Dynaco PAT-4

 


 


Dynaco's specifications:
Frequency Response:
High level inputs: 0,5 dB from 10 Hz to 100 KHz
Low level inputs: 1 dB from 20 Hz to 20 KHz

Distortion at rated 2 volt output:
THD less than 0,05% (-66 dB) 20 Hz to 20 KHz
IM less than 0,05%  (-66 dB) with any combination of test frequencies

Hum and Noise:
Phono: 70 dB below a 10 mV reference signal
Line: 85 dB below a 0,5 volt signal

Modification in order to improve performance: (added 2007-05-13)
Replace Q3 with BC549C
Replace Q4 with BC141
Replace all resistors > 47 k with metal film type
After this, THD is about 6 dB lower, no other specs are changed.

Tested data:
1. THD at 1 kHz - Line input
2. IMD - Line input
3. DFD - Line input
4. Frequency response - Line input
5. S/N - Line input
6. Tone control range
7. THD at 1 kHz - Phono (RIAA) input
8. IMD - Phono (RIAA) input
9. DFD - Phono (RIAA) input
10. Frequency response - Phono (RIAA) input
11. S/N - Phono (RIAA) input


THD at 1 kHz - Line input -76 dB = 0,016 %

IMD - Line input -65 dB = 0,056 %

 DFD - Line input -78 dB = 0,013 %

Frequency response - Line input

S/N - Line input A-filter, -90dB

Tone control range


THD at 1 kHz - Phono (RIAA) input -78 dB = 0,013 %

IMD - Phono (RIAA) input -67 dB = 0,045 %

DFD - Phono (RIAA) input -77 dB = 0,014 %

Frequency response - Phono (RIAA) input

S/N - Phono (RIAA) input A-filter

Here is a link to Greg Dunn's Dynaco site with more info about PAT-4