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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Which tubes should I use?

Janez

Member
2007-11-17 12:49 pm
Hello

I have a lot of new and used tubes, but I will write only those that may be usuable for audio:

Dual triodes:
1x 6CG7 (U.S.A.) like new
2x ECC82 (Philips) like new
1x ECC83 (Philips) like new
2x ECC88 (Tesla, Philips) like new

triode+pentode:
5x PCF80 (Tungsram, Ei, RR) like new
1x PCL80 (Rayton)
2x PCL82 (Philips)
3x PCL84 (Ei)
4x PCL86 (Ei)

pentodes:
3x EL84 (Ei) NEW
2x EL86 like new
1x PL36 (Japan) NEW
6x EF80 (Ei, RR) like new
2x EF85 (Ei, RR) like new
2x EF184 (Siemens, Ei) (one like new, other one doesn't look too good)

Rectifier:
5Y3G (Fivre) NEW

I have also 2 output transformers from old radios.

I would like to build:
- small stereo amp with 2x EL84 + 5Y3G + (some input tubes ECC??/EF80/PCF80...)

- stereo line preamp with tube regulated PS (ECC??/EF80/PCF80/6CG7/... + regulator tube PCL??/EL84/EL86/PL36/...)

- stereo hybrid amp like Aikido (ECC??/EF80/PCF80/6CG7/...)

Please help me chose which tubes should I use for each project, that all of my projects will sound good and there will be no need to buy new tubes (if possible).

I don't mind if only triode is used in PCF80.

Regards
 

Janez

Member
2007-11-17 12:49 pm
From your links I decided to build SE84 as I have 2 brand new EL84.

This is the hybrid amp I was writing about: http://www.tubecad.com/2006/04/blog0058.htm
I'm capable of building only one channel using ''original'' tubes(ECC83 at input + 6CG7 at output)

Would it work if I put ECC88 at input of Aikido and ECC83 at input of SE84? I was also thinking about using ECF80 at input of aikido. At output I think I could use ECC82 (or 2 triode connected EF80?). I'm lost again :D

Is EF80 of any audio use? Let's clear this first, so I can take it out of my list.

I need linestage as I have different sources : computer, tuner, TV, CDP and with some of them I don't get enough gain.

Strange voltages for heaters are not a problem for me. I have a lot of different transformers.

I did a little research and found this shematic for linestage that EC8010 has drawn. I'm going to try it.
 

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ray_moth

Ex-Moderator
2004-01-27 8:55 am
Jakarta
For a small signal pentode to be good for audio use, it must primarily be a sharp cutoff type with low noise and low microphony. It also needs to be linear, some pentodes being considerably less linear than others. The EF86 is a well-known example of a successful audio pentode, but it's not the only possbility. I have never tried the EF80 but I seem to remember other people saying it sounded OK, either as a pentode or strapped as a triode.

Probably one of the most useful roles of a small signal pentode in audio is as a CCS. For example, in that line stage shematic from EC8010 a pentode is used as a CCS load for a cathode follower. Pentodes also make good cathode followers in their own right.
 

Janez

Member
2007-11-17 12:49 pm
Ok, I decided to do it this way:

- line stage with 2x PCF80. I don't know yet which tube(s) I will use for regulator.

- Aikido hybrid with 2x ECC88 at input and 2x ECC82 at output

- RH84 with 2x EL84 and 1x ECC83

I will also try how triode connected EF80 sound compared to ECCs
 

Janez

Member
2007-11-17 12:49 pm
2x PL509 (used), 1x PCL80, 1x 6KR8, 1x 6jz8, 1x PCF802, 1x PF86, 1x PCH200, 1x EBF89, 1x EF183, 2x ECH84 1xECH83 and 2 tubes that have no markings (one looks like EL90, other one looks like EF80 but without perforated mesh for anode).

Except half wave and HV rectifiers this is all I have.
 

Janez

Member
2007-11-17 12:49 pm
http://img225.imageshack.us/img225/9945/img1841hu2.jpg

At left you can see type of housing I'm going to use for RH84 and line stage. It is from old ISDN modem, I have 5 of them. PS will be separated, as I don't like to mix 230V AC with line levels. At left you can see also my homemade USB sound card. I didn't get enough gain to test amplifier at full power, I terribly need line stage.

I built this amplifier a couple of years ago for testing purposes. It has adjustable bias and HV delay. I just changed one chanel to RH84, other one I left in triode connection as reference. I can say that RH84 has a little more bass and it also sounds better at higher freq. Aligator clips go to resistors that you don't see at the picture. Speakers are home made (not finished yet, I have to change capacitors in crossover).

I like working on floor, so noting falls and gets broken :D
 

Geek

Member
2004-09-08 7:17 am
Hi,

Janez said:
2x PL509 (used), 1x PCL80, 1x 6KR8, 1x 6jz8, 1x PCF802, 1x PF86, 1x PCH200, 1x EBF89, 1x EF183, 2x ECH84 1xECH83 and 2 tubes that have no markings (one looks like EL90, other one looks like EF80 but without perforated mesh for anode).

Except half wave and HV rectifiers this is all I have.

Some of those are great, especially those PL509's for power supplies or power tubes.

Cheers!
 

Janez

Member
2007-11-17 12:49 pm
I belive that PL509 can sound good but the problem is that I don't have any suitable output or power transformers so I would need to buy them and good ones are far from being cheap. Other problem is that they came from old TV-s so I have no idea if they even work.