I strongly recommended Salas to advise to use 12V relays as you can read yourself in my posts. So your remark: "The 12V regulator is used with 5V relay." is not fully right. In the beginning of this project 5V relays were chosen for various reasons. This was changed but then some members already had bought the 5V versions. That is why they still are mentioned and the PCB has the possibility for dumping resistors. The general rule of course is to buy 12V versions as will be done now in a group buy.
I always try to learn to interprete what is given out (which is an art itself when speaking or writing with technicians) but then the posts themselves have to be complete too. This is an international forum in which post are written in english. There is more reason to give details than when only native speakers are reading the posts. "I used a 15V reg to feed the 12V relays to ensure fast and reliable closing." is not enough information. Secondly one can't assume that everybody reads all posts as this would then be a very time consuming hobby !
To defend something with a counter argument is a bit weak. Nevertheless, as I commented various times before using 5V relays with a 12V reg and series resistors is not a good approach either. I strongly recommended Salas to advise to use 12V relays as you can read yourself in my posts. So your remark: "The 12V regulator is used with 5V relay." is not fully right. In the beginning of this project 5V relays were chosen for various reasons. This was changed but then some members already had bought the 5V versions. That is why they still are mentioned and the PCB has the possibility for dumping resistors. The general rule of course is to buy 12V versions as will be done now in a group buy.
I always try to learn to interprete what is given out (which is an art itself when speaking or writing with technicians) but then the posts themselves have to be complete too. This is an international forum in which post are written in english. There is more reason to give details than when only native speakers are reading the posts. "I used a 15V reg to feed the 12V relays to ensure fast and reliable closing." is not enough information. Secondly one can't assume that everybody reads all posts as this would then be a very time consuming hobby !
Last edited: