Low powered SS amps for high efficiency speakers

[atharva]

Hello friends,

Hope you and your loved ones are safe.

Thanks to the lockdown the idle mind has started to imagine what-ifs . I'm using 2A3 tubes right now and am considering experimenting SS amps with my Maargas. A 300B is still on the cards but may be later.

First Watt amps were the only ones I could find. More than 15 Watts would be wasted watts and heat. The SITs are unobtainable so the F1, F3, F7 look like the best candidates. The J2 is also current production although more power. The J2 is $4K, F7 is $3K and SIT3 is $4K.

If I were to take the DIY route looks like there are 3 choices. J2 Clone, F3 and SissySIT. There seems to be not much activity on the F3 any more. The J2 clone will be expensive because of the Semisouths (still cheaper than the original J2). I don't think there is a DIY F7. BTW, I don't mind paying more for a "better amp".

Any experiences? Suggestions? Other options worth considering?

Thanks for your time and be safe.

 

[jai1611]

Another option to consider is the Firstwatt ACA amplifier. 5-6w, easy to build. I remember trying it with the old Saadhanas. Good match. There were quite a few around a few years back. See if you can borrow one locally to try out. If it works well, build one with a good power supply.

If sticking to tubes, scout for a used Gaanam integrated that Rethm used to make. Dont buy directly from the guy who used to build for them though - a lot of the quality of that amp had to with the refinement and QC Rethm ensured.

Another tube option is the Leben 300xs. Warmer sounding than the Gaanam

 

[atharva]

Keeping away from Tubes for now just to try an SS. I've been bugging Jacob to come up with a Gaanam alternative.

I'd love to try an ACA. Correct me if I'm wrong but I assume the J2/F3 etc would be much better albeit at a higher price.

 

[essrand]

What about a Sugden A21 or A21SE Signature? Good Single Ended SS amps comparable to Pass SIT. Apparently they were the SE SS amps pioneer. The distributor is a great guy to deal with also.

 

[jai1611]

I'd love to try an ACA. Correct me if I'm wrong but I assume the J2/F3 etc would be much better albeit at a higher price.

The ACA may be possible to try out. Not really possible with the other First watt options

 

[arao]

Hello friends,

Hope you and your loved ones are safe.

Thanks to the lockdown the idle mind has started to imagine what-ifs . I'm using 2A3 tubes right now and am considering experimenting SS amps with my Maargas. A 300B is still on the cards but may be later.

First Watt amps were the only ones I could find. More than 15 Watts would be wasted watts and heat. The SITs are unobtainable so the F1, F3, F7 look like the best candidates. The J2 is also current production although more power. The J2 is $4K, F7 is $3K and SIT3 is $4K.

If I were to take the DIY route looks like there are 3 choices. J2 Clone, F3 and SissySIT. There seems to be not much activity on the F3 any more. The J2 clone will be expensive because of the Semisouths (still cheaper than the original J2). I don't think there is a DIY F7. BTW, I don't mind paying more for a "better amp".

Any experiences? Suggestions? Other options worth considering?

Thanks for your time and be safe.

I too have Maargas (2019 version). Driven by 300b monoblocks. What 2A3 amp are you using currently?

 

[AVM]

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Regards

 

[atharva]

Thanks for the suggestion on the Sugden. Will definitely take a look. Contact info of dealer in India?

@arao, I'm using Lyrita 2A3 with the 4P1L pre.

 

[arj]

Atharva, you might not find it easy moving from your amp to sugden. While sugden is a step up from usual amps, I suspect the SET 2A3 has more harmonics and richness hence if you can please do try it out before you commit.
A First watt or pass labs might just be a better option than the sugden.

 

[prem]

Atharva, Sugden is not a good match with Rethm. Sugden does not have the speed, transparency and the linear bandwidth needed for the Rethm to sing. Look up First Watt SIT or a Bakoon 13R

 

[prem]

Lyrita 2a3 in its stock form is not a great match with Rethm. The Lyrita 2a3 is very well designed but you need upgraded interstage and output transformers to improve speed and bandwidth.

 

[Beast_of_burden]

Thanks for the suggestion on the Sugden. Will definitely take a look. Contact info of dealer in India?

@arao, I'm using Lyrita 2A3 with the 4P1L pre.

