A new relationship

[DaveyF]

Well, I am going to take Christian’s advice ( thank you Rockitman) and have decided to keep my JR model 8t as a back-up amp.
I think it is nice to have the ability to go ss when I need to able to hear a different approach.

 

[morricab]

After many years of enjoying a piece of gear, I have decided to have a new relationship!

Some of you may know that I have used and enjoyed the Rowland model 8 for decades. Last year, I had Jeff modify this amp and bring it up to the last and best spec. The amp came back to me and was certainly better in the resolution department and in its ability to plumb the depths. I figured I would keep this amp forever.

A few years ago, I had the opportunity to acquire an amp that was high on my want list, but very hard to source in great condition...the ARC D70Mk2. This tube amp changed my perspective of amps...and wowed me with its tube midrange purity and bass slam!

So last week when an opportunity presented itself, I found myself the new owner of an amp that I thought I would not be able to acquire....


The new amp, still to come, is the Jadis JA 30Mk2...the latest in a long line of Jadis amps that are hand made in France. This amp utilizes the new KT150's and will replace my Jeff Rowland!

I'm a little nervous about breaking up my relationship with my old love, but I think the new girl in town should be a nice change for me....

Those old ARC amps had huge output transformers...the same cannot be said for the current ones...I am not surprised you liked the sound of the old ARC amp.

 

[DaveyF]

Those old ARC amps had huge output transformers...the same cannot be said for the current ones...I am not surprised you liked the sound of the old ARC amp.

That is exactly right. The ARC D70Mk2 is an amp that i am going to probably regret selling; however, one can only use so many amps...and the Jadis is superior to the ARC. I think at the time, WZJ hit one out of the park with this amp, for it to stand today and still be an awesome sounding piece says a lot. I would love to hear the M100's, they must be really something as well.

 

[KeithR]

That is exactly right. The ARC D70Mk2 is an amp that i am going to probably regret selling; however, one can only use so many amps...and the Jadis is superior to the ARC. I think at the time, WZJ hit one out of the park with this amp, for it to stand today and still be an awesome sounding piece says a lot. I would love to hear the M100's, they must be really something as well.

The Ref75SE is quite the superior amp to the D70.

 

[DaveyF]

The Ref75SE is quite the superior amp to the D70.

We may very well get to check that theory once I have the amp at the dealer that is going to handle the sale for me. Since they are an ARC dealer, we may be able to do an 'AB'. I wouldn't be so sure that the Ref 75SE will survive this 'AB'....although the fact that it now uses the KT150's is certainly very much in its favor. However, the little D70Mk2 hits way above its pay grade...have you ever heard one?

 

[RogerD]

Looks like you have the best of both worlds...great tubes and SS. Stepping up to mono blocks I think is well worth it,especially if the system is up to par. Is it possible to bi amp in your system...might not be needed though. In my experience good SS amplification is the way to go for the LF range. Congrats Davey....enjoy!

 

[andromedaaudio]

congrats

 

[DaveyF]

Looks like you have the best of both worlds...great tubes and SS. Stepping up to mono blocks I think is well worth it,especially if the system is up to par. Is it possible to bi amp in your system...might not be needed though. In my experience good SS amplification is the way to go for the LF range. Congrats Davey....enjoy!

Thanks, Roger. Your bi-amping idea is an interesting one. I suppose I could use the Rowland to drive the mid/woofers of the GH's and the Jadis to just drive the tweets. The speakers are bi-wireable, although I'm not sure the x-over would allow me to do this??? Anyway it's a thought. For now, i'm primarily going to use the Jadis as the main amp.

 

[Audiocrack]

Played many years ago with a Cat preamp and Jadis JA 80 combination together with the Genesis 200 loudspeakers. Have fond memories of this set up and I am not surprised at all you love the CAT/Jadis combination. Have not heard the new Jadis configuration with the KT150 valves but I am sure they sound better than my old Jadis 80 with KT88 tubes. I am furthermore of the opinion that the lower powered models - JA 30 and JA 80 - are the real honies in the Jadis (power) amp line. So in short, very good choice and hope wou will love it for many years to come.

 

[andromedaaudio]

It looks like it , you have a biwiring /biamping post , if you take the bridge away , you should be able to drive the tw /mid woofer seperately , you can always contact SF for the best solution.
Plus you need a gain knob for both amps to adjust spl s

Just make sure you have Always red and black connected (plus minus ) on each seperate post no shortcuts

 

[Sablon Audio]

Plus you need a gain knob for both amps to adjust spl s

Matching the gain is an important aspect obtaining a musically coherent outcome.

