I can barely get the volume off 0

[andyrlb]

Hi guys , I hope you’re all keeping safe and well .
I’m loving my current system especially after trying different tubes today BUT IT’S LOUD !! If 6 o’clock on the preamp is zero on the volume I can barely get it to 6.35 with my fm tuner and at about 7 o’clock using my dac ( which has a volume pot )
Aside from the obvious use of attenuators is there anything else I could do/try ?

The system:
Counterpoint sa 3.1 valve/hybrid preamp
Firebottle hybrid monoblocks
Jolida glass fx iii valve dac
Tannoy super red monitor 12x


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[walpurgis]

Sounds like a mismatch between the pre-amp and monoblocks. Speak to Firebottle, Alan may be able to suggest something.

[andyrlb]

Sounds like a mismatch between the pre-amp and monoblocks. Speak to Firebottle, Alan may be able to suggest something.

Ah ok , I wasn’t sure as with schiit Freya it had the opposite effect, with that it would be at 12 o’clock before you could even hear it.

Cheers


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[Lawrence001]

Was it the same with all the valves or have you ended up with a very high gain type? Some of the supposed equivalent valves are not really equivalent at all.

[Pharos]

If this oversensitivity is common to most or all I/Ps then a simple attenuator is all that is needed.

With valve gear it is typically very easy, needing only a series resistor between the high O/P source and the following I/P.
This raises the I/P impedance ' seen' by the preamp O/P and lowers the stress on it, and it is extremely unlikely that you have a long enough O/P lead from the pre to the power amp to cause any loss of top because of cable capacitance.

[Light Dependant Resistor]

This mirrors a similar thread here: https://www.stereo.net.au/forums/topic/304361-quad-909-pre-amp-matching/ that despite good advice, ended still in the wrong choice
being made

If you have good sensitivity at the power amp(s) of 800mv or less for full output, and loading 20k or higher, then passive attenuation is always a much better choice.

[andyrlb]

Was it the same with all the valves or have you ended up with a very high gain type? Some of the supposed equivalent valves are not really equivalent at all.

The preamp came with nos Tesla’s and I’ve since swapped that out for a amperex and the gain has remained the same .
I did wonder if there is such a thing as a low gain tube/valve


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[Light Dependant Resistor]

Indeed there are lower gain models and higher gain models of valve depending on what is already installed. You need though to have pin to pin compatibility in every case, like the 12AX7
https://en.wikipedia.org/wiki/12AX7

"The 12AX7 is the most common member of what eventually became a large family of twin-triode vacuum tubes, manufactured all over the world, all sharing the same pinout (EIA 9A). Most use heaters which can be optionally wired in series (12.6V, 150 mA) or parallel (6.3V, 300 mA). Other tubes, which in some cases can be used interchangeably in an emergency, include the 12AT7, 12AU7, 12AV7, 12AY7, and the low-voltage 12U7, plus many four-digit EIA series dual triodes. They span a wide range of voltage gain and transconductance. Different versions of each were designed for enhanced ruggedness, low microphonics, stability, lifespan, etc.

Those other designs offer lower voltage gain (traded off for higher plate current) than the 12AX7 (which has a voltage gain or A v {\displaystyle A_{v}} A_{v} of 100), and are more suitable for high-frequency applications.

Some American designs similar to the 12AX7:

12AD7 (October 10, 1955 - 225mA heater - low hum)
12AT7 (May 20, 1947, dual 6AB4, A v {\displaystyle A_{v}} A_{v} = 60)
12AU7 (October 18, 1946, dual 6C4,[4] A v {\displaystyle A_{v}} A_{v} = 17-20)
12AV7 (February 14, 1950 - dual 6BC4, A v {\displaystyle A_{v}} A_{v} = 37-41)
12AX7 (September 15, 1947 - dual 6DR4, also like octal 6SL7, A v {\displaystyle A_{v}} A_{v} = 100) dual 12AV6 (6AV6)
12AY7 (December 7, 1948 - A v {\displaystyle A_{v}} A_{v} = 44, for audio preamp use)[5]
12AZ7 (March 2, 1951 - 225mA heater, A v {\displaystyle A_{v}} A_{v} = 60)
12DF7 ( A v {\displaystyle A_{v}} A_{v} = 100, low microphonics)
12DT7 ( A v {\displaystyle A_{v}} A_{v} = 100)
12DW7 [6](First triode: A v {\displaystyle A_{v}} A_{v} = 100, Second triode: A v {\displaystyle A_{v}} A_{v} = 17)
12U7 ( A v {\displaystyle A_{v}} A_{v} = 20, for use in automotive radios on 12-volt plate supply)

Although commonly known in Europe by its Mullard–Philips tube designation of ECC83, other European variations also exist including the low-noise versions 12AX7A, 12AD7, 6681, 7025, and 7729; European versions B339, B759, CV492, CV4004, CV8156, CV8222, ECC803, ECC803S, E2164, and M8137; and the lower-gain low-noise versions 5751 and 6851, intended for avionics equipment."

