[TrollDragon]

I have seen them described as "gooey & very warm". I tend to agree but have limited experience of tube rolling.

Would you agree with this description ?

Also, does changing the rear tubes (power tubes?) affect the sound ?

Yes I would describe them that way, very euphonic and quite enjoyable.

Changing the output tubes has much less impact on the sound. I've rolled quite a few but always went back to the stock 6H30pi, never bothered with the ones that need an adapter and external heater supply like the 6AS7G etc.

 

[jsk ksj]

Thanks for sharing your experience

 

[mordy]

Thanks for sharing your experience

My experience has been that the power tubes do have a significant impact on the overall sound. The way I think of it is like the rhythm section in a band. You may not always be as aware of it as much as the front players, but it lays the foundation for the entire musical presentation.
The relationship between the driver and power tubes is synergistic; sometimes the power tubes contribute 20% and sometimes 50%. It depends on the tubes and the design of the amp as well.

 

[jsk ksj]

My experience has been that the power tubes do have a significant impact on the overall sound. The way I think of it is like the rhythm section in a band. You may not always be as aware of it as much as the front players, but it lays the foundation for the entire musical presentation.
The relationship between the driver and power tubes is synergistic; sometimes the power tubes contribute 20% and sometimes 50%. It depends on the tubes and the design of the amp as well.

Thanks. I'm happy with my set up for now, but do have a volume imbalance between left and right channels. This swaps channels as I swap over the rear power tubes. I can adjust the balance on Uapp, so ok for now.

 

[mordy]

Thanks. I'm happy with my set up for now, but do have a volume imbalance between left and right channels. This swaps channels as I swap over the rear power tubes. I can adjust the balance on Uapp, so ok for now.

Did you try with another set of power tubes to make sure that the source of the imbalance is the tubes and not the amp?

 

[jsk ksj]

I don't have any other power tubes. Can you recommend a cheapish set to try. I don't know what type are installed now tbh.

I have had the amp for about 2 months, but I think the imbalance has only been there for the last week. I did replace the front tubes about a week prior to this. I have examined all the tube prongs and all are clean & I think I have reseated them correctly.

Sound quality is very good, just slightly out of balance.

 

[barbazz]

The relationship between the driver and power tubes is synergistic; sometimes the power tubes contribute 20% and sometimes 50%

That's exactly my experience with opamps in my LD 1+.

 

[jsk ksj]

Doh!

I had forgotten that I had a play with the gain switches when replacing the tubes. Whilst I flipped them correctly, I may have disturbed something.

Anyhow, I have just given them all a wiggle, on off on off, and then think the imbalance has gone. Touch wood.




Nope. Imbalance still there. Oh hum.

 

[jsk ksj]

At the risk of being a pest....

One further observation, the imbalance only occurs after the amp has been on for about 30secs, very odd. Suddenly happens.

 

[TrollDragon]

At the risk of being a pest....

One further observation, the imbalance only occurs after the amp has been on for about 30secs, very odd. Suddenly happens.

If the imbalance follows the tube it's the tube... You really need to pick up a pair of replacement output tubes.

 

[jsk ksj]

If the imbalance follows the tube it's the tube... You really need to pick up a pair of replacement output tubes.

What am I searching for, I really don't know

 

[Cognomen]

With all this conversation about 6HM5 couldn't resist plugging them in. A perfect companion to the Portuguese Summer

I don't have any other power tubes. Can you recommend a cheapish set to try. I don't know what type are installed now tbh.

I have had the amp for about 2 months, but I think the imbalance has only been there for the last week. I did replace the front tubes about a week prior to this. I have examined all the tube prongs and all are clean & I think I have reseated them correctly.

Sound quality is very good, just slightly out of balance.

..

With all this conversation about 6HM5 couldn't resist plugging them in. A perfect companion to the Portuguese Summer

Hot!

 

[Cognomen]

My experience has been that the power tubes do have a significant impact on the overall sound. The way I think of it is like the rhythm section in a band. You may not always be as aware of it as much as the front players, but it lays the foundation for the entire musical presentation.
The relationship between the driver and power tubes is synergistic; sometimes the power tubes contribute 20% and sometimes 50%. It depends on the tubes and the design of the amp as well.

I often find differences between power tubes that are plug and play or just need adaptors as subtle. It's not always the case, though. While I have not experimented with outboard power supplies and breadboards, I feel I have two extremes in my collection. I find the 6H30pi lean sounding with a skosh less bass and skosh of extra treble. At the other end of the spectrum I find the Raytheon 5687 a full sounding juicy power tube with extra bass. I wonder if they would complement each other if one or the other was used as a power tube and the other as a triode driver on a breadboard using an outboard power supply. Instead I could also experiment with drivers that are plug and play or need adapters. For example, I find the Lorenz C3G rather dark sounding so it might sound good with a lean power tube with a bit of extra treble. As for the full sounding juicy one with a bit of extra bass, I wonder how it would sound with a driver that I enjoy but find a bit lean such as the RCA 6GM6. Is it just about almost impossible to predict, though, due to the effect of too many other variables such as circuitry and headphone/speaker response?

 

[TrollDragon]

What am I searching for, I really don't know

6N6P or 6H30pi work fine.

 

[jsk ksj]

6N6P or 6H30pi work fine.

Thanks. I expect I need a matched pair?