Lyrita Audio's New 845 SET

[dhiman]

Lyrita Audio has just brought out another amplifier in its range of single ended tube amps - the 845 SET. This is an integrated stereo amplifier, using a single 845 output tube per channel, with a power output of 15 watts/channel.

Why build another 15 watt amp? Well, the 845 tube enjoys an enormous reputation - I was curious to hear it for myself. Then there were customer pressures, specifically from "heliumflight"! He stubbornly hangs on to his vintage B&W speakers, of average sensitivity. The Lyrita 2A3 SET that he has was being driven to distraction, er distortion, trying to play music through these speakers! And "heliumflight" would have none other than the directly heated triode sound. There was no choice left but to build the 845 SET amp!

Frankly, I am not in the power game. You can get more power out of the 845, if you operate it to its limits. I prefer to run the tube very conservatively, to prolong its life, and to get a better measure of its sound. For me, 15 watts of SET power, with the right speakers, is more than enough in a domestic setup.

So, what does the Lyrita 845 SET add up to. It's a three stage design - the input voltage gain stage is handled by the 5687 tube, RC coupled to the driver stage using the 6V6 tube in triode mode, transformer coupled to the output 845 tube. The 6V6 provides the high current necessary to drive the 845, the interstage transformer provides the right impedance coupling to allow the 845 to run even into A2 mode on peaks. In my view, the interstage transformer is the best way to couple to the 845, and also allows the use of a fixed bias to the tube.

The power supply is beefy, choke filtered. Only tube rectification is used. And, the 845 runs on AC heater voltage. And, no global feedback is used.

Specifications:
Power output 15 watts into 8 ohms
Response 40 HZ to 20 kHz

Tubes
Input 5687 NOS
Driver 6V6 RCA
Output 845 Shuguang
Rectifier 5V4G x 2 parallel
Rectifier 5W4


Regards,
Viren

Great, Congatulations!!

 

[doors666]

40hz seems a lot higher for lower end.. is this due to the 845s or is it an issue with all tube amps. sorry, i dont know much about tube amps.

 

[gobble]

40hz seems a lot higher for lower end.. is this due to the 845s or is it an issue with all tube amps. sorry, i dont know much about tube amps.

Actually 40hz is more than sufficient for musicality to emerge through

Dont worry about it

Cheers

 

[doors666]

Actually 40hz is more than sufficient for musicality to emerge through

Dont worry about it

Cheers

I am not worried! I aint buying these right now, no money, no speakers either that are worthy of these:lol:

Just curious though. There are quite a few recordings that go below 40hz. My experience is mostly with SS receivers so just want to learn more about tube amps. Someday I do plan to go for a tube amp, I liked the tube sound whenever I got a chance to hear it.

 

[AMITNOIDA]

I got the opportunity to hear this new 15 wpc SET amp pairing with Viren's Amity speaker. The amp has a mesmarising glow and lush sound. It is bigger than Viren's other SET and push-pull amps. It should be a benchmark amp of Lyrita.

 

[gobble]

I am not worried! I aint buying these right now, no money, no speakers either that are worthy of these:lol:

Ah! You definitely want to hear the rumble and thunder of a mountain of cash hitting your house like a landslide and sweeping you away with it then ...

No wonder you are concerned about frequency reproduction of 40hz and below ... !! hyeah:

 

[viren bakhshi]

Hi,

Sorry again for responding a bit late. Let's see if I can answer all the technical questions.

As far as frequency response goes, the 845 tube will amplify signals from very low bass to radio frequencies. However, the tube has to sit in an actual amplifier with input stages, and an output transformer. These elements all interact to limit the overall response of the amplifier. The specified frequency response should be that at full power output. The core size of the output transformer determines the extent of low frequency reproduction. A large core size however is detrimental to good coupling between windings, which reduces the high frequency response. So, the transformer is a balancing act. The 845 SET amp will reproduce low bass down to 20 Hz, but not at full power.

