Spectral DMA 150 Upgrade

[ack]

OK you just eclipsed us in the video department as well LOL. I just happen to have a good Sony 4K camcorder I know interfet and it will be interesting to see what you come up with.

Regarding transports, the mechanical parts are one thing; but the electronics are obviously a big part of this. Just comparing my ex 3000 vs the current 3000SL is proof in the pudding, with the latter offering much lower noise, thus more vividness.

Enjoy the music!

 

[Adimon]

@ Jon Q or other

My Spectral power amplifier gets quite warm.

The cover of my amplifier has no cooling holes !?

Now I want to lift the hood slightly but then I need longer screws.

The original screws are non-metric types (Europe).

Do you now know what types of screws these are?

And where I can order them.

 

[Jon Q]

@ Jon Q or other

My Spectral power amplifier gets quite warm.

The cover of my amplifier has no cooling holes !?

Now I want to lift the hood slightly but then I need longer screws.

The original screws are non-metric types (Europe).

Do you now know what types of screws these are?

And where I can order them.

Hi
see link...
https://www.tme.eu/en/katalog/bolts_100316/?art=B4X45/BN611&page=21

 

[Adimon]

Hi
see link...
https://www.tme.eu/en/katalog/bolts_100316/?art=B4X45/BN611&page=21

Thx a lot.
The one you advice is hex 3mm screw (i did try a din metric m3 that does not fit).
I'm not familiar with these different types:-(


The one below in (l =20) is does the job?

 

[Jon Q]

Thx a lot.
The one you advice is hex 3mm screw (i did try a din metric m3 that does not fit).
I'm not familiar with these different types:-(


The one below in (l =20) is does the job?
View attachment 70722

Hi Adimon

I'm sorry, I sent the link address wrong. The screws for Spectral DMA 150, l ordered from ebay, the supplier noted below. It has several models with different length and diameter.

https://www.ebay.com/itm/Flat-Head-...732564?hash=item23b709de14:g:i8UAAOSwAdhcc2S8


For cover, I use the srews has a diameter of 1/8. (see picture)

jon

 

[dan31]

Are those control knobs from a DMC-20 in that picture?

 

[Adimon]

Hi Adimon

I'm sorry, I sent the link address wrong. The screws for Spectral DMA 150, l ordered from ebay, the supplier noted below. It has several models with different length and diameter.

https://www.ebay.com/itm/Flat-Head-...732564?hash=item23b709de14:g:i8UAAOSwAdhcc2S8


For cover, I use the srews has a diameter of 1/8. (see picture)

jon

Hi Jon,

I already ordered them on ebay.
Thx for the link

 

[Jon Q]

Are those control knobs from a DMC-20 in that picture?

Hi Dan
No, but they are same. They are from my recent purchase, Spectral DMC-10.
After a lot of choice and searching, I bought this model. Of the three models DMC-10 , my choice was Delta, I also liked the serie gamma. At the moment I am doing a complete up-grade, the big change is its phono stage, very identical to the DMC-20.
The DMC-20, I liked the phono section, but the line section doesn't respond to what I'm looking for. This was the reason for choosing DMC-10 (delta)

 

[Adimon]

Hi Jon,
Received the bolts today but unfortunately they don't fit either.
I don't know which type I do need.
The thread pitch is greater than 1/8

Any idea what the exact type it could be.

 

[Jon Q]

Hi Jon,
Received the bolts today but unfortunately they don't fit either.
I don't know which type I do need.
The thread pitch is greater than 1/8

Any idea what the exact type it could be.

strange, I don't have this problem. In diameter or thread pitch. only the difference is 10.9 steel, black color and longer length

 

[timztunz]

strange, I don't have this problem. In diameter or thread pitch. only the difference is 10.9 steel, black color and longer length

It could just be the photo but these two screws don’t seem to have the same angle of pitch to me.

 

[domenico80]

Great and excellent work, of competence, congratulations Jon.
Those diode bridges too 'I struggle to understand the meaning in such a device, but if they have used them, okay as okay replace them.
We made an almost identical ending, but with a dual fet emitter after the input stage, very interesting.
I see that for the drivers BJTs have been used or are standard and not Mosfets: we have used the IRF 610 and 9610.
We also stabilized the final power stage in voltage, still interesting and interesting the 170 microvolts at the output.
We also tried a switching power supply instead of the linear: let's get out of switching, a Hypex, for now, and then re-stabilize with the linear. We managed to have only one capacitor on the lines and we opted for a 10 micro SMD tantalum, parallel series for voltages.
The switching, which does not radiate, does not vibrate, is stabilized on its own and we placed it centimeters from the linear input: switching in a necessary, even if not necessary, Faraday cage

 

[domenico80]

Hi Dan
No, but they are same. They are from my recent purchase, Spectral DMC-10.
After a lot of choice and searching, I bought this model. Of the three models DMC-10 , my choice was Delta, I also liked the serie gamma. At the moment I am doing a complete up-grade, the big change is its phono stage, very identical to the DMC-20.
The DMC-20, I liked the phono section, but the line section doesn't respond to what I'm looking for. This was the reason for choosing DMC-10 (delta)

hi ..... if I have read correctly the same changes made to the DMA150 power amp are not suitable or are they not worth being made even at the pre 20?

