New Lyrita 300B SET amplifier

[Rajiv]

I already have his 2A3 power amp. So I need to know how different this one is. Wattage is not an issue for me as my speakers are highly sensitive.

Regards,
Sharad Medhavi

Hi Sharad,

The difference between the stock Lyrita 2A3 amp you have and the one Anil and a few of us have is that the driver tubes are the 45 tube. The stock amp comes with 6E5P driver tubes.

With the 45's the amp is all DHT. Viren can modify your amp if you provide the 45 tubes.
This is a custom build and an improvement to an already very good amplifier.

Regards
Rajiv

 

[prem]

Smedhavi, the 2a3 as compared to 300 would be more linear, more transparent, have better resolution, speed and micro dynamics.

The 300 would be a fatter sound with a punchier mid bass. The only 300 tube amp I have heard that has great resolution and speed is the Wavac amp but that’s exorbitantly priced. The Wavac is able to do this because it has a special proprietary designed circuit.

Otherwise the 2a3 vs 300 pretty much mirrors what Anilva mentioned.

It all comes down to what floats your boat.

Personally I would take the 2a3 sound over 300 if the speakers are up to it.

Also I prefer SET 2a3 to PP 2a3.

Most importantly, Viren designs world class amps at down to earth prices. You can’t ask for more

 

[Rajiv]

All the way DHT with 300B tube front and 45 driver stage, I think, its the "ideal" combo in every way..... may be the "end game".

Hi,

If your speakers are very efficient(think horns) and you don't listen at ear splitting levels then all DHT with 45 driver and output tubes especially the Globe 45's is in my opinion close to audio nirvana.

I biamp my Altec horns with a two stage custom made Lyrita 2A3 push pull amp using Partridge power supply chokes and Partridge OPT's for the 515B woofers, and the Lyrita all DHT amp with RCA ST 45 tubes as drivers and Cunningham globe 45 tubes for output for the Altec 288's and Pioneer HW7 tweeters.

Regards
Rajiv

 

[prem]

The good 300b tubes are very expensive, be it new production ones like EML or Elrog or the vintage ones like WE. NOS Western Electric 300 is close to USD 2500 a pair

2A3 and 45 vintage are way way cheaper.

What Rajiv is doing is interesting because he’s using the 45 only for mids and highs and a more powerful amp for the bass. Similar practice can be adopted for OB where the FRD is driven by 45 and the bass driver by a more powerful amp

 

[Rajiv]

Hi,

Interesting description of the sound of the various DHT tubes . I agree with his observations given my listening experiences (limited) to these tubes.

http://vinylsavor.blogspot.in/2014/10/the-sound-of-tube.html

Regards
Rajiv

 

[anilva]

However, driving hf mid by one tube amp and bass by another tube amp, I am clueless on the active crossovers. The ones with op-amps are insipid. Rob my FRs of the tube magic. MiniDSP ? May be, am yet to test. JFET active XO ? Too expensive..,,

You can do biamping. No need to do active crossover. Rajiv is doing just that.

 

[heliumflight]

Will 300B be able to drive Pioneer 99db speakers 5 way system? https://www.hifiengine.com/manual_library/pioneer/cs-907a.shtml

 

[anilva]

Will 300B be able to drive Pioneer 99db speakers 5 way system? https://www.hifiengine.com/manual_library/pioneer/cs-907a.shtml

99dB speaker is an efficient one. 300B should be able to drive, no problem. What you must be looking for is the tonal quality of the speaker (dependent on the drivers used and the cross over), whether it will match the 300B tube sound or not? It looks like the Pioneers were designed with a Solid State amp in mind.

 

[prem]

Heliumflight, I think a 5 way system might be too much for a 8 watt amp to handle, especially with all those crossovers

 

[Rajiv]

Am working on similar aspects.

Would be a great way to summit, starting from EL84 for mid hf and solid state for bass.

When biamping it

Please explain. Using passive crossovers?

Yes I am using passive first order crossover.