Distortion in tube amps is again a subjective thing. When you do distortion measurements, you take a signal voltage, either a sine or square wave, and drive the amp to its limits. Usually, a gross number is specified as THD. It does not take into account the harmonic spectra of the distorted wave; spectra which is critical to our perception of distortion. As such, THD becomes meaningless. In tube amps, distortion comes on gracefully, because the spectra is not harsh sounding. You will certainly hear it, if you drive the amp well into distortion, as the sound breaks up and becomes warbled. Before that, distortion will be heard only on peaks, usually on a bass transient, and will not be obvious because the loud music will mask it to a degree.

Using feedback to get a more correct THD number again is meaningless. Feedback corrects the low harmonic content, but generates additional higher harmonic content different from the original signal. This actually gives a harsher sound compared to the original. A better option is to design very linear gain stages, which don't require feedback at all.

Tube amplifiers have their limitations too. Damping factors are low (though that's one thing that benefits from feedback), and low end control of a speaker is affected. That's why you have to match the right speakers with tube amps - think of systems!

Regards,
Viren

 

[prathik]

Yo Viren,

When will you do this in mono bloc???? I have got too used to the monobloc seperation!!

And when can we do a hearing over at my place...over some excellent wine that I have just discovered!
cheers
Prathik

 

[captrajesh]

The core size of the output transformer determines the extent of low frequency reproduction. A large core size however is detrimental to good coupling between windings, which reduces the high frequency response. So, the transformer is a balancing act.

Can't we have caps in between to act as power reservoir.

This member has violated the forum rule "Only a dealer, distributor, manufacturer or service provider who is a sponsor member can directly discuss and promote their products and/or services with other members." and has been warned!

I thought this discussion was about 845 tubes.

 

[panditji]

This member has violated the forum rule "Only a dealer, distributor, manufacturer or service provider who is a sponsor member can directly discuss and promote their products and/or services with other members." and has been warned!

Moderator: Instead of the dealer being warned, kindly warn all members not to directly ask questions related to audio to the dealers who are not sponsored members. The members should be informed to use this forum only to send private messages if they have any questions related to audio or switch to Blackberry instant messaging.

All dealers who are not sponsored members, kindly share your encryption codes with the forum moderators so they can read between the lines when you are selling your products while replying to a simple query.

 

[rikhav]

Very true Panditji

This whole thing is becoming one big mess, too many rules, too many this and that

I think we all memebers will need a Hifivision rule book soon when we write any posts

 

[hifiashok]

guyz!

lets give the moderators (and site owner/s) a break. they r just doing their bit, and, if i may add, gratis (for the luv of the passion, being audio) (IMHO, of course). running a site like this, maintaining it and sustaining it through all these years costs money and commitment (not large, but enough to matter, or there'd'v been many more of us cluttering the inet with upstart, short-lived sites). consequently, rules need to apply (and differentiate) for the few of us who pay for an expectation of return and those of us that just leech (read 'constructively contribute').

as i submit the a/m i need to clearly share, i personally respect virenji as a thorough gentleman and for a lot of things and have no motives here (i kno i do not need to say this to him, as he would understand, but for the larger populace's benefit).

an nice suggestion (if agreeable, of course) would be to contribute to virenji becoming a 'sponsor' here (not that i doubt his ability to do this himself). it would only be as manna for the excellent reads that all of us enjoy coming from him (and a lot of others like him, from time to time). i kno, one school of thought would say, people flock to such sites only coz of content from mature, leaned members like him; that's how sites sustain, not on funds but on content, blah! but then, that would be a very subjective call.

trust i have trod on no toes and ruffled no feathers, inadvertently.

 

[doors666]

The 845 SET amp will reproduce low bass down to 20 Hz, but not at full power.

I am curious, is this the offending line, I dont see anywhere else in the mail the product or its features being discussed. I think this is directly in response to my question. While if you see the first mail in this thread, its nothing but giving all the information about the product. And that one is not being flagged as warning.

