Simplistic NJFET RIAA

[nicoch58]

EIFL EXPORT HOME PAGE,vacuum tube,valve,amplifier,speaker,mail-order sales 307$ incluse shipping ,serius seller

 

[RCruz]

Wild looking amps ....

And you found the Denon carts

 

[merlin el mago]

EIFL EXPORT HOME PAGE,vacuum tube,valve,amplifier,speaker,mail-order sales 307$ incluse shipping ,serius seller

Grazie 1.000, looking the web I see Koetsu cartridges entry level like Black & Rosewood Standard for JPY 75,000 aprox. 580€00!!!!! if it's correct surely I buy one, but seems a service to rebuild or repair.

Ciao

Merlin El Mago

 

[merlin el mago]

Seems the Denon DL-103-R likes Tonearms with high mass & mine Ekos is mid-mass

 

[Salas]

Mine is Mission 774 (ULM class) and I measured 8.5 Hz Fs with the test disc for the combo. Weird cart.

 

[nicoch58]

"but seems a service to rebuild or repair" yes !

that's why I haved buy old 10year koetsu from ebay (that work fine as is )

My suggestion is to go for Salas dl103r....

 

[merlin el mago]

Matched LSK389

Hi Salas

Finally matched the 12 pcs. LSK389 dual:

Group 1
1 IC: 1st njfet 7,42 / 2nd njfet 7,50
2 IC: 1st njfet 7,25 / 2nd njfet 7,02
3 IC: 1st njfet 7,83 / 2nd njfet 7,82
4 IC: 1st njfet 8,05 / 2nd njfet 8,24

Group 2
1 IC: 1st njfet 9,32 / 2nd njfet 9,25
2 IC: 1st njfet 9,74 / 2nd njfet 9,72
3 IC: 1st njfet 9,29 / 2nd njfet 9,28
4 IC: 1st njfet 9,23 / 2nd njfet 9,29

Group 3
1 IC: 1st njfet 10,53 / 2nd njfet 10,59
2 IC: 1st njfet 10,96 / 2nd njfet 10,97
3 IC: 1st njfet 10,54 / 2nd njfet 10,62
4 IC: 1st njfet 11,23 / 2nd njfet 11,29

3 pcs. K170GR single

1 Idss: 5,0
2 Idss: 5,2
3 Idss: 5,7

3 pcs. k170bl single
1 Idss: 7,6
2 Idss: 9,7
3 Idss: 10,24
4 Idss: 10,25

With these can I make your Simplistic NJFET RIAA? or it's necessary that I wait until I receive the batch of 100 pcs sk170 single from Spencer to match exactly Idss: 8-9?

Surely I buy the Denon DL-103R, it's a good idea to change the body & install one offered by Soundsmith, or buy both to Soundsmith so I will have the wood body installed?

An externally hosted image should be here but it was not working when we last tested it.

Merlin El Mago

 

[Salas]

Hmm...I see many interesting pairs between 9-11 in your stash. I will have to see about the MC version with a mean average of 10.5 and let you know precisely, in the next few days. Surely you can get more gain with a different B+ and some possibly altered resistor values.

 

[merlin el mago]

Thks for your help Salas

 

[nicoch58]

the R body is already non resonant ...wood can be better but....

 

[merlin el mago]

Is possible that the Denon DL-103 Standard with wood body will be better than the Denon DL-103R?

Thks for advice

 

[massimo]

The 103R has different coils (see specs) wound with high purity 6N copper. The body is similar, but internally it has a piece of damping material.

 

[merlin el mago]

Grazie Massimo, yes I know the differences between both carts, the question is: sound better the 103 Std with wooden body vs 103R version with damper inside & bound with 6n copper?

 

[Salas]

I doubt that the damping benefit is going to overcome the SNR electrical benefit of much lower Ro for virtually the same Vo importance. Mechanically its a lighter coil as well. Though I haven't had a chance to subjectively compare on a TT. Take it with a pinch of salt.

Interesting solutions to your investigation maybe:
ISOkinetik Denon 103 dl-103 aluminium body RED DL-103R bei eBay.de: Turntables (endet 19.12.09 18:53:04 MEZ)
NEW DENON DL-103R WITH MOUNTING BLOCK MOD MK2 IMPROVED bei eBay.de: Turntables (endet 14.01.10 15:05:08 MEZ)

 

[Salas]

Hi Salas

Finally matched the 12 pcs. LSK389 dual:

Group 3
1 IC: 1st njfet 10,53 / 2nd njfet 10,59
2 IC: 1st njfet 10,96 / 2nd njfet 10,97
3 IC: 1st njfet 10,54 / 2nd njfet 10,62

3 pcs. k170bl single

3 Idss: 10,24
4 Idss: 10,25

With these can I make your Simplistic NJFET RIAA?
Merlin El Mago

My idea is that those good strong LSK389 pairs should be put into action. We all get enough 2SK170BL 10-11mA pieces in small volume purchases too. So in your case you must use one chip for Q1&Q7 plus another for Q2&Q5 per channel. Your singles #3 & #4 will do Q6 per channel. C10 must be good quality, 6-16V is enough, you can subjectively try a bypass with Vishay MKP 1837 10-100nF or analogous, also. 63dB of gain is enough for low MC, else there is weak gain structure in the rest of a system. Double Jfet 1st stage and Rs bypass should keep the hiss just OK. Not champion, but normal. Especially with circa 90dB speakers. If it will work nicely for you, it may be OK for everybody. It has the advantage of simply taking out C10, by a local DIP switch even, and falling directly to 57dB for 0.5mV normal MC. Somebody can move between Low MC and normal MC carts without overhauling the phono stage. Just a new Rload value if needed, can be DIP switched too.

 

[merlin el mago]

I believe that I need 1 double lsk389 more or 2 singles k170, looking for more njfets I have sgls K170V, one Idss 10,67 & the other Idss 10,76, I suppose that can use it?

Thks again for your kind help

Merlin El Mago

 

[RCruz]

Can this be done with "normal" 2sk170bl ?

I have some in that 10.5mA range

Can this version compete with the previous 56dB 37V version if used without the bypassing EL ?
besides the higher gain and working voltage, what are the main differences ?

Is there any kind of "special" dip switch ?

 

[merlin el mago]

A this moment I don't have sk170bl because I am waiting from Spencer a batch of 100pcs to match, the reason to use other njfets is that I have available at this moment at home.

 

[merlin el mago]

Mine is Mission 774 (ULM class) and I measured 8.5 Hz Fs with the test disc for the combo. Weird cart.

What Mission 774LC arm are you using: 228mm long or 228,48mm long?

I remember mine 1st TT, was a Michel TT with a Mission 774LC Tonearm & a Sumiko Talisman MM cart.

 

[merlin el mago]

Is there any kind of "special" dip switch ?

Well I suppose that instead an internal dip swicth can be done by a external toggle switch.

I mind is to suppres C10 so instead 63dBs ultra low gain MC will be 57dBs mid gain MC, that's possibility is very good for me due to the fact that I have several MS carts ultra low gain & mid gain