Topic: Pls. Help Antique Sound Lab AV-25 DIY Upgrades

[Villaco]

I have these Monoblocks acquire from a fellow Pdvd member.

UPGRADES DONE:

JJ Vacuum Tubes
Furukawa power cords
DIY Speaker wire courtesy of Remington

Sa mga Masters, any Suggestions to further improve its SQ?

[tony]

what issues are you having with the amp?

[Nelson de Leon]

what issues are you having with the amp?

Alam ko na ang banat ni master Tony. If it ain't broken, don't try to fix it. 

@Villaco:

You can also change the wire used for the speaker connection. Branded capacitors perhaps?

[Villaco]

Medyo bright kasi para sakin kapag na beret na ang singer lalo na sa high volume.  Wala pa kasing budget sa bagong amp. Gusto ko sanang pagawa sayo Master Tony ng Preamp muna kaso, sobrang busy nyo daw at matagal bago matapos. Kaya malamang kay Master Edrel ang bagsak ko nito. Kapag nagpapalit po ba ako ng tranny na gawa ni Sir Edrel kailangan po bang ipadala ko sa kanya ang unit?

[camoteque]

Try tube rolling first. Mas ok kung makahiram muna tubes.

Ano speakers mo? Di kaya speaker ang problema?

[markcrenz]

Medyo bright kasi para sakin kapag na beret na ang singer lalo na sa high volume.

you may need to back up on the volume control when that happens. clipping na yan, no amount of tweak can fix that. if you really want to play loud, use a more powerful amp or more efficient speakers.

Alam ko na ang banat ni master Tony. If it ain't broken, don't try to fix it. 

@Villaco:

You can also change the wire used for the speaker connection. Branded capacitors perhaps?

If it ain't broke, tweak it! 

Kung nangangati talaga sa pag-tweak replace C4/C5 with PP caps and R10/R11 with thin film resistors. And the OPT as mentioned by master tony.

[Nelson de Leon]

you may need to back up on the volume control when that happens. clipping na yan, no amount of tweak can fix that. if you really want to play loud, use a more powerful amp or more efficient speakers.

Pwede din. Or baka yun sibilance siya na-bright.

[Villaco]

Nagyon ko lang napansin sa isang amp na kapag walang power ang pc ko may ugong sya at kapag pinapatay ko ang pc o bubuksan ang pc may thump sound kang maririnig. Ano kay ang problema nito?

[Villaco]

Try tube rolling first. Mas ok kung makahiram muna tubes.

Ano speakers mo? Di kaya speaker ang problema?

Bali 3 na po na brand ng 6L6 & 12AT7 nasubukan ko. So far itong JJ brand ang medyo gusto ko kaso d pa sya fully burn in. Sana lalo pang gumanda after burn in period.

Audio Nirvana Super 8" po speaker ko.

[Nelson de Leon]

Nagyon ko lang napansin sa isang amp na kapag walang power ang pc ko may ugong sya at kapag pinapatay ko ang pc o bubuksan ang pc may thump sound kang maririnig. Ano kay ang problema nito?

Grounding.

[markcrenz]

Nagyon ko lang napansin sa isang amp na kapag walang power ang pc ko may ugong sya at kapag pinapatay ko ang pc o bubuksan ang pc may thump sound kang maririnig. Ano kay ang problema nito?

User. 

The amp should be the last to be turned on and the first to be turned off so the transient noises during startup and shutdown of the source won't get through.

[Villaco]

User. 

The amp should be the last to be turned on and the first to be turned off so the transient noises during startup and shutdown of the source won't get through.

ah ok. Pero yong ugong na wala syang source na naka-on ibig sabihin may problema ang amp?

[Villaco]

Grounding.

Paano po gawin ito sa bahay nyo. parang ang hirap yata nito?

[markcrenz]

ah ok. Pero yong ugong na wala syang source na naka-on ibig sabihin may problema ang amp?

maybe not. read up on "ground loop"

[Nelson de Leon]

ah ok. Pero yong ugong na wala syang source na naka-on ibig sabihin may problema ang amp?

Not necessarily may problem ang amp. They call it "floating" ata. Try mo muna palitan ang ICs mo, minsan nandun ang problem.

[shrek7]

Sir, siguro yung source mo ang bright sounding, just a thought lang.  you've got a very revealing speaker kasi, dont use silver interconnects or speaker wires. JJ have warm sound, baka konting burn in pa ang kailangan.

[Villaco]

Sir, siguro yung source mo ang bright sounding, just a thought lang.  you've got a very revealing speaker kasi, dont use silver interconnects or speaker wires. JJ have warm sound, baka konting burn in pa ang kailangan.

Am using jriver pero kapag binabaan ko ang 25khz sa Musiland ng -10 ok na sya kaso may nawawalang detalye sa audio. Medyo bright nga ang jriver kesa sa foobar kaso parang ang hirap ng User Interface ng foobar. Yong gamit ko na interconnect ang kay Anya618 na RCA.