What you need is a new pair of output transformers. Be prepared to spend a minimum of 40k on the OPTs. The difference will be profound. I am speaking from personal experience. Most 2A3 designs are simple and similar, the key differentiators are the OPTs(resistors and capacitors matter too) and the layout/grounding scheme. Sometimes superior OPTs and sensitive speakers reveal issues related to hum.

 

[atharva]

@arj interesting.

@prem, the SITs are unobtanium. A souped up 300B is on my radar for later. Given that the J2 clone is blessed by Papa himself makes it attractive. The SissySIT guy has compared it with a SIT3 and says while not exactly same it is pretty darn close.

 

[atharva]

@Beast_of_burden , yes a souped up tube is on the cards for later. Just experimenting with an SS.

 

[prem]

300b amp is not an ideal match with the Rethm. It doesn’t play to its strengths. With Rethm, the trick is you need to play to it’s strengths. If you try to use an amp to cover up its weakness, it will not work. A J2 should be ok.

FYI, Pass recommended his F3 for the older Rethms.

 

[Kannan]

The 1st version of AmpCamp which I am also using is a musical amplifier, but technically in terms of specs like noise floor etc., quite bad.
But the latest version offers balanced stage with around 12-15 watt single ended, and could be an improvement over the specs aswell.

But I think Pass's FW offerings or their clones therein could be a better bet.

There is also a Vfet design from Mr. Pass if you can find the original MOSFETs, it should make a very good sounding amp to build.

 

[Beast_of_burden]

300b amp is not an ideal match with the Rethm. It doesn’t play to its strengths. With Rethm, the trick is you need to play to it’s strengths. If you try to use an amp to cover up its weakness, it will not work. A J2 should be ok.

This is an interesting insight, please elaborate why a 300B SET with 8 watts might not work with a 2A3 SET with 3.5 watts. 300B and 2A3 are different and have their devotees. I have a sneaking suspicion 300B devotees have never heard a 2A3 and vice versa. You can probably guess where my preferences lie, however I don't have much exposure to 300B and its supposed to be chameleon like depending on implementation.

What's the character of the Rethm that doesn't quite jell with a 300B?

 

[prem]

I will try and answer it as best as I can. I have heard the Rethms with a variety of tube amps from a 45 to a 2a3 to a 300 to a 845 to a 6c33. A 300 tube is not as agile or quick as a 2a3 which in turn loses out to a 45 tube when it comes to speed and agility. Rethm likes amps which are very agile. Unfortunately a 1.5 watt 45 tube amp for some reason doesn’t work too well with Rethm. The 2a3 which is 3.5 watter works perfect. The 50 tube which is the grandfather of the 45 tube will probably work even better with a Rethm. Similarly there will be speakers which prefer a 300 over a 2a3. The synergy between amp and speaker is more critical. On even higher sensitivity super expensive speakers like Pnoe, the 45 or 46 tube amp work the best. And that’s just a 1.5 watter. A 45 tube amp is different sounding from a 2a3 tube amp which is very different sounding from a 300 tube amp. Each SET tube sounds very very different from each other unlike pentodes where there is a little more similarity.

 

[jenson]

theres an f5 v2 clone with forum member in Pune...i guess it would give you a hint of what sound signature to expect...ofcourse it would not be fair to compare it with first watt product...but it's a genuinely good build.

as many members have suggested, changing OPT's on Lyrita could be another option...i too have the lyrita 2a3 + dht pre and the lowther version saadhana's. quite tempted to upgrade the OPT's...

 

[Kushanava]

@atharva : I am in the same boat as yours. Trying to get a matching AMP for my Rethm.
My personal experience tells me , we need a fuller sounding amp. I have used sugden a21se , leben , Zotl so far.
Out of these 3 i preferred the Sugden for its clarity , but like Prem mentioned , its still not the right match as it sounded lean .
Leben was smoother , but robbed the dynamics and sounded flat. MicroZotl (1 W) was the most transparent but rethm wanted a little bit more power.

Currently I am content with a very basic amp ( Quinpu from China) . I just got it as a stop gap amp , a 16W amp with a tube pre and class AB amp.
Its very good amplifier that i am not in a hurry to change. It was a real surprise. Its not the most revealing amp , but somehow it sounds more musical than the other amps with the Rethms. I am attempting to look at the source now rather than investing on the amp straight away.
What source are you using ?