 

[hifiashok]

I am curious, is this the offending line, I dont see anywhere else in the mail the product or its features being discussed. I think this is directly in response to my question. While if you see the first mail in this thread, its nothing but giving all the information about the product. And that one is not being flagged as warning.

friend, the thread in toto, not just your post, IMHO, of course, if you read the moderator's comment/s. so, stop blaming yourself.

 

[panditji]

Ashokji, are saying Virenji needs to become a sponsor to explain the nuances of tube equipment to interested parties? I understand there are costs involved in running and maintaining a website but I do hope a passion for audio is the main reason why somebody is running this forum. Anybody with a passion for audio should have been happy with such threads and not be flagging such threads.....

A forum is meant to be open and if someone is peddling their stuff it is a different thing. If someone is asking a technical question about a product which will be beneficial to everyone, I see no reason why it should be flagged. I have no plans on buying tube equipment anytime in the near future but I still read the post and thought I had become wiser although I did not understand much. But only after reading such posts will I become more knowledgeable.

My apologies to the moderator for the outburst but I felt this is not right and will drive people away from this forum.

Warm regards
Rahul Pandit

 

[stevieboy]

Panditji,

I think Viren himself would agree with the decision taken, you might want to read up on the rules of the forum beforehand before making a post. The rules clearly state only sponsor members can promote their products. This was a press release so unless Viren's a sponsor member he can't do so.

Explaining tube gear's merits is another question and the fact is moderators woke up pretty late and ad hoc made a warning in a post somewhere in the middle of the thread whereas they should have flagged the first post itself if it was against the rules. The common sense moderating decision would have been to flag off the original post instead of some random post which was actually answering a tech question which would have avoided all this confusion. Or perhaps made a new post stating the case.

To their credit the mods seem to be fair enough to allow this thread to continue on technical lines since people are asking tech questions, instead of closing it. So let's take the good moderating decisions with the bad and roll on. Pun intended

regards

 

[hifiashok]

Ashokji, are saying Virenji needs to become a sponsor to explain the nuances of tube equipment to interested parties?

no, absolutely not. and neither are the mods in this case (IMHO). guess it is a fine line and could be missed if not carefully examined. as a matter of fact there are a lot of posts from virenji, generic and toob specific, that have been immensely appreciated (and of course, added to all our 'knowledge' and better understanding). pl. note, i am taking no sides here, just stating facts, as they seem. btw, virenji seems to be in quite a unique position (since other similar niche designers/producers of eqpt. are not active on this forum, again IMHO. most sponsors here are 'resellers' at times adding value) and may seem to be paying the price for that here.

I understand there are costs involved in running and maintaining a website but I do hope a passion for audio is the main reason why somebody is running this forum. Anybody with a passion for audio should have been happy with such threads and not be flagging such threads.....

guess being a mod is quite a thankless job, after all.

A forum is meant to be open and if someone is peddling their stuff it is a different thing. If someone is asking a technical question about a product which will be beneficial to everyone, I see no reason why it should be flagged. I have no plans on buying tube equipment anytime in the near future but I still read the post and thought I had become wiser although I did not understand much. But only after reading such posts will I become more knowledgeable.

My apologies to the moderator for the outburst but I felt this is not right and will drive people away from this forum.

Warm regards
Rahul Pandit

 

[soulforged]

congrats viren sir...hope to hear it during my next visit to delhi...

ps: will put money in my piggybank more frequently now

 

[keith_correa]

The rules clearly state only sponsor members can promote their products. This was a press release so unless Viren's a sponsor member he can't do so.

Explaining tube gear's merits is another question and the fact is moderators woke up pretty late and ad hoc made a warning in a post somewhere in the middle of the thread whereas they should have flagged the first post itself if it was against the rules. The common sense moderating decision would have been to flag off the original post instead of some random post which was actually answering a tech question which would have avoided all this confusion. Or perhaps made a new post stating the case.regards

Thank you! Thank you! At least you got it. Unlike the other overreactions. Count till 10 guys. These days I do.

 

[captrajesh]

will put money in my piggybank more frequently now

Over to Gobble for expert comments.


@soulforged. Just a light hearted post to lighten the situ, no offenses meant.