What can I do with them? 4x 1L4, 1x 6AQ5, 3x 6BQ5, 1x 6SN7

zintolo · 2020-07-19 9:49 pm

Hi,

Opening old boxes in my parents' house I've found the following boxed tubes:
4x 1L4
1x 6AQ5
3x 6BQ5
1x 6SN7

Do you have any suggestion on the possible audio projects I could do with them?

Thanks

planet10 · 2020-07-19 9:57 pm

2 6BQ5/EL84 + 6SN7 could be used to make an SE amp. OPT needs to be about 5k.

dave

zintolo · 2020-07-19 10:49 pm

Thanks planet10!

zintolo · 2020-07-20 9:28 am

I will post a simulation of the 1x 6SN7 + 2x 6BQ5 stereo amp in the following evenings.

I think I can use 2x 1L4 for a stereo preamp (keeping two as spares), or one 1L4 and one 6AQ5 for a small guitar amp.

Any other suggestion is very welcome!

andyjevans · 2020-07-20 11:09 am

Tubes are cheap. I don't quite see why you have to use these tubes and nothing else for a build that will require a lot of time and planning. Am I missing something?

zintolo · 2020-07-20 12:34 pm

Hi andyjevans. I've never written I want to use ONLY them, but I would like to have suggestions to use them.

andyjevans · 2020-07-20 3:58 pm

OK! thanks for explaining.

zintolo · 2020-07-21 10:35 pm

So this can be the SE amp with 6SN7 and EL84.
PS the pmosfet on the cathode is not the right model.

This is the simulation with 2Vp at its input, on 8 Ohm:

Code:

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	8.057e+00	1.000e+00	   -4.83°	    0.00°
    2   	2.000e+03	1.954e-01	2.425e-02	 -104.07°	  -99.24°
    3   	3.000e+03	9.741e-02	1.209e-02	    0.29°	    5.12°
    4   	4.000e+03	7.879e-03	9.779e-04	   67.47°	   72.30°
    5   	5.000e+03	2.293e-02	2.846e-03	  172.02°	  176.85°
    6   	6.000e+03	3.782e-03	4.693e-04	  -95.02°	  -90.19°
    7   	7.000e+03	7.546e-03	9.365e-04	   -9.88°	   -5.05°
    8   	8.000e+03	2.623e-03	3.256e-04	   95.77°	  100.60°
    9   	9.000e+03	2.303e-03	2.858e-04	  159.79°	  164.62°
Total Harmonic Distortion: 2.728697%(2.729385%)

zintolo · 2020-07-21 10:36 pm

Has anyone models for the 1L4 pentode?

Thanks

Kay Pirinha · 2020-07-22 3:10 pm

Most probably not, me thinks, 'cause this tube is from 1940 and doesn't see much use nowadays anymore.
Best regards!

zintolo · 2020-07-22 3:30 pm

Thanks Kay,

I've searched for 1L4, 1F2, DF92 and CV1758 that are all equivalents based on these:
https://www.rsp-italy.it/Electronic...ntents/Mullard Equivalents List 1965 1966.pdf

https://tubedata.wernull.com/other/Mullard/Mullard-Valve-Manual-1951.pdf

...but with no luck. How those models are found? Is there any software around to get those parameters by myself and share it here?

zintolo · 2020-07-22 4:08 pm

Is this reliable?
Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively

Kay Pirinha · 2020-07-22 8:34 pm

Hi zintolo,
the European equivalent to the 1T4 was the DF91, not 92.
Best regards!

zintolo · 2020-07-22 9:53 pm

Thanks Kay, but mines are 1L4s that should be DF92.

Eli Duttman · 2020-07-23 12:05 am

The 1T4 is a remote cutoff type. It's intended for AGC circuitry. The 1U4 is a sharp cutoff type frequently found in AM radio IF service. Comparing the 1U4 against the 1L4 might prove interesting.

