• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

DRD Amps

Status
Not open for further replies.
Jump to Latest
#21
Hi,

Hello , anyone allready did construct the Pultec pc-10 phono-stage developped by Western Electric engineers.
Click to expand...

I'm having something similar in the pipeline, unfortunately my pipeline is starting to look like an Iracqi oilpipe but...I'll get there one day.

I'll check with Benny Glass if he's got the LCR RIAA correction from Lundahl ready now.

Cheers,😉
 
#22
Hello Frank, Years ago when a French audio group was starting to search for parts for this phonostage i did ask Lundahl to wind the chokes for the lcr-filter they were not interested. I allready did have the Tangos but there were quiet a lot of people who did leave the boat when they realized that this part would be EXPENSIVE. Now Tango is out of business and Lundahl will give it a try. We will see. ed
 
#23
Hello, I forget let us get back to the monkey and continue the phonostage somewhere else. My monkey- circuit is designed by another audiofanatic in Holland. If it will work and he will give permission i don't mind putting the schematic out here. In the end i will use it above 600 hertz with a 109 db system so it will have an easy life. Ed
 
#24
Hi,

Ed,

Now Tango is out of business and Lundahl will give it a try. We will see. ed
Click to expand...

I already held the prototypes in my hand_like a proud daddy_, but the nice folk at Lundahl had made a mistake on the value of the first self.

They're not expensive at all when bought from Benny and I think they should be on sale right now...I can have it confirmed if anyone's interested.

BTW, Tango is NOT out of business, just reorganised and fused with another company or something like that.
Unfortunately the range of product has changed in the process.

Cheers, 😉
 
#25
Hi,

In the end i will use it above 600 hertz with a 109 db system so it will have an easy life. Ed
Click to expand...

At 109 dB/1M it'll fall asleep...😉

For those of you not knowing what a VT25 is, it a military name for a 10Y.

Relatives are the VT62/801.

The VT25 is an extremely good sounding low power DHT and much sought after by the Asian audio geeks.

Cheers,😉
 

Attachments

  • 10ysylvania.jpg
    10ysylvania.jpg
    9.8 KB · Views: 512
#26
Bas; I E-mailed Jack Eliano who is the designer of the amp and he indicated that both solid state or tube rectifiers would sound fine because of the isolation factor. Ron Wellboune who sells the DRD as a kit offers it in both configurations and states that he actually prefers solid state for this amp. Once again, I have never heard one so I could not tell. Hope to hear from you when you are "in process" of building.

Cheers'
Pete
 
#27
Hello Frank, Yes, i do know what did happen to Tango because i did order in Japan several times. A lot of things are not made anymore by the successor. It is a real pity because they allways did give good results. By using Tango and Tamura i wanted to be sure that if it will not sound okay it is the schematic and not the components.Maybe there are companies in Europe who can make a good VT-25 single ended opt. But most companies will have some good opt and the rest are just average. I will use this trannie for a few decades so a price 100 % higher will not make it too expensive. Ed
 
#29
Hello Frank and you all, I did make the decision about 10 years ago to buy the Tad-2001 to give myself the possibility from escaping the 300B prices. The amps that i did hear with vt-25 were all very musical and i suspect that the monkey circuit with its minimal approach will let it perform even better. The only possible tweak is creating the cathode tension not at the input tube but by using an extra resistor in the vt-25 circuit. This will give you the possibility to ommit the capacitor at the cathode of the input tube. This will be my first tweak. In the beginning it will be used full range but soon it will be above 600 hertz so maybe then the influence of this tweak will be less or more??? ed
 
#30
Hello Frank, He did wind the double c power transformers. But everybody tells me that a vt-25 OPT is rather difficult. So i did decide to go for a 7000 ohm permalloy Tamura. Ideal would be higher but i can use another secondary tap. Ed
 
#31
Hi,

So i did decide to go for a 7000 ohm permalloy Tamura. Ideal would be higher but i can use another secondary tap. Ed
Click to expand...

Yes, you could use a 7K Tamura and tap from another secundary, no problem.

If I have the energy, I'll check with Jean Hiraga's data on the OPT, if I see anything objectionable I'll let you know.

Cheers,😉
 
#32
Hi,

Ron Wellboune who sells the DRD as a kit offers it in both configurations and states that he actually prefers solid state for this amp. Once again, I have never heard one so I could not tell. Hope to hear from you when you are "in process" of building.
Click to expand...

In a well designed state of the art PSU this should not matter at all.

Still, nothing ever being perfect, yes I can understand why Ron prefers it... the Shottkys are much faster giving better bass response and faster sound overall. ( better transient response, technically speaking)

No surprise there,😉
 
Status
Not open for further replies.
Top Bottom