Hi!
I don't lose much. 5mm.
I made a mistake on the link. Here is the correct link.
https://github.com/stefaweb/Q17-a-QUAD405-audiophile-approach/tree/main/Q17-TURBO 1.0/Q17-TURBO-COIL-1.2uH
I'm always looking for different output transistors whenever we have major supply issues with the FQAs.
What do you think of these two?
IXTH52P10P TO-247-3
https://www.mouser.fr/datasheet/2/240/ixyss08994_1-2272188.pdf
IXTH76N25T TO-247-3
https://www.mouser.fr/datasheet/2/240/ixys_s_a0008598113_1-2273007.pdf
I also saw this one more expensive but marked "audio". However, I did not find its equivalent in P-Channel.
IXTH16N10D2 AUDIO TO-247-3
https://www.mouser.fr/datasheet/2/240/ixys_s_a0003807192_1-2272483.pdf
Stef.
I don't lose much. 5mm.
I made a mistake on the link. Here is the correct link.
https://github.com/stefaweb/Q17-a-QUAD405-audiophile-approach/tree/main/Q17-TURBO 1.0/Q17-TURBO-COIL-1.2uH
I'm always looking for different output transistors whenever we have major supply issues with the FQAs.
What do you think of these two?
IXTH52P10P TO-247-3
https://www.mouser.fr/datasheet/2/240/ixyss08994_1-2272188.pdf
IXTH76N25T TO-247-3
https://www.mouser.fr/datasheet/2/240/ixys_s_a0008598113_1-2273007.pdf
I also saw this one more expensive but marked "audio". However, I did not find its equivalent in P-Channel.
IXTH16N10D2 AUDIO TO-247-3
https://www.mouser.fr/datasheet/2/240/ixys_s_a0003807192_1-2272483.pdf
Stef.
Last edited:
Friends,
first I'm going to compose Q17 on the original boards ver. 2.8 (2 pairs).
I noticed that on the printed circuit boards since version 2.5 there are resistors R34, R35, R36, R37 (0R1/2W) but in the BOM on the mouser 3W.
So the question is if 2W will be enough?
Dimensionally 3W metal oxide resistor won't fit much there..., Pitch ideal for 2W metaloxide.
Thank You!
first I'm going to compose Q17 on the original boards ver. 2.8 (2 pairs).
I noticed that on the printed circuit boards since version 2.5 there are resistors R34, R35, R36, R37 (0R1/2W) but in the BOM on the mouser 3W.
So the question is if 2W will be enough?
Dimensionally 3W metal oxide resistor won't fit much there..., Pitch ideal for 2W metaloxide.
Thank You!
Hello!
I have been following this topic for some time as an interested person and it likes it very much.
Since I am not as professional as many, I decided to build a Q17 Turbo.
Stef you wrote that you have PCB-S for sale.
Could I buy 2 pcs from you?
Please contact me because I have only registered in the forum now and I am still under "Moderation" ...
Best regards
Zoltan
I have been following this topic for some time as an interested person and it likes it very much.
Since I am not as professional as many, I decided to build a Q17 Turbo.
Stef you wrote that you have PCB-S for sale.
Could I buy 2 pcs from you?
Please contact me because I have only registered in the forum now and I am still under "Moderation" ...
Best regards
Zoltan
It's a common technique to make assembly/repair easier. I'm not sure it's a great idea, I've seen a few faults where these joints go bad. Usually due to repeated thermal cycling which commonly occurs in amplifiers.
IIRC horizontal bar across end of opanp should be at same end as bar on PCB. Looks ok to me from here, but I'm sure someone else will confirm....
Short answer: Yes, the opamp is placed correctly.
Long Answer: In general, Pin1 can be marked by a circular depression, a laser or printed dot, a printed/lasered bar across the left end or a chamfer down the left side
If you look carefully at the package drawing in the datasheet, you will see the outline of the chamfer on the left side. Now look at your chip/photo and you will see the same chamfer on the left/pin1 side
Long Answer: In general, Pin1 can be marked by a circular depression, a laser or printed dot, a printed/lasered bar across the left end or a chamfer down the left side
If you look carefully at the package drawing in the datasheet, you will see the outline of the chamfer on the left side. Now look at your chip/photo and you will see the same chamfer on the left/pin1 side
Attachments
Thank you all, I finally took another look at the fitted boards from Tibi and got it right.
