The point of an 845, 211, 805 amp?

[Wavebourn]

Speaking of SS Amps, Shure Vocal Master amps had feedback by current. They had high output impedance. Could run with shorted outputs, unlike other SS amps of the era.

 

[Bigun]

... unlike other SS amps...

except for your clever use of a transistor-diode LTP topology on some past projects which exhibits CCS behaviour under short conditions

 

[Wavebourn]

except for your clever use of a transistor-diode LTP topology on some past projects which exhibits CCS behaviour under short conditions

Yes, it was even better. Feedback by voltage when behaves, or by current when overloaded. Kinda toobey.

 

[tomchr]

Things the 845 can do no other amps can:
1. makes you cry listening to opera songs
2. reproduce lower octaves of a grand piano
3. literally being able to track the singers exact footsteps as they move and sing on the stage.
4. look at teenagers reaction when you play dr.dre, and feel deep vibrations
5. so, the 845 is like being high on some drugs listening to your music, its the perfect music enhancer, inside that bottle occurs some illegal music expansion from another universe.

That marketing copy would apply to my Modulus-686 as well. Except point 5. The Modulus-686 doesn't enhance the music. It just reproduces it faithfully. Then again, the only psychoactive drugs I use are caffeine and alcohol, so what do I know...

I designed my DG300B because I could, and because it's a cool looking legendary tube. No transistor will ever replace the glow of a mesh plate 300B. Sometimes "because it's cool" is the reason.

Tom

 

[Bigun]

After reading that I just want to rush out and send you some money there Tom for one of your great amps

 

[Lingwendil]

Do it

Closest thing to a perfect wire with gain that you're likely to find if you're into that sort of thing. I would if I had that sort of disposable income.

 

[Bigun]

I'm going to build something with a big bulb, an SV811 or 845.

 

[dhaen]

Go for it!

I'm going to build something with a big bulb, an SV811 or 845.

They're both great valves. Which, depends on how much power you need..
I've been running 845s in A2 for 10 years with no problem. Don't know how SV811s behave in A2.

 

[JohnnoG]

The Image shows my commission built P/P 845's.

 

[dhaen]

The Image shows my commission built P/P 845's.

Very nice. How well do they drive the ESL57s?

 

[Bigun]

They're both great valves. Which, depends on how much power you need..
I've been running 845s in A2 for 10 years with no problem. Don't know how SV811s behave in A2.

I'm actually thinking of planning for A1, wasteful perhaps but I'm intrigued by the whole Sakuma-san philosophy which is all A1.

I have some SV811's already. But they are no longer in production whereas the 845 is so I may build with the SV811s but keep the design & build open for experimenting with an 845. Most of my projects have been a bit wimpy, worrying about wasting heat etc. With the big toobs, may as well just jump in and burn some watts

 

[JohnnoG]

The general view of the visitors to the room on this day, was that I was delivering Bass that is very unusual for a 57, these have enough clean fast bass to play Eminem full throttle.
The design of the Amps was all about the 57's, Out Trans also have 8 and 16 Ohm Taps.

 

[dhaen]

A1 is perfect if you don't need the power, and is much easier to implement.
When I started my SE project (in the distant past, checking back it's 13years!) I was intent on using some other Svetlana valve that's now discontinued and I can't remember the number. Anyway I settled on the 845 because of supply continuity.

 

[dhaen]

The general view of the visitors to the room on this day, was that I was delivering Bass that is very unusual for a 57, these have enough clean fast bass to play Eminem full throttle.
The design of the Amps was all about the 57's, Out Trans also have 8 and 16 Ohm Taps.

That's good to hear. I have electrostatics and find that because the impedance of them falls with frequency, I need to boost the HF a little to get a flat frequency response.
My rig is SE with no feedback so the output z is a bit on the high side compared with feedback amps.

 

[Bigun]

Anyway I settled on the 845 because of supply continuity.

There is a large range in prices for these valves and I wonder if the low price Chinese tubes are a false economy or a good way to get started ?

 

[grovergardner]

There is a large range in prices for these valves and I wonder if the low price Chinese tubes are a false economy or a good way to get started ?

In my experience they were fine for starters. You will get a very good sense of the sound and they will play music well. ;-) I have found the budget Psvane HiFi series of tubes to be good value for the money. If the project turns out to your liking you can move up. To be honest, I never cared for the fancy metal-plate versions.

 

[45]

There is a large range in prices for these valves and I wonder if the low price Chinese tubes are a false economy or a good way to get started ?

As you are in UK I suggest the Billington Gold 845. It's Chinese but carefully selected and tested. No need to buy anything else really. It's a GE copy.

 

[45]

I'm actually thinking of planning for A1, wasteful perhaps but I'm intrigued by the whole Sakuma-san philosophy which is all A1.

I have some SV811's already. But they are no longer in production whereas the 845 is so I may build with the SV811s but keep the design & build open for experimenting with an 845. Most of my projects have been a bit wimpy, worrying about wasting heat etc. With the big toobs, may as well just jump in and burn some watts

I remember the SV811-3 and 10 when they came out. They were appealing but then I found out that they are less efficient than other NOS types. To get a measure they have a max plate dissipation higher than a 300B but output power is about 1/2......Anyway the SV811-3 is better suited for A1 operation.

 

[Bigun]

As you are in UK I suggest the Billington Gold 845. It's Chinese but carefully selected and tested. No need to buy anything else really. It's a GE copy.

I will be visiting Hong Kong and I wonder if I can purchase them there at a lower price ?

 

[fred76]

I'm actually thinking of planning for A1, wasteful perhaps but I'm intrigued by the whole Sakuma-san philosophy which is all A1.

I have some SV811's already. But they are no longer in production whereas the 845 is so I may build with the SV811s but keep the design & build open for experimenting with an 845. Most of my projects have been a bit wimpy, worrying about wasting heat etc. With the big toobs, may as well just jump in and burn some watts

This low B+ version from Jim Doyle looks nice.. Sorry, I don’ have the PSU schema. IIRC, it uses mercury vapor rectifiers in an outboard chassis.

845 Amp - Iteration 3 | Flickr