DIY audio: what are you building?

[mwhouston]

11 minutes ago, Muon N' said:

I had shaky hands until recently, was nervous tension.

How did you fix it, with high tension (HT)?

[Guest Muon N']

17 hours ago, mwhouston said:

How did you fix it, with high tension (HT)?

Lube!

 

No....will PM

[mwhouston]

Ever seen this.

[F18]

Technically 300B was never made for audio.

[mwhouston]

Just look at the images.

 

https://www.fidelity-magazin.de/2019/06/07/die-muenchener-messen-2019-lautsprecher/

 

Edited June 10, 2019 by mwhouston

[Guest Muon N']

17 hours ago, mwhouston said:

Just look at the images.

 

https://www.fidelity-magazin.de/2019/06/07/die-muenchener-messen-2019-lautsprecher/

 

Groovy

 

[mwhouston]

This popped up on my Facebook memories from a few years back. One of three Bottlehead tube HP amps I built for others. This one has an upgrade kit which uses transistors to provide a regulated HT source. Personally I would have left it as the base kit but the purchaser wanted to go to the next level. The cct. brds. are quite fiddly but the rest is easy. Well for me. 

[mwhouston]

Completed. The engraving (name plate) is due to picked-up.

 

I made it really hard on myself here building this smaller than I have in the past. Both the enclosure and especially the the tiny bit of Vera-brd. To fit the large parts, phone sockets and battery pack this was the only way I could do it.

 

I couldn’t use a 9V battery which would have saved some pace because the PT2308 has a max VDD of 7V. Oatley use this chip and add either a 5V three pin reg or a 5V chip reg. Firstly you are losing battery power in the reg and secondly there is a little loss in head room at the lower voltage. You could lift the reg ground with a diode but then you add noise and still battery power loss.

 

Best solution is 6V battery setup as here. Also with a capacity of around 1000mAh for cheap alkalines  and a draw of 7.8mA I will get well over 100hours of play between battery replacement. Slip in some Lithium AAAs and you’ll forget which century you changed the batteries. 

 

Al foil lines top and bottom and is earthed for shielding and a Dacron pad helps control resonance. It sounds glorious and now getting some hours to burn in all parts  mainly caps. Caps are NP and LESR. Chip is the PT2308. Wiring is silver plated fine copper and solder WBT silver. Safe on with input phone socket switch to cut battery supply when nothing plugged in. 

[mwhouston]

Can some one help me track down this member. I think he may have gone by the name  “Whitelotus”. He bought a tube HP amp from me “Sanctorum” a few years back. He also reviews headphones.

 

I would like him to borrow my latest hybrid HP amp “LeManja” to gain his opinion of its performance.

 

http://retro-thermionic.blogspot.com/2019/05/lemanja-hybrid-tube-and-chip-headphone.html

 

Thanks in advance. 

 

 

 

Edited June 14, 2019 by mwhouston

[Ihearmusic]

Nothing wrong with a bit of free self promotion!

[Guest Muon N']

Hope he went well in his other past time, always wondered.

[Guest Muon N']

On 14/06/2019 at 5:50 AM, mwhouston said:

Can some one help me track down this member. I think he may have gone by the name  “Whitelotus”. He bought a tube HP amp from me “Santorum” a few years back. He also reviews headphones.

 

I would like him to borrow my latest hybrid HP amp “LeManja” to gain his opinion of its performance.

 

http://retro-thermionic.blogspot.com/2019/05/lemanja-hybrid-tube-and-chip-headphone.html

 

Thanks in advance. 

 

 

 

Name changed to @Jensway

[mwhouston]

1 hour ago, Muon N' said:

Name changed to @Jensway

Thanks.

[mwhouston]

The finished HP amp - “retro-2308”

[Jensway]

On 14/06/2019 at 10:50 PM, mwhouston said:

Can some one help me track down this member. I think he may have gone by the name  “Whitelotus”. He bought a tube HP amp from me “Sanctorum” a few years back. He also reviews headphones.

 

I would like him to borrow my latest hybrid HP amp “LeManja” to gain his opinion of its performance.

 

http://retro-thermionic.blogspot.com/2019/05/lemanja-hybrid-tube-and-chip-headphone.html

 

Thanks in advance. 

 

 

 

 

Right here mate.

 

Super keen on this. I'll shoot you a PM.

[Guest Benjet]

 
Right here mate.
 
Super keen on this. I'll shoot you a PM.

I’ll be happy to do a review as well [emoji106]

[mwhouston]

20 minutes ago, Benjet said:

I’ll be happy to do a review as well

Benjet would you like the new PT2308 portable to review. Cheaper to post which I’ll cover both ways. Would you mind mate? 

[mwhouston]

On another note I have been making platted three wire pure silver wire interconnects for years and years. Anything from 1m to 1/2 m. 

 

While the meter was out I tested the leads for capacitance unloaded. 