Regards
Rajiv

 

[smedhavi]

I use an active crossover, only for the woofer(<100Hz) and tweeter (>10KHz). The full-range speaker is connected directly to the Lyrita 2A3 power amp without any kind of crossover in the signal path. The Lyrita DHT pre-amp has two pre-outs. The second one goes into a DBX 3-way active crossover and then to separate amps for tweeter and woofer. I switch on the second signal path only when I need an extended frequency bandwidth. I also get to use the respective gains of the three signals to control the tone and warmth of the music when the recording demands that. The positive result of this configuration is obviously the unadulterated flowing vocal and mid-range based music. The negative is that the crossover is not really clean, in the sense that I am depending on the natural roll off of the full-range speaker on both ends. So there may be some overlap and phase issues in those frequencies. There is no perfect solution in this world, so each one of us has to find our own compromises

I did try connecting the full-range amp through the active crossover. That does give me more control, but takes away a bit of the the transparency and fluidity from the mid-range.

Regards,
Sharad Medhavi

 

[Beast_of_burden]

Very nice amplifiers. You have had better luck than me in having Viren build bespoke versions.

I myself run a Lyrita 2A3 but it has James OPTs and Sovtek 2A3 tubes. The James OPTs are set for 3.5K impedance loading against the 5K in the stock amplifier. The OPTs cost a full 45% of the cost of the amplifier I bought from Viren, still it wasn’t a huge amount and brought significant gains. Sadly James has ceased production. Sowter and Hashimoto are excellent alternatives. While on a trip to Singapore I happened to walk past Well Audio and on a whim bought the Sovtek tubes, the amplifier was completely transformed after the Sovtek tubes. I had used the Sovtek tubes in a different amplifier so had a hunch that it might work, wirh tube rolling you never know.

The only issue I have is the loud hum. I run Klipsch rf3(20 years old probably) which are very sensitive. I also run a subwoofer and use the internal crossover of the sub with good results. However the modded 2a3 amp by itself sounds very extended at either end of the frequency spectrum. It’s got a nice sense of touch as Art Dudley likes to put it. I run the sub to take some load off the 2A3. Except for the hum the Lyrita 2A3 with the mods is something I could live with for a long time. With the mods, it’s a totally different amp from the stock though in the way it sounds.

 

[smedhavi]

I tried Sovtek 12AX7LPS on one of my phono-preamps but preferred JJ. I believed Viren when he recommend against trying other tube options on his 2A3 power amp. We had a discussion about my speakers (big boxes running Audio Nirvana 15" fullrange high sensitivity drivers), and he recommended 2A3 against 300B. As I don't need the extra wattage. I typically have the preamp volume at 10PM position. He also said that after trying a lot of tube options he feels that there was not much of a point for me going for other tube options. I have a lots of 12AX7 and 12AU7 tubes but never tried any other 2A3s
It would be great if someone could share the sound characteristic differences between Viren's stock 2A3 & 4P1L vs other options. But remember that he is using 2A3C not the classic 2A3. Viren's words when he finally shipped my amps "Most of the tubes are Russian, and specific to these designs - so, no substitutes. The amps have been tweaked to the maximum; nothing left to upgrade". So I would be very careful.

- Sharad

 

[anilva]

I tried Sovtek 12AX7LPS on one of my phono-preamps but preferred JJ. I believed Viren when he recommend against trying other tube options on his 2A3 power amp. We had a discussion about my speakers (big boxes running Audio Nirvana 15" fullrange high sensitivity drivers), and he recommended 2A3 against 300B. As I don't need the extra wattage. I typically have the preamp volume at 10PM position. He also said that after trying a lot of tube options he feels that there was not much of a point for me going for other tube options. I have a lots of 12AX7 and 12AU7 tubes but never tried any other 2A3s
It would be great if someone could share the sound characteristic differences between Viren's stock 2A3 & 4P1L vs other options. But remember that he is using 2A3C not the classic 2A3. Viren's words when he finally shipped my amps "Most of the tubes are Russian, and specific to these designs - so, no substitutes. The amps have been tweaked to the maximum; nothing left to upgrade". So I would be very careful.

- Sharad

I am not an expert on tubes, but I know that 2A3C is not a classic 2A3 and is supposedly lot more closer to the 300B type sound. Some of my friends have immensely benefited by replacing the 2A3C tube with classic RCA 2A3 tube in their Lyrita amps. Even Viren Ji is offering RCA 2A3s in his current production.

