Anzai SRPP line, phono and EQ tube preamplifier

[Soundhappy]

Long time a go i meet in my town electronician and meloman who build DIY version of SRPP Anzai.
I was happy winner of the second hand auction.
Thanks You very much Mr. Gilles
Was the time of serious explorations with class A Hiraga 20 Watts and my first tube preamp at home.
Now after many years i am into electronic hobby as well.
Today i decided update step by step old components inside :
electrochemical´s capacitors first and try change carbon films for new type of resistors.
Any councils are welcome and I appreciate Your experience with tube preamp's restorations and upgrades 🙂

 

[Soundhappy]

Anzai SRPP

 

[Soundhappy]

Link to Katsutaro Anzai Sensei traduction write by Mr.Jean Hiraga in "L'Audiophile " french DIY revue
Part 2 :
Le préamplificateur SRPP à égaliseur passif
Part 1 introduction by Jean Hiraga San :
Préampli SRPP

🙂

 

[Soundhappy]

Anzai Shunt Regulated Push-Pull circuit do work two triodes in opposite phase for low distortion, have high input and low output impedance. Frequency bandwidth goes up to 100 KHz. After inside verifications of the components it's first RIAA version.

Amazed by 40 ~ 35 years old preamp high grade quality construction. Connectors, Allen Bradley pot's, Elma switch and separate box for power transformer. 2/3 of all components on the large PCB are part of the power supply. The signal path is minimalists and possible to build this with point-to-point technique. Let's play now favorite records and test new capacitors and resistors candidates

 

[Soundhappy]

SRPP optimisation article in English
http://www.valvewizard.co.uk/SRPP_Blencowe.pdf

 

[67339]

Hello, I had this pre amp a few decades ago. A nice upgrade is to change the final tube into a E80cc. It has lower gain but also lower output impedance. BUT i takes double the heater current of the normal tubes! In the eighties i talked to some customers at La maison de l'audiophile. Their ideas: Raise the high voltage supply. Use tube rectifier.Depending on the desired output voltage 6X4 ( low) or higher ( to many to choose from) Use choke input power supply. At that time i had the PRE PRE Hiraga with lots of gain so no need to use the line stage. Use seperate switch for heater and high voltage power supply. With E80CC maybe need higher power resistor.

Greetings,
Eduard

 

[Soundhappy]

Choke and rectifier tube I do keep them for the next preamp build.
Change for new caps are done and other resistors under the test today 🙂

 

[Soundhappy]

SRPP update with new resistors

No more carbon film resistors in my Anzai preamplifier only mixture of low noise
metal films, Vishay bulk foils and wire wounds with tantals. Have DIY fun 🙂

 

[67339]

Hello,
That is a big cap but it looks old. Electrolytic caps will degrade when they are old. Why not use the recifier and choke for this pre amp? For choke input you will need another power transformer. Because the current is so low there are a lot of high henry low mA chokes you can use like some Lundahls. They work very well.

greetings,
Eduard

 

[Soundhappy]

Preamplifier is not finished. I do more cap's changes in the next upgrade steps. Choke psu filtering maybe, but not sure. You write me about tube rectifier solutions ?

Thanks for Your councils inputs 🙂

 

[lcsaszar]

This was my first tube preamplifier, built some 35 years ago. I evolved the circuit since then, first was to eliminate the bass/treble control. Then I separated the HF 75 us EQ from the LF 3180/318 us part, so I applied 2-stage equalization. All tubes are E88CC/6N23P, capacitors are silver-mica, resistors are Vishay naked, coupling PIO capacitors. I did not change anything in the past 20 years or so, and I am still happy with it.

 

[67339]

Hello, Choke input plus tube rectifier will give a very big improvement. Best to have a high voltage transformer with several output voltages like 450-400-350-0-350-400-450 volt sop you can change when the voltage at the circuit is to high or to low.

Probably you will need 400-0-400 to get around 330 volt at the circuit when using choke input and a tube rectifier. I can look if i have a high voltage transformer that comes close. Lundahl always worked well for me. They have several models that will work. Usually i will check how much current the circuit will take and then choose choke that can take a little extra. At lundahl you can find a 50 Henry choke that can handle 90mA. With 70 mA you can probably find one having even more Henry.

Greetings,
Eduard

 

[Soundhappy]

Old Anzai SRPP schematic from 1969 have PSU 30H 35 mA choke included
Greetings 🙂

 

[67339]

Hello,
If you want to make it a lot better you should use a tube rectifier and a choke input power supply. You need to know how much current the total circuit will draw. Then you can find out which Lundahl choke has the highest number of Henry. I think an extra choke will be better than adding a lot of capacitors.
Greetings, Eduard

 

[popilin]

Take a look here

SRPP-Vorverstärker

C7 and R5 are wrong, try C7=15nF, do not remember R5, maybe some 750K.

 

[popilin]

Sorry, found the correct values for the RIAA EQ

C4=220nF (as before)

R6=51K

R4=6K81 (as before)

C6=47nF (as before)

C7=15n6

R5=470K

 

[67339]

Hello,
There are several ones. Google for the article published in French Audiophile magazine in 1986
Greetings, Eduard

 

[popilin]

Those values come from a simulation and had been used in a real world preamp with amazing results.

 

[victordascalescu54]

I am fun of srpp since 86 when I build my first one. It still works with nice dinamic sound and I am happy leaving with.
From the begining, the PSU was my concern and I use EZ80 rectifier, shock filter and ECF82 stabilizer with best results. The config was ECC83 fist stage, ECC81/83 secound stage and ECC82 out buffer. I tried also ECC88 as buffer but I like more the sound of 82. No tone controle at all and the volume controle before the buffer.
As I am architect in my "normal" life, I liked more point to point construction "spatial building" nice, clean, no noise no compromise.
I am now ready too in making some improovments but shall be probably the capacitors as at the time there was difficult to find. About the resistors I'll change if necesarry the old MLT with modern carbon as Kiwame or Takmans which I expect to be more natural.
I'll be back with my ideeas as that thred is verry interesting

 

[67339]

Hello,
If your heater supply can deliver the current you should try E80cc for the output tube.

The 3 different riaa circuits described by jean hiraga have been used in real circuits too. I have the actual magazine published long before the nefast use of internet.

Greetings, eduard