Intact Audio

@Dave: Sorry for my last (confused) Emails. I should have shut up and measured first. To everyone of the smart people discussing LCR filters here: I built a phono pre: Triode -> 4:1 interstage -> 600R LCR -> 1:4 step up -> triode -> 1:1 output. Dave wound the 4:1 interstage and in circuit (measured...

Just to loook.
In attach the last stuff I made
LCR "full trafo" 14 irons, all custom made for me.
6 are inside active box.

@Dave: Sorry for my last (confused) Emails. I should have shut up and measured first. To everyone of the smart people discussing LCR filters here: I built a phono pre: Triode -> 4:1 interstage -> 600R LCR -> 1:4 step up -> triode -> 1:1 output. Dave wound the 4:1 interstage and in circuit (measured...

Hi This is the last version of the LCR phono stage completely mounted. Full dual mono. Two toro trafo, two HT regulated supply, double circuit on each pcb that supply one section of the eachn LCR board Holco and Resista with pp caps (selected) for ative stage Two filaments regulated board I have rea...

to western I mean that you may trim the perfect curve puttin in parallel to the 600 ohm on the output of Lcr network a proper resistors. In my case with the source driving of around 200 ohm ( CF of the PCC88) I put 1k8 on parallel of 600 ohm. The response without this trimming is little bit worst at...

Hi In attach the proto of Full Tango with 999 in input, interstage NP206, EQ2L, NP206. I have also tested 11303 and 11107, rares. With EC8020; then check with EC8010 and E280F In addition the freq. answer of the phono with some adjustement on components. The results is very fine but to get this you ...

Very fine!!!


Walter

Hi I have tested some cap for bypass, last productions, declared 105° and 125 °. They are very fine, in addition with a proper bypass, in my opinion, the final results will be at high level. I use value around 330-1000 uF ( depends on Rk) , 25 Vdc; Nichicon, Kemet. I have some Cerafine 220 uF, very ...

Hi regarding bias personally I don't like to mix sand with vacuum :) So I used a cathode resistor and cap with around 20-25 mA of bias and around 200-220 Vdc perfectly stabilized with ss ( sand!), this because I got a very good s/n that is one of most important goal, in my opinion. Also the Thd was ...

to WE First of all do you have a proper test set? Only following the results of a test lab you can reach the right results. If you check the pdf from Docali : Practical Considerations on Designing and Measering LCR RIAA Filters Dr. Bernd Ahlswede (May 2018) it gives you the right direction, with a g...

Hi WE300 In attach another test with only the LCR stage The previous one ws with Zsource 600 ohm and Zload = 600 ohm, 10k. 47k and 100k This one is with Zs = 20 ohm, 100, 200 and 60 ohm and Zload = 600 ohm, as Tango specs lcr risp Zs_20_100_200_600_zload_600.jpg Tango These are real test and not sim...

Maybe you haven't read my previous post where I specified my error. Then the input of circuit connected to out of the LCR network see the 600 ohm in parallel, in case of TH. design, with 1M5. If I put , p.e. 10k, the circuit see 600//10k. In my case I decided to use 600 ohm as load of LCR and a vari...

The text is correct. The Tango data sheet for EQ600P show the network closed to 600 ohm. Other configurations ( as I use, in case) aren't compliant with the Tango indication. If you don't close the network with 600 ohm the Z is higher respect the original diagram. This can be seen from my diagram; m...

Hi please don't write things not real. I never said the I don't want to make a test. And the diagram with curves is itsef a test (real) where you can find the Z so your simulation is not necessary. I wrote also a little explanation To be precise, I wrote the reference at 1 kHz as reference point; it...

Hi the condition of my the test is described. The Zin referred ay 1 kHz is 600 ohm The 6 dB of loss when I move from an high load (33 or 47K, 10K the loss is a little bit lower) to 600 ohm give us the Z Note: one error on my post, the Zload is the parallel of 1M5 and the Z of network. Note2 = the Th...

One add. In the Th. schematic there aren't the 600 ohm in input and 600 ohm in output of the LCR. The EQ600P the 600 ohm are outside the LCR circut (that is inside the box). In this case the Zout of the gain stage is 600 ohm, it is a Zin of network, but the load is the 1,5 Mohm (in ac). And, as the ...

You have 300 ohm only if you have Zs 600 ohm and Zload(network) 600 ohm.
Then if you look at the graph I sent you can see the response
Zs=600 ohm
Zload= 100k, 47k, 10k

The blu at 0 dB line is Zs=600 ohm and Zload =600 ohm

This is a LCR network only


Walter

In the last schematic the EQ600 is not terminated with 600 ohm so load seen by input stage is higher
The another ptoblem is the overload of ths circuit; with 5 mV at 1 kHz the 30dB are too low for me

Walter

Regaridng the bias the last solution, cathode to ground, is very good, it depends of the tube.

W

The schematic on Thorsten is not correct.
In attach the one correct

The point of view of Th is that the flat response on RIAA is not so important; this is an opinion, of course.
The solution he did is about the less precise configuration from Tango EQ600 data sheet.

Walter

This is the las version of my LCR
I am playing now with the version full trafos, (possibly) two stage.

Walter

After finished a LCR with pcb I will prepare soon another LCR but full trafo.
If you want youn can see something interesting in nexth one moth

Walter

Hi I have seen this thread. I ma writing some article on Audioreview magazine in Italy about LCR phono. In the second part I have presented some real test on LCR stage only ( in the next two parts will be presented two different complete circuit). So some things maybe helps. In first attacch, Figura...

As I wrote the Triple is not on the market and is not possible to buy. Then the test lab is fine, this is a real test not simulation. In addition soon I will send a beautiful diagram done by a particular software (not commercial) that plot the real parameters of coils, resistor and caps. In every ca...

Hi in attach the test of Triple at 1:10 ratio with 100k, 47k and 27k load. There are three lines that are perfectly equal. It is difficult to see!! I will try to arrange a setting for higher load for trafo The reponse is fine, in absolute. Compared with Altec in much better At 20 hz the shift is +2,...

Hi the facts are simply. Do you have the lab test that can confirm your point of view? If yes, very fine for me to learn something new. And I will do the best to get a better results. And I am ready to buy the stuff you show me better than Tango and Sowter ( at the same ratio) In addition all the st...

Each of us has the proper considerations. My idea is that the test lab on stuff are the only way to understand the way to follow. The multitap trafos are the best way to reach the results for who has different MC, in general. But, when you get the results as Tango or Sowter you can be safe about son...

This is the reason I look mainly on square wave test. On 10 kHz test the wave is quite perfect without any ringin. Each time you see a square with some ring at the end the sound seems to be althered. Also it is very difficult to get the linearity as shown on diagram of three ratios The response of t...

About phase is not so important to know, for me . But I check on my tests. Knowing the stuff from Sowter I am not worried. In my opinion much better the square wave response. Regarding the sound we have to consider that changin th load seen by cartridge we also change the damping The sound you can e...

I am reading this old thread. On nr. 400 of Audioreview we have spoke about the stp up ) in that case the 999 Tango) with different load on secondary. Very interesting resiults, lot of test lab. Then I buil the one in photo with a custo trafo, 12.20 and 40 ratiod, made for me by Sowter There is a El...