FWIW, it seems the key feature of the 1L4 is its built in shield.

zintolo · 2020-07-23 7:47 am

Thanks Eli, I'll try to compare those two pentodes and report here my thoughts to see if they are correct.

Kay Pirinha · 2020-07-23 8:40 am

zintolo said:
Thanks Kay, but mines are 1L4s that should be DF92.

Yes, you're right. Sorry for that. I feel some urgent need to clean my glasses
🙄…
Best regards!

zintolo · 2020-07-23 1:37 pm

Do not worry, you helped me many times!

In order to simplify other people's suggestion, I add here the datasheets of every valve (even the ones well known):
http://www.frank.mif.pg.gda.pl/sheets/127/1/1L4.pdf
https://frank.pocnet.net/sheets/127/6/6AQ5.pdf
https://frank.pocnet.net/sheets/127/6/6BQ5.pdf
https://frank.pocnet.net/sheets/127/6/6SN7GTB.pdf

zintolo · 2020-07-23 11:31 pm

Here it is an update on the SE amp now with different polarization for the 6SN7 and EL84 with 6k6 Ra load. Output is 8 Ohm:

Code:

.step vin=0.2
N-Period=1
Fourier components of V(output)
DC component:-0.00395607

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	8.301e-01	1.000e+00	   -2.52°	    0.00°
    2   	2.000e+03	2.102e-03	2.532e-03	  -98.62°	  -96.10°
    3   	3.000e+03	7.846e-05	9.452e-05	 -177.36°	 -174.84°
    4   	4.000e+03	1.060e-04	1.277e-04	    1.05°	    3.57°
    5   	5.000e+03	3.280e-05	3.952e-05	    8.27°	   10.79°
    6   	6.000e+03	1.157e-04	1.393e-04	 -169.81°	 -167.29°
    7   	7.000e+03	3.552e-05	4.279e-05	 -151.26°	 -148.75°
    8   	8.000e+03	8.820e-05	1.062e-04	   21.78°	   24.29°
    9   	9.000e+03	7.929e-06	9.551e-06	  -60.16°	  -57.65°
Total Harmonic Distortion: 0.254335%(0.263054%)


.step vin=0.4
N-Period=1
Fourier components of V(output)
DC component:-0.00520025

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	1.660e+00	1.000e+00	   -2.52°	    0.00°
    2   	2.000e+03	8.327e-03	5.018e-03	  -95.74°	  -93.23°
    3   	3.000e+03	1.154e-04	6.954e-05	   -3.33°	   -0.82°
    4   	4.000e+03	2.119e-04	1.277e-04	    0.50°	    3.02°
    5   	5.000e+03	8.976e-05	5.409e-05	    7.74°	   10.26°
    6   	6.000e+03	2.065e-04	1.245e-04	 -168.61°	 -166.10°
    7   	7.000e+03	7.988e-05	4.814e-05	 -150.63°	 -148.11°
    8   	8.000e+03	1.788e-04	1.078e-04	   25.57°	   28.09°
    9   	9.000e+03	3.098e-05	1.867e-05	    1.27°	    3.79°
Total Harmonic Distortion: 0.502325%(0.506584%)

.step vin=0.6
N-Period=1
Fourier components of V(output)
DC component:-0.00379257

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	2.487e+00	1.000e+00	   -2.52°	    0.00°
    2   	2.000e+03	1.861e-02	7.482e-03	  -94.82°	  -92.30°
    3   	3.000e+03	9.160e-04	3.682e-04	   -0.46°	    2.06°
    4   	4.000e+03	3.221e-04	1.295e-04	   -6.34°	   -3.82°
    5   	5.000e+03	1.053e-04	4.235e-05	   11.02°	   13.53°
    6   	6.000e+03	2.749e-04	1.105e-04	 -172.64°	 -170.12°
    7   	7.000e+03	1.049e-04	4.215e-05	 -155.60°	 -153.08°
    8   	8.000e+03	2.502e-04	1.006e-04	   19.86°	   22.38°
    9   	9.000e+03	4.484e-05	1.803e-05	  -19.02°	  -16.51°
Total Harmonic Distortion: 0.749395%(0.752470%)