 

[Rajiv]

I tried Sovtek 12AX7LPS on one of my phono-preamps but preferred JJ. I believed Viren when he recommend against trying other tube options on his 2A3 power amp. We had a discussion about my speakers (big boxes running Audio Nirvana 15" fullrange high sensitivity drivers), and he recommended 2A3 against 300B. As I don't need the extra wattage. I typically have the preamp volume at 10PM position. He also said that after trying a lot of tube options he feels that there was not much of a point for me going for other tube options. I have a lots of 12AX7 and 12AU7 tubes but never tried any other 2A3s
It would be great if someone could share the sound characteristic differences between Viren's stock 2A3 & 4P1L vs other options. But remember that he is using 2A3C not the classic 2A3. Viren's words when he finally shipped my amps "Most of the tubes are Russian, and specific to these designs - so, no substitutes. The amps have been tweaked to the maximum; nothing left to upgrade". So I would be very careful.

- Sharad

Hi,

The 2A3C is among the better new production 2A3 tubes available. Anil is right, it is constructed like a 300B but with 2.5 volt filaments. Sharad your Lyrita 2A3 amp can use the 45 tube in the output stage without any modification. NOS 2A3 tubes and the NOS 45 tubes are a big step up from new production tubes. If you are using your 2A3 amp only to drive the full range driver above 100hz I suggest you try the 45 as the output tube.
The Russian tubes Viren uses are very good. Soviet era tubes are very good and are gaining a following among the tube DIY crowd. If you want to try tube rolling in his 2A3 amp the only tubes you can change is the rectifier and the output tube. You can try the GZ34,GZ32, 5V4G, GZ30,5U4G rectifiers in the 2A3 amp. That said the stock Russian rectifier is also very good. In the 4P1L pre amp you can try the 6x5 rectifier,but check with Viren because the earlier versions of the pre came with a different rectifier .

The different rectifiers give you slightly different presentations and you can tune the amps sound to your taste.

Regards
Rajiv

 

[smedhavi]

I am not an expert on tubes, but I know that 2A3C is not a classic 2A3 and is supposedly lot more closer to the 300B type sound. Some of my friends have immensely benefited by replacing the 2A3C tube with classic RCA 2A3 tube in their Lyrita amps. Even Viren Ji is offering RCA 2A3s in his current production.

So you mean that the 2A3C tube can be replaced with classic RCA 2A3 without any other modification needed in the amp?

 

[anilva]

So you mean that the 2A3C tube can be replaced with classic RCA 2A3 without any other modification needed in the amp?

Yes. That’s what my friends did in Lyrita 2A3 amp. No modifications. Rajiv will be able to comment better. Or you can check with Viren as well.

 

[prem]

Yes. I had replaced the 2a3c with NOS RCA 2a3 grey plate tubes. No issues

 

[Beast_of_burden]

My subjective opinion is that a simple change of tubes will not yield a dramatic difference. The OPTs need to be upgraded as well. I tried the various impedance loads before settling on 3.5K, the James OPTs provide several options. It sounded the most balanced and extended at this loading. Note however that the recommended minimum value is 2.5K for the 2A3. It is possible that the Lyrita is more optimal with the 45 as the stock OPTs are 5K which is the recommended minimum value for the 45.

I am sticking to 2A3 because I am sure that there is going to be a reliable supply of new production tubes for very reasonable money.

From a power standpoint, the 2A3 can drive a Klipsch RB series bookshelf quite easily. It also drives my RF series Klipsch floorstander with 2 woofers reasonably well. I would hesitate to use either the 45 or 2A3 in anything other than front loaded horns or in a biamplified setup. Currently, the 2a3 lets me get away without biamping and all the added complexity. I do not like massive speaker setups that take up half the room. Been down the DIY route and done that.

A lot of reputed manufacturers use the Sovtek. I haven’t tried NOS 2A3 yet, maybe at some point in the near future. My 2A3C Shuguang pair available if anyone is interested.

I would love to see Viren offer a PSE or PP version of the 2A3. A much simpler input stage using either the 6SN7 or 6SL7 as drivers would also be great.

 

[prem]

Agreed beast of burden. The output and interstage transformers are IMO extremely important. Lesser transformers saturate faster and have limited bandwidth.

In a SET amp I would put all my money on the output and interstage transformers, followed by power supply