Tube or SS Preamp?

[apexaudio]

Hi apexaudio,

I will have a custom transformer from Sowter. Their normal is 3:1 (their type 8940 for AC-coupled line output), however I will order a variant at 4:1.

SOWTER PRE AMP/ LINE AMP TRANSFORMERS

Thank U for information
Regards

 

[boggart dapo]

This SS Preamp I was made in 1990, full complementary simetry, selektor with releys. Tube preamp was made 5 years after.

sir mile can u share the PCB layout,,,

 

[Gost22]

Hi M-r Mile!
How much gain this pre-amp with tube ecc88?
Do you have a project or schematic for quality tube buffer for CD-player with ecc88(6922, 6D8J) or 6N1P, and can with 6n8s.
Thank you for your cooperation!

 

[apexaudio]

SRPP preamp with NFB

 

[Gost22]

Tube buffer with 6n8s(6n7)

Hi M-r Mile!
Is you can offer a tube buffer with 6n8s or 6n7 for CD player?
Thank you Mile and cheers!

 

[apexaudio]

Tube Preamp PCB.

 

[still4given]

Looks interesting. Has anyone built this?

Edit; Will it work with 120V .2a/6.3V 2A? transformer?

 

[apexaudio]

Looks interesting. Has anyone built this?

Edit; Will it work with 120V .2a/6.3V 2A? transformer?

Yes there is many builds of this preamp, sound very good.
Transformer 120V 200mA 6,3V 2A is OK for this preamp.
Regards

 

[still4given]

Hi Mile,

I'm trying to understand the PSU. Looks like the low voltage portion powers IC1 and the tube heater circuit. Doesn't the heater need to be 6.3V and the NE555 needs 12-15V? How can they both work on the same voltage?

Thanks, Terry

 

[apexaudio]

Hi Mile,

I'm trying to understand the PSU. Looks like the low voltage portion powers IC1 and the tube heater circuit. Doesn't the heater need to be 6.3V and the NE555 needs 12-15V? How can they both work on the same voltage?

Thanks, Terry

 

[still4given]

?

 

[nigelwright7557]

For a guitar a tube pre amp is better.
For normal high quality audio I would go for op amps.

Marshall did some "valvestate" amplifiers which had tube pre amp and SS amplifier.
They sound OK but not as good as a full valve amplifier.
Most rock guitarists want Marshall full valve amps for the distinctive sound.

 

[still4given]

I've owned several guitar and bass amps over the years. I never owned one for how Hifi it sounded. Never really liked SS for a guitar. I didn't mind it for bass. I still have a SS bass amp.
This is about learning for me. I've built 4 preamps so far but no tube jobs. I have a Dynaco PAS. I don't use it. I've built 6 Hybrid amps so this should be interesting. Waiting on parts right now.

 

[nigelwright7557]

A cheap alternative to a tube pre amp is a soft limiter.
I have used one since the 1980's and always been happy with it.
It benefits from a treble/presence control after it for lead guitar.
The pot changes the tone type from very compressed to almost clean.

An externally hosted image should be here but it was not working when we last tested it.

 

[still4given]

Hi Mile,

Were you intending to provide an answer for me in post #30?

Thanks, Terry

 

[Vostro]

NE555 works from 4.5V to 16V supply.
The supply circuit here seems to be about 7.2V dc if using a 6V regulator, or 6.2V dc if using a 5V regulator. (+/- 0.2V or so)
The relay also seems to be a lower voltage type, and not a 12V relay

Really interested in your build.
Regards

 

[still4given]

I have it built but I don't have the NE555 yet. I tried testing the PSU part and I'm getting about 7.4V at the tube heater. It is supposed to be 6.3V. Should I use a 5V regulator?

I wish Mile was around.

 

[still4given]

I changed the low voltage regulator to an L7805. The voltage is now 6.2V but it over heats and shuts down. Seems like it is pulling too much current. Any suggestions?

Thanks, Terry

 

[Vostro]

Are you connecting to a valve heater when the 5V regulator over heats,
Is the regulator in a TO220 package, does it have a heat sink,
What is the a.c. Voltage of the secondary supply that part of the supply ?

Regards

 

[still4given]

Yes, the valve heater is connected to the low voltage circuit. The transformer has dual voltages one is 0-120vac and the other is 6.3-0-6.3vac. The regulator is an L7805. TO-220 with a heatsink attached. I tried just using 6.3vac to feed the regulator, but the heater voltage drops to 5v. Then I tried using 13vac and the L7805 overheats and shuts down. I have thought about disconnecting the heater from the regulator and feeding it directly from the 6.3vac but the circuit is supposed to work as drawn.