.step vin=0.8
N-Period=1
Fourier components of V(output)
DC component:0.000216416

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	3.313e+00	1.000e+00	   -2.52°	    0.00°
    2   	2.000e+03	3.296e-02	9.948e-03	  -94.06°	  -91.54°
    3   	3.000e+03	2.598e-03	7.842e-04	   -3.20°	   -0.68°
    4   	4.000e+03	3.763e-04	1.136e-04	  -16.25°	  -13.73°
    5   	5.000e+03	1.351e-04	4.077e-05	   18.34°	   20.86°
    6   	6.000e+03	3.766e-04	1.137e-04	 -170.77°	 -168.25°
    7   	7.000e+03	1.192e-04	3.598e-05	  163.92°	  166.44°
    8   	8.000e+03	3.926e-04	1.185e-04	   14.61°	   17.13°
    9   	9.000e+03	9.986e-05	3.015e-05	  -13.87°	  -11.36°
Total Harmonic Distortion: 0.998116%(1.000302%)

.step vin=1
N-Period=1
Fourier components of V(output)
DC component:0.00655962

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	4.134e+00	1.000e+00	   -2.52°	    0.00°
    2   	2.000e+03	5.100e-02	1.233e-02	  -93.66°	  -91.14°
    3   	3.000e+03	5.860e-03	1.417e-03	   -2.98°	   -0.46°
    4   	4.000e+03	6.389e-04	1.545e-04	  -64.91°	  -62.39°
    5   	5.000e+03	1.334e-04	3.228e-05	  121.63°	  124.15°
    6   	6.000e+03	2.842e-04	6.873e-05	  137.79°	  140.31°
    7   	7.000e+03	7.282e-05	1.761e-05	  -62.01°	  -59.49°
    8   	8.000e+03	3.042e-04	7.359e-05	   -8.22°	   -5.70°
    9   	9.000e+03	7.907e-05	1.913e-05	   10.99°	   13.52°
Total Harmonic Distortion: 1.241746%(1.243243%)

.step vin=1.2
N-Period=1
Fourier components of V(output)
DC component:0.0146766

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	4.951e+00	1.000e+00	   -2.53°	    0.00°
    2   	2.000e+03	7.226e-02	1.460e-02	  -93.36°	  -90.83°
    3   	3.000e+03	1.135e-02	2.293e-03	   -1.52°	    1.00°
    4   	4.000e+03	1.147e-03	2.317e-04	  -91.04°	  -88.52°
    5   	5.000e+03	5.505e-04	1.112e-04	  175.44°	  177.96°
    6   	6.000e+03	1.625e-04	3.283e-05	   72.22°	   74.74°
    7   	7.000e+03	2.246e-04	4.536e-05	   -5.44°	   -2.92°
    8   	8.000e+03	2.005e-04	4.050e-05	   39.43°	   41.96°
    9   	9.000e+03	1.609e-04	3.249e-05	   -1.64°	    0.89°
Total Harmonic Distortion: 1.477732%(1.478676%)

.step vin=1.4
N-Period=1
Fourier components of V(output)
DC component:0.023313

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	5.757e+00	1.000e+00	   -2.53°	    0.00°
    2   	2.000e+03	9.524e-02	1.654e-02	  -93.22°	  -90.69°
    3   	3.000e+03	2.155e-02	3.743e-03	   -1.95°	    0.58°
    4   	4.000e+03	2.623e-03	4.556e-04	  -96.29°	  -93.76°
    5   	5.000e+03	2.285e-03	3.968e-04	  175.22°	  177.75°
    6   	6.000e+03	5.535e-04	9.614e-05	   60.68°	   63.21°
    7   	7.000e+03	6.695e-04	1.163e-04	   -3.40°	   -0.87°
    8   	8.000e+03	1.137e-04	1.974e-05	  -26.57°	  -24.04°
    9   	9.000e+03	2.166e-04	3.763e-05	   15.44°	   17.97°
Total Harmonic Distortion: 1.697215%(1.697871%)

