[DarknightDK]

Sorry if I had missed this but what's the difference between the KGSS and KGSSHV?

 

[El_Doug]

moar volts! 
 
Quote:

Sorry if I had missed this but what's the difference between the KGSS and KGSSHV?

 

 

[kevin gilmore]

1400 VPSS --> 2000 VPSS
and the current source in the 3rd stage.
And a whole bunch of newer better parts.
And a very tightly regulated power supply.

 

[DarknightDK]

Quote:

1400 VPSS --> 2000 VPSS
and the current source in the 3rd stage.
And a whole bunch of newer better parts.
And a very tightly regulated power supply.

 That's awesome!
 

 

[Tilpo]

If your β22 has speaker taps, getting a transformer like SRD7 or the Woo unit seems to be the most reasonable way to go. Lambdas are not that demanding to drive after all unlike the O2 comparatively. 

It doesn't. I would be able to put them in, but I wonder whether it requires balanced connection, since I built my Beta22 to have 2 channels, and not 4.

 

[K3cT]

No need for that. I installed them in mine and it's a 3-channel version (only the L and R channels are used for the speaker taps). 

 

[J-Pak]

Quote:

Oh, and for those wondering about the P&G, the price quoted to me a few months ago was 365$ a pop. 10k max, but they can do 20k versions. Minimum order quantity is 2. lead time is a minimum of 2 months. 

That must be for the 2-ch version? I have heard more like around $500 for a quad gang.
 
Sort of wish I bought 2 of the quad RK50 for $565

 

[sachu]

No deepak. It is for the 4 channel version.
 
Call, Manco, their US distributor. THeir 2 month lead is what threw me off.

 

[Tilpo]

No need for that. I installed them in mine and it's a 3-channel version (only the L and R channels are used for the speaker taps). 

And you can drive a lambda series headphone from that (with the needed transformer, of course)?

If that is the case, then getting a Stax rig becomes drastically more realistic.

 

[tyre]

Nevermind.

 

[milosz]

Quote:

If your β22 has speaker taps, getting a transformer like SRD7 or the Woo unit seems to be the most reasonable way to go. Lambdas are not that demanding to drive after all unlike the O2 comparatively. 

Hmmm, now THERE'S an idea.  The thing that limits the B22's power (like, for speakers) is heat dissipation, if I remember correctly.  So by "having speaker taps" I assume you mean larger heat sinks as well as binding posts.
 
As an alternative to a B22, there are a good many very good sounding low-ish power Class-A speaker amps available used for under $500 -  for example, Monarchy SM-70, N.E.W. A20, and numerous DIY Nelson Pass builds whose builders move on for some reason and sell their amps. There's also the Class-A hybrid MOSFET- EL34 tube power amp from AMC, the CVT-2030.  I've used a CVT2030, an SM70, N.E.W. A20, and a DIY  First Watt F3 clone (power JFET) all to good effect.  I rather like the CVT-2030, you get the midrange wonders of the EL34 but with a more transparent treble from the MOSFET drivers than some all-tube amps I've tried.  Any of these amps typically sell on the used market for $500 or less.  All you need is a 50K pot (or stepped attenuator if you want to get fancy) between DAC and the power amp for a level control, assuming your DAC has a reasonably low output impedance.
 
Please note that the Monarchy SM-70 is class A;  the SM-70 PRO and SM-70 PRO MK II are NOT class A, they are class AB.  Many people think the SM-70 PRO series are class A, and represent them as such when listing them for sale, but a proper Google search will show you that the "PRO" series are not class A.  The "Pro" series are good sounding amps, but I just like class A designs, especially for headphone use where not very much power is needed.

 

[Tilpo]

Hmmm, now THERE'S an idea.  The thing that limits the B22's power (like, for speakers) is heat dissipation, if I remember correctly.  So by "having speaker taps" I assume you mean larger heat sinks as well as binding posts.
 
As an alternative to a B22, there are a good many very good sounding low-ish power Class-A speaker amps available used for under $500 -  for example, Monarchy SM-70, N.E.W. A20, and numerous DIY Nelson Pass builds whose builders move on for some reason and sell their amps. There's also the Class-A hybrid MOSFET- EL34 tube power amp from AMC, the CVT-2030.  I've used a CVT2030, an SM70, N.E.W. A20, and a DIY  First Watt F3 clone (power JFET) all to good effect.  I rather like the CVT-2030, you get the midrange wonders of the EL34 but with a more transparent treble from the MOSFET drivers than some all-tube amps I've tried.  Any of these amps typically sell on the used market for $500 or less.  All you need is a 50K pot (or stepped attenuator if you want to get fancy) between DAC and the power amp for a level control, assuming your DAC has a reasonably low output impedance.
 
Please note that the Monarchy SM-70 is class A;  the SM-70 PRO and SM-70 PRO MK II are NOT class A, they are class AB.  Many people think the SM-70 PRO series are class A, and represent them as such when listing them for sale, but a proper Google search will show you that the "PRO" series are not class A.  The "Pro" series are good sounding amps, but I just like class A designs, especially for headphone use where not very much power is needed.

If the specs on STAX' website are correct, the 507 doesn't need that much power. The Beta22 can deliver 18 watts into 8 ohms.
If the transformer would be fairly efficient (>50%) it should certainly be possible to supply the 100Vrms at 145kOhm to reach 100dB. This equates to 0.08W, so to reach 115dB you would need 2.2W, which is certainly within the Beta22's possibility.

I know this is simplifying things, but I do think that the Beta22 should be able to drive them to decent loudness. Of course, I will ask people who have tried this first before doing such a large purchase. (I need to acquire a large amount of currency before I can in any case)

And if you're talking about getting a $500 amp and then a $500 transformer on top of that, I could just as well get an electrostat amplifier in the first case.


Edit: nevermind. I just saw an SRD-7 on eBay for about $200 shipped. That's actually quite affordable, and if it doesn't work well enough with the Beta22 I also have a vintage amp with plenty of power. Might not sound as good, but it would definitely suffice until I would get something better.

Won't be until many a month before I'm going to purchase anything in any case.

 

[Beefy]

I used an M3 to power some SR-Lambda (normal bias) through a SRD7-SB to near deafening levels. A B22 is substantially more powerful, and would be able to handle it without breaking a sweat.

 

[Tilpo]

I used an M3 to power some SR-Lambda (normal bias) through a SRD7-SB to near deafening levels. A B22 is substantially more powerful, and would be able to handle it without breaking a sweat.

Thank you for this clarification. I guess I'll order some speaker tabs and then I'll save up to get a 507.

At what price would you consider them a good deal? Most of the stuff I have seen up until now is $900 - $1000 which is still a bit on the expensive side.

 

[Beefy]

 
Quote:

Thank you for this clarification. I guess I'll order some speaker tabs and then I'll save up to get a 507.
At what price would you consider them a good deal? Most of the stuff I have seen up until now is $900 - $1000 which is still a bit on the expensive side.

Considering this will be your first Stax, why not shoot a bit lower and get some second hand SR-202 first?
 
It will give you a chance to make sure you are happy with the B22/transformer for driving them, and gives you plenty of scope for future upgrades.
 
Also, you might need to install a Zobel network on the speaker outputs. It helps keep the amp stable into an inductive load. Check AMB's website for details.