 

[Jon Q]

hi ..... if I have read correctly the same changes made to the DMA150 power amp are not suitable or are they not worth being made even at the pre 20?

Hi
The DMC20 is very transparent and fast, but "chopped at high frequencies", it is not neutral for my personal taste, I prefer neutrality and speed. Making an update also implies the replacement of transistors, the DMC20 uses chips of 4 transistors in one. This is where I have the problem, there are not many alternatives on the market.
But the phono board is very good, and it gets better with an update, using good components.

After that, I heard more spectral preamplifiers, my final choice was the DMC 10, (series Delta). It was not easy to find in the market, until I found one in Denmark, sorry to have some scratches on the front panel.

The upgrade implies a series of situations, capacitor, RCA connectors, resistors, addition of an XRL output, gain option on the phono stage by jumpers.
The RIAA line possibly, I will do the same as the DMC20, (RIAA passive / active). The DMC10 board, "Delta series", allows you to do this without changing the tracks.

jon

 

[domenico80]

I agree.
That 10 series is very good.
I don't know the scheme of THAT 10, but of the first 10 and in what you describe it seems have used duals for the second differential and relative mirror . In any case, the story of the quadrial on the 20 and the 150 is true, a nice mess even if comfortable for Spectral.
I see that the scheme of 20 has changed and after the input dual fet there seems to be either an emitter or a vascode like Goldmund .... I would say a cascode because I see a band limitation cap.
Even the outputs of 20 seem no longer to mosfet, but to Bjt in TO 220, as in 150.
We have, for the pre, only the dual input fet, no cascode, no emitter and it is fed with a shunt, a beautiful object, very sensitive to the chosen resistances and to be left always on.
Instead the final after the cascode, we have an emitter with 209 that does not load me too much the second differential. We too have chosen the way of fine tuning for each power mosfet, so we don't select them, doubling differential and driver, drivers that are the 610 and 9610

 

[Jon Q]

..."Even the outputs of 20 seem no longer to mosfet, but to Bjt in TO 220, "...

The DMC20 uses mosfet on the output stage , VP 0109 / VN 0109 package TO-220, in the DMC10 update, I also opted for these output transistors, line amplifier section and phono stage, but package TO-92.
I personally am not a fan of the IRF610 / IRF9160 mosfets, but that is just my opinion.

 

[domenico80]

in the pre DMC 10, at least what I remember, then I do not know if there have been re-editions and changes, at the output they used 2 mosfets P and 1 mosfet N I think for the problems that at the time had the P mosfets in TO 220.
We haven't tried the VP mosfets, but the 610 and partner are very satisfactory. I read that VPs have less gate capabilities, but higher output impedance.
Do you think VPs might be worth trying?
I don't like those quad chips either because, if polarized like the 5551 and 5401, they should dissipate around 900mw.
PS
Just seen this morning that the IFN 411, replacing the 2N5566 has doubled in price: € 20 + VAT

 

[domenico80]

The DMC20 uses mosfet on the output stage , VP 0109 / VN 0109 package TO-220, in the DMC10 update, I also opted for these output transistors, line amplifier section and phono stage, but package TO-92.
I personally am not a fan of the IRF610 / IRF9160 mosfets, but that is just my opinion.

respectfully, but I think one problem with the 150 Spectral is those MPQ series chips.
We have returned, after several tests, to the old 5551 and 5401

 

[kennyb123]

I have a 150 Mk2 and was wondering about the fuse I spotted on the board on the right hand side. Does anyone know what this protects? I’m just wondering if anything could be gained by swapping in a better fuse.

 

[Jon Q]

I have a 150 Mk2 and was wondering about the fuse I spotted on the board on the right hand side. Does anyone know what this protects? I’m just wondering if anything could be gained by swapping in a better fuse.

View attachment 72159

This fuse is the protection of transformer located next to it. That transformer is the power supply for protection circuit.
Change the fuse? yes, I had a positive result, see also the guidance that the manufacturer recommends