IslandPink wrote:Good evening .
Thought I'd just share this, might be of interest .
It is a partner to the other thread, in the speaker section :
I've set myself a target of bringing something useful along to Owston next time we meet. I reckon I can get 1-off mid-bass horn and a HF horn into the car, but I'd better have a suitable ( portable ) amp available to drive it.
The amp will have two or more channels , each with a suitable filter slope incorporated . I shall start off with two channels ; if I can fit the filter bit for the low bass ( tapped horn ) into the box, that will be attempted too .
I have just ordered one of the bigger Hammond wood-frame-aluminium-top-plate boxes from Phil at Bluebell Audio .
Here is the rough idea of the circuit . The bit that needs development is the 'enhanced' cathode-follower bit .
IslandPink,
Here a replay to you initial post of the thread. I did look at your schematic of Milq Lite, here is a few comments.
I do not know what the input state does in there and what phone level input you are willing to implement. You never will be able any sensible RIAA with one state even if you have very high cartridge output. Even if you come up with some crazy solutions then the gain that you get with one state would not be enough to flood Milq's input stage. You will be losing 20dB 9in RIAA EQ, it will be juts no gain with one state even if you go with pentodes. Now, the Milq input stage is 6E5/6P which is a perfect tube for high voltage line level application. It has 4.5V bias that assures that no cathode feedback the input tube will not go to A2. It is only very few DACs will put out 4V-5V at 0dB digital but most of front end never will do more 2V. Having high bias and ability to accommodate high input voltage the 6E5/6P can swing 33dB and to push 35mA - enough to driver anything that do not resist with grid current. That was the whole idea if Milq - two stages only, deep A1 and no feedback. If you wiling use my 6E5/6P then use the Milq-style bias with gas tubes and grid resistor - it is essential for this tube. You might use any other tube you wish but if you want to call it Milq then use my bias as it define the 80% of the amp's sound. So, I think it will take care about the question mark you have in the driver cathode...
Ok, let see more. The capacitive coupling in MF channel. - I find that it did not work for me unless you go with dialectic-free capacitors and I did in phonostage. However, with .001u it will be hard to do. So, go with LR filtration on driver grid and flip the MF to direct coupling floating everything on PS. The 6E5/6P is VERY stage tube and you will not have any problem to drive IDHT grid with it.
The use of 2A3 type tube to drive Fane is questionable. I do not know what horn you use and what size of your room but you might not have power to do it. I would like you to have more power but then you enter into a totally different subject as to use different output tubes in DSET application is complex and would require some intricate harmonic dancing during output state loading. It not always works however.
There are few other things that I do not like in there but all together if I were you then I would not do anything in DASE at this point. Get one SET; make it perform with your acoustic system up the level that you like with passive filtration. Then run prototypes of that SET that you know with individual channels. It is very good to make a maket of let say Milq or any other amp the you want, juts fully working model on a table with no box and then play with applying it to all channels. With some experience it is possible to visualize it conceptually just on paper but, trust me, you do want to get THAT experience on your own. Also, I absolutely assure you that during your DSET experiments you will change a lot your opinions about your own original design idea and objectives.
