Hagerman Audio Labs Cornet3 User manual

Cornet3
Tube MM Phonostage PCB
Made in USA

CORNET3 Phonostage Kit PCB 2
Copyrights & Trademarks
 Copyright Hagerman Audio Labs 2023. All rights reserved. No part of this document
may be photocopied, reproduced, or translated to another language without prior
written consent.
Disclaimer
The information contained in this document is subject to change without notice.
Hagerman Audio Labs shall not be liable for errors contained herein or for consequential
damages in connection with the furnishing, performance, or use of this material.
Warranty
Hagerman Audio Labs warrants this product free of defects in materials and
workmanship for a period of 10 years. If you discover a defect, Hagerman Audio Labs
will, at its option, repair or replace the product at no charge to you provided you return
it during the warranty period, transportation charges prepaid to Hagerman Audio Labs.
This warranty does not apply if the product has been damaged by negligence, accident,
abuse or misuse or misapplication, has been damaged because it has been improperly
connected to other equipment or has been modified without the express written
permission of Hagerman Audio Labs. This warranty is limited to the replacement or
repair of this product and not damage to equipment of other manufacturers. Any
applicable implied warranties, including warranty of merchantability, are limited in
duration to a period of the express warranty as provided herein beginning with the
original date of purchase and no warranties, whether express or implied shall apply to
the product thereafter. Under no circumstances shall Hagerman Audio Labs be liable for
any loss, direct, indirect, incidental, special, or consequential damage arising out of or in
connection with the use of this product.
Hagerman Audio Labs
1521 Alexander St Apt 1701
Honolulu HI 96822
808-383-2704
www.haglabs.com

CORNET3 Phonostage Kit PCB 3
Description
Congratulations, you have just purchased one of the highest performance-per-dollar
audiophile products available! The Cornet3 delivers high performance on a budget with
a circuit topology features common cathode class-A gain stages with no feedback,
passive equalization, and cathode follower output buffers with constant current sink
loading. Power is supplied by a regulated wall-wart driving a boost converter (running at
about 50kHz) generating the high voltage rail required for proper tube biasing.
Available as a PCB-only kit! You must purchase all other components to complete
assembly.
Specifications
Item Specification
Loading 47k Ohm
Gain 44dB
Output Impedance 1k Ohm
Bandwidth 10Hz to 600kHz
RIAA Accuracy +/-1dB (30Hz to 30kHz)
Noise 77dBA ref 5mV

CORNET3 Phonostage Kit PCB 4
Parts
The following parts (or similar) need to be purchased to complete your kit. Any LED will
work fine. If you plan on using a different case, buy panel-mounted RCA jacks, etc.
Sockets are available from many places (newsensor.com 3x 9PINPCG), along with tubes
(2x 12AX7, 1x 12AU7).
Item www.digikey.com Qty
RCA (red) CP-1419-ND 2
RCA (white) CP-1420-ND 2
Switch 360-2192-ND 1
DC Jack EJ508A 1
LED 67-1072-ND 3
Heat Sink HS372-ND 2
LM555 LM555CNNS/NOPB-ND 1
MUR160 31-MUR160CT-ND 3
2N3906 2N3906FS-ND 1
TIP50 TIP50GOS-ND 2
IRF740 IRF740BPBF-ND 1
50uH 513-1548-ND 2
47uF 25V 565-1306-ND 4
47uF 250V 565-1444-ND 4
470uF 16V 565-3568-ND 4
1nF 495-4761-ND 4
47nF 495-1289-ND 4
470nF 495-1298-ND 7
100 1/4W 100XBK-ND 1
2k2 1/4W 2.21KXBK-ND 1
6k8 1/4W 6.81KXBK-ND 2
220k 1/4W 221KXBK-ND 2
220 1W 13-RSF100JB-73-220R-ND 6
1k 1W 13-RSF100JB-73-1K-ND 18
2k2 1W 13-RSF100JB-73-2K2-ND 6
3k3 1W 13-RSF100JB-73-3K3-ND 2
6k8 1W 6.8KW-1-ND 4
47k 1W 13-RSF100JB-73-47K-ND 2
130k 1W 130KW-1-ND 4
470k 1W 13-RSF100JB-73-47K-ND 5
9R1 3W 9.1AECT-ND 3
Power Supply 1470-3169-ND 1

CORNET3 Phonostage Kit PCB 5
Assembly
 Install all resistors, solder, cut leads. Note the two 10k next to LM555 should be
6k8.
 Install diodes. Solder.
 Install LM555.
 Install power switch.
 Install 1nF and 47nF capacitors.
 Install 47uF (25V) and 470uF capacitors.
 Install LEDs, 2N3904.
 Install RCA and DC power jacks.
 Install sockets.
 Install 470nF capacitors.
 Install TIP50 and IRF740 transistors. IRF740 is next to switch.
 Install 50uH inductors.
 Install 47uF 250V capacitors.
 Break heat sinks in half, right where the hole is (use pliers). File smooth, install
and solder. These act as shields to eliminate noise from power supply.

CORNET3 Phonostage Kit PCB 6

CORNET3 Phonostage Kit PCB 7
Testing
Install tubes. Make sure 12AU7 is towards the front of unit. Apply power to 9Vdc jack.
On power, one LED should light up. After about 45 seconds the other two LEDs light up.
If you have a DVM, check supply voltages on mounting screws.
Troubleshooting
If audio quality is not good, double-check all resistor values to make sure they were
installed into correct locations.

OUT
8
3
1
SENS
6 4 2 5
ENAB TRIG BIAS
7CLMP
U1 LM555
J1
D1 MUR140
L2 50uH
R2 6k8 R1 6k8
C2 470uF
+215V
C3 1nF
L1 50uH
C1 1nF
Q1 IRF740
R3 100
C5 470nF
R4 9.1
R5 9.1
R6 9.1
H1 6V
H2 6V
H3 6V
C6 470uF
R26 470k
S1
D4 MUR140
D5 MUR140
+9V
D3 LED
C16 47uF R28 220k R27 220k
R20 2.2k
+9V
Q3 2N3906
47uF47uF47uF
Hagerman Audio Labs PO Box 61911 Honolulu, HI 96839
16V 16V
3W 3W 3W
25V

J2
V1L 12AX7
R7 47k
R8 1k
R9 1k R10 130k
R23 470k
V2L 12AU7
R17 220
C15 470nF
C14 47uF
+215V
R11 6k8 C7 47nF
R12 470k
V2L1 12AX7
R13 1k
R14 1k R15 130k
R16 3k3 C9 1nF
R19 220
Q2
TIP50
D2 LED
J3
R18 220
C13 470nF
C12 47uF
R25 2k2
R24 6k8
R21 2k2
C11 470uF
R22 2k2
+9V
C10 470nF
C8 47nF
Hagerman Audio Labs PO Box 61911 Honolulu, HI 96839
250V250V
250V250V
16V
+205V+195V
+105V 0.6mA
3.5mA