Upgrade Douk 6p1

[bloo]

Hello
is it possible to upgrade this amp ? i want little more gain or bass.
when i open the amp this is what i see
2x 450V 22uF KMG
2x 50V 220uF NXB
2x 25V 100uF LXV
4x 0.22uf 400V
2x 450V 150u
I heard there is option to upgrade the caps etc..
anybody know if its possible to upgrade and get more gain or bass?
thank you very much

 

[Alllensoncanon]

If you are in US, the best first upgrade for this amp is the power transformer. It will correct all the off bias and filament voltage there by improve both power output and THD. These amp typically came with a 110V transformer and not 120V (9+% off)

 

[bloo]

Thank you,
but im from europe ,here its 220V

 

[Boydk]

Hi bloo...
You need to post a picture/schematic, since all the capacitors you´ve mentioned in post1
are not the way to go or it won´t make any difference. There´s better be some foil caps too. With their values and combined resistor values maybe something can be done. You are certainly in the right forum

 

[JonSnell Electronic]

9% makes no difference as the specification for electrical power is -6 +10%. Filament voltages are rated +- 15% nominally.
Reducing and tailoring the NFB loop will change the gain.
Looks like a 6SN7 is used as the pre and driver, a 6SL7 is slightly higher gain, subject the the schematic employed.

 

[bloo]

Hi
I do not find any schematic for this amp...the only info i found is :
Output power: 6.8W * 2
Frequency response: 20Hz-20KHz
Input impedance: 100 ohms

SNR: 90db
Input Sensitivity: 500mv-2000mv
Harmonic distortion: 1% (1KHz)
Tube: 5z4p * 1 6H8C * 2 6p1 * 4


thank you

 

[Alllensoncanon]

Without a schematic, one could only guess. Looks to me (guess) you have a push pull 6P1(P) output circuit. If that is the case, the + 220uf 50V capacitor should be connected to pin 3 (cathode) of the two 6P1Ps. Parallel to it, could be a 250 ohms 3-4W or so resistor. In that case (circularity), Changing the 220uF and 250R resistor some, can effect the operating point of the amplifier. DO read the "working with high voltage post" (in this forum) before you work on this.

 

[Wavebourn]

Increasing feedback you can get better bass, but worse sensitivity, and vice verse.
If you change rectifier to solid state, you can add one more 6N8S, making 1 more stage per channel for better sensitivity. Such a way you can increase feedback and get better bass.

 

[bloo]

after reading I think the main issue is because my speaker is 85Db sensitivity.
changing to higher sensitivity will solved this issue ?
thank you

 

[Wavebourn]

after reading I think the main issue is because my speaker is 85Db sensitivity.

Oh, cr*p!

You need 4 times more power minimum for such speakers. Increased sensitivity would not help.

 

[Alllensoncanon]

Or changing to higher sensitivity "Speakers" would help. Something like 90db+. Not doing that, consider a push pull Class AB EL34 amp instead.

 

[bloo]

Next week i will get the Klipsch RP-160M they are 97db
i hope it will be better

 

[Wavebourn]

Next week i will get the Klipsch RP-160M they are 97db
i hope it will be better

Wow, it will be overkill. 92 dB would be plenty for your amp.

 

[huggygood]

Thank you,
but im from europe ,here its 220V

measure also your mains voltage.
I am also in Europe and supposed to be around 220v but I am more often between 240 e 250Vac which poses problem for the primary of the transformer of power and on the tension of heating.
I bought a lot of voltage LEDs with direct display on the net, so I can read my line voltage live and I think you will be surprised!
at home, low voltage = 224Vac
high voltage = 253Vac, I live in the city

 

[PRR]

...my speaker is 85Db sensitivity. ...

An old guide is that a home hi-fi should deliver 108 dB SPL on peaks.

For 85dB rated speakers, this needs 200 Watts.

Or a 2*6.5W amplifier with 85dB SPL speakers will give 96dB SPL peaks. "Comfortable listening level" of 85dB SPL long term average has only 10dB headroom for peaks which may reach 15dB-18dB, so will clip ("fuzz") the loud parts. Another 6dB, 4X the power, will make a major difference. Ot aim for 85+6= 91dB SPL speakers, which will play pretty-OK on 2*6.5W.

 

[vinylkid58]

An old guide is that a home hi-fi should deliver 108 dB SPL on peaks.

Never seen that figure quoted anywhere. I've experienced 105dB peaks (short term), and that hurt my ears.

jeff

 

[bloo]

So 97dB speakers should be Ok and give me more power for the amp ?

 

[HoMeR_6V6]

So 97dB speakers should be Ok and give me more power for the amp ?

97 dB will be plenty. The power your amp suplies will be the same, the speakers will need less power for more sound.

 

[FlaCharlie]

Next week i will get the Klipsch RP-160M they are 97db
i hope it will be better

OK, I came here from your other thread.

Moving from speakers that are rated at 85 db to ones that are rated 97 db will make a big difference.

How much difference? If you use an amp with twice the wattage with your current speakers the result is a 3 db increase in sound level. Every time you double the wattage you get another 3 db increase. So if you change to speakers that are 12 db more efficient it's the equivalent of doubling the amp power four times.

To put it another way, it would be the equivalent of using your 85 db speakers with an amp that puts out 108.8 watts per channel.

Have you gotten the Klipsch speakers yet?

Don't be in such a hurry to change amps. Use your current amp with the more efficient speakers for a while before making any amp changes.

I'll make some comments on your amp tomorrow.

 

[bloo]

FlaCharlie, thank you very much
i will get the speakers next week