I would like to stir up the discussion a bit more about non-inductive resistors. Tibi recommends using non-inductive resistors at positions R26, R27, R28.
Resistors made of what material would you recommend as the most suitable for this position? I've looked at the catalogue sheets of various manufacturers, but nobody mentions it...
In the end I will probably choose the carbon ones from TAKMAN.
I would like to stir up the discussion a bit more about non-inductive resistors. Tibi recommends using non-inductive resistors at positions R26, R27, R28.
Resistors made of what material would you recommend as the most suitable for this position? I've looked at the catalogue sheets of various manufacturers, but nobody mentions it...
In the end I will probably choose the carbon ones from TAKMAN.
For those like us, where a cent more or less doesn't matter, metal film resistors are today's standard. These are available in 1% tolerance for 2.5 cents, or in the USA from 60 cents, also very aesthetically available as CMF from Vishay / Dale. However, I could not detect any difference - apart from the appearance.
I also have 1W resistors from Vishay with a metal film, I just don't know if I can use them without concern. Specifically this resistor.
From the BOM in the project guide on github...
R26,28 - 22ohm - https://ro.mouser.com/ProductDetail/Vishay-Beyschlag/ MBB02070C2209FCT00? qs=sGAEpiMZZMsPqMdJzcrNwkfQgWkDJ%252BE2Mwj0n7JK2mo%3D
R27 - 560ohm/1W - https://ro.mouser.com/ProductDetail/Ohmite/OM5615E-R58? qs=sGAEpiMZZMukHu%252BjC5l7YREnR%2FWY87i1xVQq21Ltfa0%3D
Somewhere there's a link to a mouser project you can use for the whole project. But I can't find it ATM.
HTH
Steve
The only resistors that I have found and the manufacturer mentions it in the datasheet (very low inductance) are from Allen Bradley. I will probably order them today.
Allen Bradley resistors
Quantities of these "New Old Stock" carbon composition resistors are limited. Production has now ceased in the USA. Allen Bradley resistors have a huge following of D.I.Y valve hi-fi builders and guitar amp enthusiasts. A huge amount of old manufactured hi-fi were built using these resistors, hence these antique carbon resistors are close to the hearts of many. They were used heavily in vintage Fenders, Marantz, etc. Carbon Composition Resistors particularly those manufactured by Allen Bradley are becoming more scarce and are in high demand due to their unique characteristics. They are known for their very clean and natural sound. Composite resistors differ from film resistors in that they consist of a little tube with a composite carbon resistor material inside. This makes the resistance, so you only have a few mm of material in the signal. A film resistor is made by carving a channel into a carbon (or metal) film on a glass or ceramic tube, resulting sometimes in a few decimeters (feet) of material in the signal! Also a film resistor always has some inductance, composite resistors don't.
Allen Bradley resistors
Quantities of these "New Old Stock" carbon composition resistors are limited. Production has now ceased in the USA. Allen Bradley resistors have a huge following of D.I.Y valve hi-fi builders and guitar amp enthusiasts. A huge amount of old manufactured hi-fi were built using these resistors, hence these antique carbon resistors are close to the hearts of many. They were used heavily in vintage Fenders, Marantz, etc. Carbon Composition Resistors particularly those manufactured by Allen Bradley are becoming more scarce and are in high demand due to their unique characteristics. They are known for their very clean and natural sound. Composite resistors differ from film resistors in that they consist of a little tube with a composite carbon resistor material inside. This makes the resistance, so you only have a few mm of material in the signal. A film resistor is made by carving a channel into a carbon (or metal) film on a glass or ceramic tube, resulting sometimes in a few decimeters (feet) of material in the signal! Also a film resistor always has some inductance, composite resistors don't.