[andyrlb]

Indeed there are lower gain models and higher gain models of valve depending on what is already installed
https://en.wikipedia.org/wiki/12AX7

"The 12AX7 is the most common member of what eventually became a large family of twin-triode vacuum tubes, manufactured all over the world, all sharing the same pinout (EIA 9A). Most use heaters which can be optionally wired in series (12.6V, 150 mA) or parallel (6.3V, 300 mA). Other tubes, which in some cases can be used interchangeably in an emergency, include the 12AT7, 12AU7, 12AV7, 12AY7, and the low-voltage 12U7, plus many four-digit EIA series dual triodes. They span a wide range of voltage gain and transconductance. Different versions of each were designed for enhanced ruggedness, low microphonics, stability, lifespan, etc.

Those other designs offer lower voltage gain (traded off for higher plate current) than the 12AX7 (which has a voltage gain or A v {\displaystyle A_{v}} A_{v} of 100), and are more suitable for high-frequency applications.

Some American designs similar to the 12AX7:

12AD7 (October 10, 1955 - 225mA heater - low hum)
12AT7 (May 20, 1947, dual 6AB4, A v {\displaystyle A_{v}} A_{v} = 60)
12AU7 (October 18, 1946, dual 6C4,[4] A v {\displaystyle A_{v}} A_{v} = 17-20)
12AV7 (February 14, 1950 - dual 6BC4, A v {\displaystyle A_{v}} A_{v} = 37-41)
12AX7 (September 15, 1947 - dual 6DR4, also like octal 6SL7, A v {\displaystyle A_{v}} A_{v} = 100) dual 12AV6 (6AV6)
12AY7 (December 7, 1948 - A v {\displaystyle A_{v}} A_{v} = 44, for audio preamp use)[5]
12AZ7 (March 2, 1951 - 225mA heater, A v {\displaystyle A_{v}} A_{v} = 60)
12DF7 ( A v {\displaystyle A_{v}} A_{v} = 100, low microphonics)
12DT7 ( A v {\displaystyle A_{v}} A_{v} = 100)
12DW7 [6](First triode: A v {\displaystyle A_{v}} A_{v} = 100, Second triode: A v {\displaystyle A_{v}} A_{v} = 17)
12U7 ( A v {\displaystyle A_{v}} A_{v} = 20, for use in automotive radios on 12-volt plate supply)

Although commonly known in Europe by its Mullard–Philips tube designation of ECC83, other European variations also exist including the low-noise versions 12AX7A, 12AD7, 6681, 7025, and 7729; European versions B339, B759, CV492, CV4004, CV8156, CV8222, ECC803, ECC803S, E2164, and M8137; and the lower-gain low-noise versions 5751 and 6851, intended for avionics equipment."

Thanks for the detailed information, I’m currently searching for low gain 6922 tubes for the preamp.
I’m confident that the preamp is the culprit and NOT the monoblocks as like I said before , when I used the schiit Freya the exact opposite occurred, and the same with my alchemist kraken preamp.


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[hifinutt]

Can you try turning down the volume on the jolida ?

[andyrlb]

Can you try turning down the volume on the jolida ?

Hi Phil , yes that’s what I’m doing when using the dac ( though they do recommend turning the volume to max when using it as a dac )
The main issue is using the fm tuner


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[walpurgis]

If you have a passive pre-amp knocking about, you could bung that between the Counterpoint and Monos as a temporary measure, just so it's all usable.

[JohnJo]

I have a matched quad of Gold Lion 6922s with about 30hrs on them. PM me if you’re interested Andy.

[ovlov854]

Hi Andy. DAC and CDP normally have a much higher output than older and vintage pre-amps can handle. So plug your Tuner into the pre and the DAC into another line in with volume turned down and find your desired level

[ovlov854]

Another possibility is that your pre might have adjustable configureabilty on some of your inputs.
i.e. he might have had 2 turntables and set the tuner input to suit ???
Search the net to get the full specs of the pre

[andyrlb]

I will do mate , thanks again [emoji1303]


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[Firebottle]

Hi Andy, from researching all the images I can find there isn't a quick fix to reducing the gain from the line stage.

Two of the pictures I have found show the balance control wired to the pcb with flying leads, I don't know if this is a replacement control that has been fitted.
If yours is the same see if you can find the value of the VOLUME control in Kohms, then fit a resistor of twice that value in each centre leg/wire coming from the balance control.

This should some attenuation before the line stage valve.

[andyrlb]

Hi Andy, from researching all the images I can find there isn't a quick fix to reducing the gain from the line stage.

Two of the pictures I have found show the balance control wired to the pcb with flying leads, I don't know if this is a replacement control that has been fitted.
If yours is the same see if you can find the value of the VOLUME control in Kohms, then fit a resistor of twice that value in each centre leg/wire coming from the balance control.

This should some attenuation before the line stage valve.

Thanks Alan , I know it’s a noble 50k .

Cheers mate


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