[nerd1949]

A lot of tube rolling going on, but has anybody changed the output caps? My Indeed came with Elna RJJ's. Not exactly audio quality. I have some SILMICII's and Nichicon MUSE's lying around. It looks like a tight fit diameter wise, but might be possible, and I would have to find some taller posts to raise the top about 1/4 inch. Anybody tried this?

 

[i_djoel2000]

Quote:

Originally Posted by nerd1949 /img/forum/go_quote.gif A lot of tube rolling going on, but has anybody changed the output caps? My Indeed came with Elna RJJ's. Not exactly audio quality. I have some SILMICII's and Nichicon MUSE's lying around. It looks like a tight fit diameter wise, but might be possible, and I would have to find some taller posts to raise the top about 1/4 inch. Anybody tried this?

good idea..but i think you dont need to raise the top, just make a precise neat hole where the caps located, i think its behind the tube amp right?

 

[nerd1949]

No, not the power cap, the two 1000uf signal output caps. They are located near the edge of hte board and larger diameter ones for at least one of them would probably stick about 1/8 inch over the board and to the edge of the plexy, ruling out (I think) cutting a hole. I'd rather just raise it (or find some other, smaller, decent caps).

 

[Nost]

Quote:

Originally Posted by jcoops16 /img/forum/go_quote.gif Is that true of all class A components? As I had music playing through it as I burned my Bravo in, but I didnt need to?

Unlike class AB where one tube/valve amplifies all +ve parts of the signal and another (identical) one amplifies all -ve parts. Class A should (in theory

) burn it's self in as it uses a single valve/tube to amplify both +ve and -ve parts of the signal.

In order to do this, the valve/tube in class A needs to be biased (idealy) @ roughly half it's total voltage (in order to be as linear as possible in its response).

So, (without knowing much about the circuit or the valve/tube data sheet) the valve/tube would be drawing considerable current without a signal applied. Class A is the most inefficient form of amplification because of this.

If anyone has a good reason why applying a signal would help please post, I'm always willing to learn

 

[i_djoel2000]

any suggestion what capacitor to upgrade in indeed tube amp?

 

[Nost]

Quote:

Originally Posted by nerd1949 /img/forum/go_quote.gif No, not the power cap, the two 1000uf signal output caps. They are located near the edge of hte board and larger diameter ones for at least one of them would probably stick about 1/8 inch over the board and to the edge of the plexy, ruling out (I think) cutting a hole. I'd rather just raise it (or find some other, smaller, decent caps).

Whats wrong with the Elnas?

 

[tlau1125]

Quote:

Originally Posted by Nost /img/forum/go_quote.gif My Senn HD515's (50Ohm (budjet but ok)) are quite over powered by this amp and i am in the process of devising an attenuator.

I have the exact same issue with the Alessandro ms1i. I am very interested in the attenuator you are working on. Please let me know what you come up with.

Thanks,
Tony

 

[CPL593H]

Quote:

Originally Posted by Nost /img/forum/go_quote.gif Whats wrong with the Elnas?

Nothing, they are good capacitors. I try to spend more time listening to it and less time worrying about changing glad to happy. I would just mess it up it I started unsoldering stuff like perfectly good capacitors. Likely to lift a pad.

 

[jcoops16]

Quote:

Originally Posted by Nost /img/forum/go_quote.gif Unlike class AB where one tube/valve amplifies all +ve parts of the signal and another (identical) one amplifies all -ve parts. Class A should (in theory ) burn it's self in as it uses a single valve/tube to amplify both +ve and -ve parts of the signal. In order to do this, the valve/tube in class A needs to be biased (idealy) @ roughly half it's total voltage (in order to be as linear as possible in its response). So, (without knowing much about the circuit or the valve/tube data sheet) the valve/tube would be drawing considerable current without a signal applied. Class A is the most inefficient form of amplification because of this. If anyone has a good reason why applying a signal would help please post, I'm always willing to learn

Ah right, I dont understand the theory but thank you for the answer

 

[CPL593H]

Quote:

Originally Posted by Nost /img/forum/go_quote.gif Unlike class AB where one tube/valve amplifies all +ve parts of the signal and another (identical) one amplifies all -ve parts. Class A should (in theory ) burn it's self in as it uses a single valve/tube to amplify both +ve and -ve parts of the signal. In order to do this, the valve/tube in class A needs to be biased (idealy) @ roughly half it's total voltage (in order to be as linear as possible in its response). So, (without knowing much about the circuit or the valve/tube data sheet) the valve/tube would be drawing considerable current without a signal applied. Class A is the most inefficient form of amplification because of this. If anyone has a good reason why applying a signal would help please post, I'm always willing to learn

the tube is in the driver stage, the output stage is mosfet class A

 

[i_djoel2000]

anybody knows how to tweak this beautiful tiny amp to excelently drive AKG K701 or Beyer DT880 600 ohm?

 

[grokit]

Quote:

Originally Posted by i_djoel2000 /img/forum/go_quote.gif anybody knows how to tweak this beautiful tiny amp to excelently drive AKG K701 or Beyer DT880 600 ohm?

The K701s are a very good match with my "rolled" Indeed. I have not had the pleasure of auditioning the DT880s, but they may be too detailed/efficient in the high end from what I have read like my HD600s? Then again they are 600 ohm, so maybe.

 

[i_djoel2000]

Quote:

Originally Posted by grokit /img/forum/go_quote.gif The K701s are a very good match with my "rolled" Indeed. I have not had the pleasure of auditioning the DT880s, but they may be too detailed/efficient in the high end from what I have read like my HD600s? Then again they are 600 ohm, so maybe.

it didnt answer my question. i asked about how to 'tweak' this amp, meaning what kind of modding should give significant sound difference to the amp

 

[nerd1949]

Nothing's wrong with the Elna's, but Elna doesn't recommend using them in an audio signal path. There are better audio quality caps that might offer an improvement for less money than buying a high priced tube, or for that matter, why buy a better tube and mask it with a cap not designed for audio?

 

[Nost]

Quote:

Originally Posted by nerd1949 /img/forum/go_quote.gif Nothing's wrong with the Elna's, but Elna doesn't recommend using them in an audio signal path. There are better audio quality caps that might offer an improvement for less money than buying a high priced tube, or for that matter, why buy a better tube and mask it with a cap not designed for audio?

There's always eBay.ph: 4PCS Nichicon MUSE KZ Audio Capacitor 1000uF 25V NEW (item 250505140694 end time Jan 25, 2010 22:40:50 PHT)

It would be interesting to know the difference, Nichicon do several caps in the "Muse" range. Try "Nichicon muse 1000uf" in google. (interesting, the packaging is aklmost identicle to the Elana's) Also, it seems the RJJ spec is a high reliablity thing. beyond that i have no idea what a cap change might offer.