.step vin=1.6
N-Period=1
Fourier components of V(output)
DC component:0.0300072

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	6.547e+00	1.000e+00	   -2.53°	    0.00°
    2   	2.000e+03	1.166e-01	1.782e-02	  -93.07°	  -90.54°
    3   	3.000e+03	4.113e-02	6.283e-03	   -2.19°	    0.34°
    4   	4.000e+03	7.038e-03	1.075e-03	  -97.49°	  -94.96°
    5   	5.000e+03	6.727e-03	1.028e-03	  174.59°	  177.12°
    6   	6.000e+03	2.023e-03	3.090e-04	   71.40°	   73.93°
    7   	7.000e+03	1.686e-03	2.575e-04	   -7.16°	   -4.62°
    8   	8.000e+03	5.088e-04	7.772e-05	  -85.92°	  -83.39°
    9   	9.000e+03	1.207e-04	1.843e-05	   80.48°	   83.02°
Total Harmonic Distortion: 1.895480%(1.895898%)

.step vin=1.8
N-Period=1
Fourier components of V(output)
DC component:0.0285851

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	7.301e+00	1.000e+00	   -2.54°	    0.00°
    2   	2.000e+03	1.272e-01	1.743e-02	  -92.80°	  -90.26°
    3   	3.000e+03	8.231e-02	1.127e-02	   -2.60°	   -0.06°
    4   	4.000e+03	2.038e-02	2.792e-03	  -98.40°	  -95.86°
    5   	5.000e+03	1.944e-02	2.662e-03	  173.83°	  176.37°
    6   	6.000e+03	6.338e-03	8.681e-04	   73.88°	   76.42°
    7   	7.000e+03	4.724e-03	6.470e-04	  -10.28°	   -7.74°
    8   	8.000e+03	1.419e-03	1.944e-04	 -102.00°	  -99.46°
    9   	9.000e+03	7.279e-04	9.969e-05	  159.18°	  161.72°
Total Harmonic Distortion: 2.114000%(2.114095%)

.step vin=2
N-Period=1
Fourier components of V(output)
DC component:0.00670644

Harmonic	Frequency	 Fourier 	Normalized	 Phase  	Normalized
 Number 	  [Hz]   	Component	 Component	[degree]	Phase [deg]
    1   	1.000e+03	7.981e+00	1.000e+00	   -2.55°	    0.00°
    2   	2.000e+03	1.143e-01	1.432e-02	  -91.67°	  -89.12°
    3   	3.000e+03	1.714e-01	2.148e-02	   -3.05°	   -0.49°
    4   	4.000e+03	4.742e-02	5.941e-03	 -100.12°	  -97.57°
    5   	5.000e+03	5.301e-02	6.642e-03	  173.90°	  176.45°
    6   	6.000e+03	1.370e-02	1.717e-03	   69.51°	   72.06°
    7   	7.000e+03	1.456e-02	1.825e-03	   -8.13°	   -5.58°
    8   	8.000e+03	1.357e-03	1.700e-04	 -161.11°	 -158.56°
    9   	9.000e+03	2.772e-03	3.473e-04	  175.89°	  178.44°
Total Harmonic Distortion: 2.742556%(2.743101%)

Kay Pirinha · 2020-07-24 2:40 pm

Appears to be very clever with that local NFB by a voltage divider that also sets - and simultaneously stabilzes - the EL84's operating point :cheers:

!
Best regards!

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What can I do with them? 4x 1L4, 1x 6AQ5, 3x 6BQ5, 1x 6SN7

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What can I do with them? 4x 1L4, 1x 6AQ5, 3x 6BQ5, 1x 6SN7

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