[Abad Santos 7]

Am using jriver pero kapag binabaan ko ang 25khz sa Musiland ng -10 ok na sya kaso may nawawalang detalye sa audio. Medyo bright nga ang jriver kesa sa foobar kaso parang ang hirap ng User Interface ng foobar. Yong gamit ko na interconnect ang kay Anya618 na RCA.

If I were in your position, I will not modify anything inside the amp.

Without complete knowledge of the circuit design, I think you are in the dark on what
direction to take on the modification. Another thing you will loose the resale value of your
amp just in case you want to upgrade your amp in future.

For me, to make your journey a little shorter, study first the technical details of amp,
speakers, pre-amp, GND Loop, matching impedance, power supply, Class A, Class AB,
SET, push pull...etc.

Then let your ears decide

[Villaco]

If I were in your position, I will not modify anything inside the amp.

Without complete knowledge of the circuit design, I think you are in the dark on what
direction to take on the modification. Another thing you will loose the resale value of your
amp just in case you want to upgrade your amp in future.

For me, to make your journey a little shorter, study first the technical details of amp,
speakers, pre-amp, GND Loop, matching impedance, power supply, Class A, Class AB,
SET, push pull...etc.

Then let your ears decide

Thanks for the input Sir.

[tony]

better sell it na lang...

[Nelson de Leon]

better sell it na lang...

Ano ba yan?!  Palala na ng palala ang mga advices dito.  Gusto lang ma-improve ng unti ng TS, ngayon nauwi na sa bentahan. Hehe! Susunod na advice neto, baklasin ang pyesa at kahuyin. 
















Please reserve pending audition. 

[RXV]

How many hours have you used your JJ tube(s)? I have JJ tubes, they are a little bright but detailed at the beginning, but after a while, it starts to mellow down and then haves a warm character to it. Baka kulang lang sa burn-in yan. I love my JJ's, bang for the buck. But of course, tube rolling doesn't hurt

Also, I find JRiver to be brighter sounding than Foobar nga. Just try Foobar, it's actually the simplest interface (for me) to use, and the best sounding (in my opinion, YMMV).

[Nelson de Leon]

How many hours have you used your JJ tube(s)? I have JJ tubes, they are a little bright but detailed at the beginning, but after a while, it starts to mellow down and then haves a warm character to it. Baka kulang lang sa burn-in yan. I love my JJ's, bang for the buck. But of course, tube rolling doesn't hurt

Also, I find JRiver to be brighter sounding than Foobar nga. Just try Foobar, it's actually the simplest interface (for me) to use, and the best sounding (in my opinion, YMMV).

Yeah. Overall Foobar is best sounding in all genres of music.

[Villaco]

How many hours have you used your JJ tube(s)? I have JJ tubes, they are a little bright but detailed at the beginning, but after a while, it starts to mellow down and then haves a warm character to it. Baka kulang lang sa burn-in yan. I love my JJ's, bang for the buck. But of course, tube rolling doesn't hurt

Also, I find JRiver to be brighter sounding than Foobar nga. Just try Foobar, it's actually the simplest interface (for me) to use, and the best sounding (in my opinion, YMMV).

Nasa mga 70 hours palang seguro plating time ng JJ.

Napansin ko nga yan sa Foobar kaso parang mas maganda sakin ang interface ng jRiver, Tsaka sa ngayaon d ko mapatunog ng maayos ang Foobar.

[geevee]

Try tube rolling first bro....

Try borrowing NOS tubes from other members before attempting to modify your amplifier....

JJ's are bright and since yours have done 70 hours they are probably broken in. But on the brighter side you can always use warm sounding preamp tubes to make the sound more neutral.

[CoolTOYZPH]

You can schedule a tube rolling session with Geevee and I. You bring the ASL and Geevee will bring his magical Vintage tubes. 

BTW, what pre-amp are you using?

[synchro_01]

Medyo bright kasi para sakin kapag na beret na ang singer lalo na sa high volume. 

Master Markcrenz is right. You might be wanting for a certain SPL level in your set up that your amp simply cannot deliver. Beyond its design parameters in output...amps lose coherency and the high frequencies become as what you described...bright.

options
1. lower your expectations with your set up in terms of SPL (free)
2. get speakers with higher sensitivity
3. get a higher powered amp

[tony]

looking at a B+ of just 312 volts, you can try the 7408, 6V6GT, and even the 6EZ5 power tubes,
just remember to re-bias each time you change tubes, 300 to 400mV of bias should do it,
corresponding to 9 or 12 watts of idle tube dissipation....
if you are bold enough, you can go 500mV or even 600mV if the pots will allow you....

for the 12at7, you can try the 12dt8, 12av7, 12ay7, 5935.......

i am modding a pair to run cathode resistor bias so that bias adjustments and red plating will be a thing of the past....
other possible mods is to rewind the opt to run ultra-linear, this way the output stage will be more linear...
still another mod is to regulate the G2 screens to make it stiff, in pentode mode this will make the amp sound better...