"Shortest Way" SW51 Amp Impressions (Simple SET Amp)

I know this is supposed to be a budget headamp, but this gift from @Zampotech is really a very important amp of our times.

 

I had been on the fence about ordering another amp in this price range or just saving up for a big boy amp and now will have to wait and see what happens.

But with this talk about possibly switching some things around, one of which is the output transformers, I wonder how many people would be interested in having the Low Z out be optimized for Focals? I for one would be extremely excited about that possibility!

I have been curious if Zampotech has considered designing and producing any higher end amps in the future? If he thinks a considerably better amp could be made and sold in the $1000-$2000 range. I know the main appeal of the SW51+ is how amazing it sounds for it's price, but certainly I cannot be the first person to wonder what Zampotech could come up with given a larger budget.

At any rate, I don't mean to derail the thread. I will be keeping an eye on how this develops as I still want to own an SW51+ or perhaps some tweaked version of it down the road.

 

I had recently inquired about this exact thing to Zampotech a few weeks ago. I have a feeling a few of us have thought about a SW 102+. Keep all the great things about the SW 51+ but with more resolve, a wider, and deeper sound stage.

 

IIRC the low Zout is 27Ω. Clear impedance is nominally 55-60Ω. I personally don't find any noticeable effects on bass compared to the MCTH (less than 1Ω Zout). So I'm not sure how much difference/improvement there would be with a lower Zout.

But a souped up SW would definitely be interesting, especially if it could be ordered as a user installable upgrade.

From the "measurements only thread":

I looked around and many "Made in Holland" Amperex are branded "Zenith". Are these the same tubes? Does anyone have any specific recommendations? I quite like the Mullards I got, but the first pair started making noise and I'm on the the backup pair I bought.

 

The more I read about this future update, the more we need to know what's a budget price? To be honest, the three versions of the SW 51 from base to + wasn't really a huge price difference. I think all of us outside of Russia ordered the SW51+ since even with the upgrade it was "cheap" for us capitalist.

 

I'll give you my opinion. My opinion is based on my capabilities in technologies, methods of processing materials and possible components in production conditions in Russia.

This applies only to the headphone amplifier.

It is possible to make an amplifier up to $1000. The price will be justified by the materials and components used, the cost of research and production work.
The increase in the cost of an amplifier is not directly proportional to the increase in sound quality. The relationship is most likely quadratic. Expensive amplifiers are most likely amplifiers for audio gourmets.

In order for me to make amplifiers up to $2000 I will need to install transformers Lundahl. Tango. And several other firms.
Or get a license to work with precious stones and decorate the amplifier with diamonds and rubies.
In any other case, this will be an excessively inflated cost. The last thing I want is for a customer of my expensive amp to feel cheated and hurt to the core.

My pricing calculation only applies to Russian conditions. Low-cost production is still possible in Russia.

 

@Zampotech any ETA on the next batch of American orders being shipped out? Or Russian Post is still on lockdown ATM?

 

The post offices opened today. But the entrance is only in a mask.
This is for sending airmail. I have already called a courier to send EMS.

 

Great, we capitalism are waiting. HA!

I need more coffee.....

 

Looking forward to one here. I hope my order still stands.

 

Picked up a small lot of bargain tubes 6EJ7/EF184 in anticipation of getting the SW51 whenever it will be ready. Several of the tubes look to be of identical construction with the mesh style plate, but they are made in different countries in Europe.
All are rebranded - RCA, Zenith, Admiral.
Should I assume that the ones made in Gt Britain are Mullard?
Those made in Holland are Philips?
Those made in Germany RFT?
Even though they all look very similar, do they sound different?

 

Germany might be Siemens.

Look for the etched characters on the side of the tubes near the bottom, and on this page:

http://www.audiotubes.com/mullcode.htm

scroll down to the 2 charts under "The factory and country codes".

At the same site there are notes on the sound of 6DJ8 variants from the different factories:

http://www.audiotubes.com/6dj8.htm

(scroll down to "OK so tell me how they sound!!), but I don't know whether they're also true for 6EJ7s.

 

Hi Bio,
Thanks for your help - the trick was to look for the symbols in (almost) invisible ink!
Using a magnifying glass and turning the tube at different angles I was able to cast more light on the origins of these tubes.
All of them are from the 60's.
The made in Gt Britain tubes are all Mullard, Blackburn from the 60's
Made in Germany - found one Siemens/Halske tube and possibly the other two labeled RCA are also Siemens; maybe one is RFT.
Two tubes made in Holland are made in the Philips, Sittard factory.
Re the sound I have to wait for the amp amp to arrive. There is definitively such a thing as "house sound" but from experience each tube may sound different in different amps.

 

Give the stock tubes a fair go before you swap them out.
@Zampotech was not being cheap when he chose them.

 

^ this. The amp sounds great with the stock tubes, but I prefer it with RCA Mullards.

I bought 2 pairs of the Mullards and am on to the second as the first started making fizzy noises. Now I have 2 pairs of Amperex EF184 (Holland) coming in to compare.

Are these branded Zenith? Most of the "Amperex EF184 made in Holland" tubes I found on eBay were Zeniths. I ended up buying these ones actually labelled "Amperex", though they were a bit more expensive.
https://www.ebay.com/itm/324077138684

 

I got a pair or 64/66 amperex labeled tubes from Brent Jesse for $20. I was confused about the whole Mullard thang. I'm still confused lol. It's hard to track down the lineage in them. Some are mullards but have Holland date codes on them. Then there's all the other brandings.

Anyway I listened to the amp with stock tubes for about 2 months. I just wanted a back up pair at least. the amperex are definitely warmer. Almost like switching from leather to velour pads on LCD2c for example. I don't pick up much difference honestly, highs seem very similar. Most difference is warmer mids and slightly fatter low end/low mids I guess. need more time with them.

 

These tubes are going to evaporate completely from the market. Le sigh

 

Of the two tubes from the Sittard factory, one is labeled RCA and the other Zenith.

 

Re the Mullards, the way to determine where they were made is to look at the almost invisible four symbol code on the side of the tube, near the pins. Any code that starts with the letter B (as in B 2 G 1) are made in the Blackburn Mullard factory. The second number 2 means 1962, and the G is the month. Counting the alphabet on my fingers I come to 7 for G, which means July. Of the three Mullards I have, two are labeled Zenith and one Admiral.

 

Have no fear, as of today there are 215 listings on eBay with many more tubes:
https://www.ebay.com/sch/i.html?_fr...C0.A0.H0.XEF184.TRS2&_nkw=EF184+tube&_sacat=0