 

My 900mm “Silver Highways” which have three platted wires, two earths with one copper but only one earth at the termination end. 

 

900mm were 100nf. The smaller ones and a slightly different twist were down to 56nf. I think that’s good, 

 

I was was given some Van der Hull 1m leads which after a few weeks the RCA connections fell off one end. Today I repaired them with some earth first quality RCAs I thought I’d test these. Golly 150nf. 50% more capacitance than mine for the same length. Typical shielded cables. 

 

Cable capacitance is a concern for those with tube gear. That’s why I make my own. No shielding as you may understand shielding but with the platting or twisted and dual earth wire a shielding of sorts. 

[Guest Benjet]

Benjet would you like the new PT2308 portable to review. Cheaper to post which I’ll cover both ways. Would you mind mate? 

I’m in

[PonyTail]

23 hours ago, mwhouston said:

900mm were 100nf. The smaller ones and a slightly different twist were down to 56nf.

 You sure you don't mean pF? Even Cat-6 cable is only around 14pF/FT or 160pF/100m

[mwhouston]

Are you thinking what I’m thinking B1?

 

I have this incredible sounding Grant Fidelity tube based preamp with Jensen copper paper and oil caps. What now if I add a headphone output stage and you can select between preamp output and headphone.

 

With LeManja (headphone hybrid amp with tube and and chip) it was always my intention to have a tube preamp fronting a chip HP driver stage.

 

Elite (pictured) is a high performance extremely good sounding preamp and now (selectable) a headphone amp. 

 

 

 

http://psvanetube.com/wordpress/treasure-6sn7se-globe-a-sound-investment-for-sure/

[mwhouston]

On 16/06/2019 at 3:47 PM, mwhouston said:

On another note I have been making platted three wire pure silver wire interconnects for years and years. Anything from 1m to 1/2 m. 

 

While the meter was out I tested the leads for capacitance unloaded. 

 

My 900mm “Silver Highways” which have three platted wires, two earths with one copper but only one earth at the termination end. 

 

900mm were 100nf. The smaller ones and a slightly different twist were down to 56nf. I think that’s good, 

 

I was was given some Van der Hull 1m leads which after a few weeks the RCA connections fell off one end. Today I repaired them with some earth first quality RCAs I thought I’d test these. Golly 150nf. 50% more capacitance than mine for the same length. Typical shielded cables. 

 

Cable capacitance is a concern for those with tube gear. That’s why I make my own. No shielding as you may understand shielding but with the platting or twisted and dual earth wire a shielding of sorts. 

I was questioned whether I meant nF or pF. Yes it’s pF. Still getting use to my new meter and the capacitance range is one I would use least. So my platted 900mm measured 100pF. That even sounds lower. Just bought some Jaycar 0.5m Concord better RCAs to connect between a preamp and electronic Xover to run my subwoofer at the TV end. They measured 66pF for 0.5m. 

 

While talking leads, in my all DIY system ‘3’ around the TV, I have a tube preamp, chip power amp(60W), EXover and 175W subwoofer. I had my platted leads in and there was always a faint hum. The Mark Audio drivers in the speakers are very sensitive so any small noises are going to be heard. 

 

Usually un-shielded leads aren’t a problem but at the TV end of town every component is on top of the other. The two big toroids in the power amp were radiating into the leads. The Jaycar short lead mentioned above will replace one pair of platted. In my main system all components are at least one foot apart and un-shielded leads work perfectly there. 

[mwhouston]

I posted the idea recently of adding a headphone cct. brd. to drive phones, to Elite. Elite is a tube preamp with the expensive Grant Fidelity Psvane 6SN7 SE LE spheres (globes). Topology is active load or totem pole. An expensive build with premium stepper attenuator, Jensen copper paper and oil caps and external PS.

 

Well the open heart surgery have been successfully competed. And it works like a dream. The HP driver cct. uses the PT2308 HP chip. No need for input caps as the tube section has output caps. It is still a full fledged preamp with two selectable inputs and RCAs out.

 

Sounds really tops and this preamp/HP amp is still up for sale. PM if interested. 

[Guest Benjet]

I posted the idea recently of adding a headphone cct. brd. to drive phones, to Elite. Elite is a tube preamp with the expensive Grant Fidelity Psvane 6SN7 SE LE spheres (globes). Topology is active load or totem pole. An expensive build with premium stepper attenuator, Jensen copper paper and oil caps and external PS.
 
Well the open heart surgery have been successfully competed. And it works like a dream. The HP driver cct. uses the PT2308 HP chip. No need for input caps as the tube section has output caps. It is still a full fledged preamp with two selectable inputs and RCAs out.
 
Sounds really tops and this preamp/HP amp is still up for sale. PM if interested. 

Looks lovely and I bet sounds lovely too [emoji1786]

[mwhouston]

1 minute ago, Benjet said:

Looks lovely and I bet sounds lovely too

You bet it does.