 

[andromedaaudio]

You dont want the tweeter playing 4 db louder then the midwoofer or vice versa, each( power)amp has different gain
You could adjust that by ear off course , you could also hold an spl meter lets say 1,5 meter in front of the of the speaker ( height mid speaker ) and take a s spl measurement , if the woofer puts out the same spl as the tw its about right, you have to disconnect the tw if you want to measure the woofer off course and vice versa
Having the mid woofer play a bit little bit louder ususually is more pleasing then the other way around

 

[DaveyF]

Thanks guys. There is no way to separately adjust the gain with each amp. Plus, I'm not sure how this could be accomplished. The x-over for the speakers is built into the speakers, so I guess I would somehow have to bypass this?? Not something I'm willing to do.

 

[DaveyF]

Played many years ago with a Cat preamp and Jadis JA 80 combination together with the Genesis 200 loudspeakers. Have fond memories of this set up and I am not surprised at all you love the CAT/Jadis combination. Have not heard the new Jadis configuration with the KT150 valves but I am sure they sound better than my old Jadis 80 with KT88 tubes. I am furthermore of the opinion that the lower powered models - JA 30 and JA 80 - are the real honies in the Jadis (power) amp line. So in short, very good choice and hope wou will love it for many years to come.

Thank you. I am very impressed with the new KT150's in this design. The increase in resolution is amazing. Until recently, i had not considered Jadis as a viable candidate, but a local a'phile had heard the new Mk 2 and was bowled over. On his recommendation and then later others, I looked again at the line and came to pretty much the same conclusion as you...that the 30 and 80 are the sweet spot. Since I prefer fewer tubes and could get away with 45 watts/ch, the JA30Mk2 became the solution. If you have a chance to hear this amp, I'm sure you would be as impressed as I am.

 

[andromedaaudio]

If a parallel X over is used , which is common , then removing the short cut bar between the Plus binding posts and neg bindingpost respectively , actually seperates the tw and midwoofer all together in the X over
This can be easily checked , remove the shortcut plates(wires in other cases ) , and connect one amp only to the top (usually marked by tw ) now you should only hear the tw , mind you do this by the volume knob turned down and turn slowly up .
Same can be done for the bottom section usually marked by mid (mid woofer)

 

[DaveyF]

If a parallel X over is used , which is common , then removing the short cut bar between the Plus binding posts and neg bindingpost respectively , actually seperates the tw and midwoofer all together in the X over
This can be easily checked , remove the shortcut plate , and connect one amp only to the top now you should only hear the tw , mind you do this by turning the volume knob down and turn slowly up .
Same can be done for the bottom section usually marked by mid (mid woofer)

This is exactly what happens..as I run a bi-wire set up currently. The tweeter is definitely separate from the mid/woofer. However, I believe the problem with matching the two very different amps remains--in regards to their gain structure, and matching of same.

 

[andromedaaudio]

Yes .

But i believe your Cat pre amp has two main amp outputs , mine has , if you could find two power amps with the same gain , youd might have a good situation , if you have two poweramps with a slight different gain putting the one with the higher gain on the mid woofer section might be useable/ acceptable , mind you always try this with the volume down and slowly turn it up

PS corrected the cat pre has off course amp outputs not speaker outputs

Ps While connecting the amps speakers Always with power off

 

[DaveyF]

interesting, although that is the problem...two amps with the same gain structure. In this case, i am pretty certain that the Rowland and the Jadis have very different gain structures. Interestingly, I think the new Jadis has more punch than even the nearly five times more powerful Rowland!! Why, because the Jadis transformers are enormous and have more reserve than the Rowland. BTW, i don't use the GH's for much in the bass area...as I utilize two REL subwoofers with their own amps built in. This enables the GH's to basically just have to deal with the mids and highs...which is where the Jadis also shines.

 

[andromedaaudio]

I know they are very important , one reason i use the cat poweramp which has the largest transformers / capacitator banks ive see yet on a power amp .
If i turn the volume really loud with a action movie , ( which i cannot often because of the neighbours ) you actually get the same feeeling/ exitement as in a real situation just sheer energy/ force

 

[DaveyF]

This is the reason I am so very impressed with the new Jadis line...not only are they using one of the best transformers around, they are now also utilizing the new KT150's. A Killer combo. CAT amps have always been superb based on their excellent trannies...I would expect that Ken will utilizing the KT150's a lot more as well in the future.