I want to replace opamps in my DAC that use JRC5532DD right now with LM4562NA. These come with 10MHz and 55MHz speeds. Does it matter witch one to use?

​

Hi All.


I am moved here for the LLC and questions tips. Reason is I am busy with low power, high voltage LLC.

Problems are feedback, resonance amd Lm Q what is best.

Output is 2 x 120 volts 250 mA 1 x 180 volts 250mA (use a voltage doubler here) and 6.3 and 12,6 volts 10 amps.

I do use feedback on the 12,6 volt, but when draw more current the high voltage go quite high, when draw lower it get less high, se need to do something about that.

I have some transformers and hev order also edt 39 and have edt 49 already received.

So now fun, and carefull because of voltages.

Pics here are some sims, the feedback do work, but it is quite dependent of frequency swing, I do not use a pfc,

Hi all which do think would be better an Audiolab 8000c pre or Rotel rc 850

Greetings,

New member, first post and just found out about this lovely community with tons of knowledge.
Long story short, 5 years ago I bought 2x Parasound HCA 2003 and used them for a short period of time until they went back to storage.
Fast forward to today, I will be finishing my Home Theater setup in my basement and will bring back my Parasound from storage.

I always wanted to service them, replace the caps and whatever needs to be done to give them another 20 years of life.
I see that there is an mod upgrade for the HCA 3500 being shared by bigskyaudio which by the way I was always wanted to send my units to them for servicing and always told my self that will do that eventually. I should have done that sooner since Big Sky retired and closed the shop 🙁

My question is:

1. Is there an upgrade mod available for the HCA 2003?
2. Any recommendation on what to do with them? what to change, remove, replace? I will be sending them to a technician in this coming fall.
3. Is the upgrade done on the HCA 3500 similar to HCA 2003?

I love my amps, first high end purchase I did and would love to give them more life.
Any help would be appreciated.


Regards
Manyakus

Hoping someone might be able to help out.
Inherited one of these units with a blown output... the unit has been previously repaired and looks like someone has swapped the original (?) STK4154 to the higher rated STK4164 ..
Wondering if anyone is aware how swap-able these units are with any other STK chips and if anyone can point me in the direction of a source of STK units?

Would like to get the amp back up and running rather than abandoning it to it's own devices in 'the shed'
All help appreciated

Brett

Hello, what about the second configuration (covering the internal bracing holes with sheets of polyfill)?

In theory I'm going to form two aperiodic halved volume chambers (one approaching "sealed", and the other "reflex") separated by a sort of light Variovent (flow resistance but not too much damped, just few centimeters of not compressed polyfill)

Here I found few references with similar idea

I think I'm going to lower the Q of the cabinet and increasing the virtual Vb. Is this correct?
How to model the behaviour?

The Power transformer

my Example is

the Primary is 220 volts (Philippines Base) but you can Deduce it by Dividing by 2.
the Secondary is 12-0-12volts or 0-12volts

we are going to compute specifies 12 volts output with 750ma current (my Example) converting milliamperes to ampere will give us. .75a , multiplying voltage by current gives us wattage or power.

12x.75 = 9 watts


after having solved for the wattage of the transformer, which is 9 watts, look at Tables 1, where 9 watts is listed, follow the table horizontally and pick up the date for the center leg, thickness and turns per volt.


Center leg - 3/4
thickness - 3/4
turns per volt - 10

see at Table 1 and Table 2

the nest step is to compute for the number of turns for the the primary and secondary coils respectively. the number of turns per volts in the primary is equal to the number of turns per volts in the secondary.


Primary coil - 220 volt (PHILIPPINES Base)
Secondary coil - 12 volts
Number of turns (primary) = 220x10 = 2200 turns
Number of turns (secondary) = 12x10 = 120 turns

having computed for the number of turns in the primary and secondary coils. determine the sizes of wire for these coils in the next step . before computing for the guage or size of wire (AWG) must find out the current capacities of wires and their corresponding sizes. this data is provided in table 2 .

the power formula is used again in solving for the currents of wires in the primary and secondary. dividing the watts over voltage gives us the current of the wire:


note:

I = Current, W = Wattage, E = Voltage


I = w/e


I secondary = 9watts/12volts = .75 a
I primary = 9watts/220volts = .04a


after having solved for the currents of wires pick up the corresponding sizes of wires from table 2. choose the closest current listed in the table.


Size of wires (Primary) - #35
Size of wires (Secondary) - #23


in case of a multi-voltage secondary, the higher voltage should be taken for computation. if the transformer has multiple secondary coils, the wattage of each coil is computed and then summed up. in other words, the wattage of the primary is equal to the total wattage of all secondary coils.

if the secondary coil is only center-taped, half of the wattage and current is taken to compute for the wattage of that coil.

the primary is 220-0 volts, the secondary is 12-0-12 volts

Could someone in France or in a neighboring country help me out with two pairs of FRH/FCH20A15 (4 in all, two of each) ?
thanks in advance

Selling some stock I haven't got around to using, at a fraction of their original cost.

Magnequest's EXO-173 phase splitter transformers are very highly regarded. These have the brass channels. There are a host of projects / applications on the internet for them.

$249 for the pair, delivered.

Login to view embedded media This guy bought a farm grade gas/petrol and sawed it in half, then built semi-functional models of the working bits, to show how these nozzles "know" to shut-off when liquid touches their nose. (After 11:30 is an interesting ad but nothing more about nozzles.)

Login to view embedded media Same idea, done not so well (he knows too much), by the guy who makes most of the nozzles in the US.

I also see why we can latch-on with the little lever (here we used to carry a wood wedge) and the nozzle can still shut-off.

Study it before liquid hydrocarbon fuel goes away!

Hi DIYers,

Can anyone recommend a good, not overly expensive ESD mat? I’d like one that’s heat resistant for soldering and about 20” x 20” or wider.

I’m mostly going to be working with discrete transistors op amps.

Thank!

Can you check these like the Ir21844’s ?

I know the pin configuration isn’t the same but wondering if you can check them like that?

The amp I’m working on is a Rockford prime 750-1D

It had full rail voltage across the speaker terminals all outputs test fine but it looks like some has either replaced the outputs or pulled them to check them and soldered them back in

What if we create a local feedback around one of output tubes similar to a paraphase splitter? I have no illusion that I'm the first but I couldn't find any mentions of this circuit. Does it have any major flaws except it will work in class A only?

Can someone identify these speakers? They are pioneer for sure.
There are so many models that look like this from outside but internally different. Please help!

Hello,

I saw i had a 6as7g NOS in my collection and it's honestly just beautiful, might be my favourite looking tube. Definitely at least my favourite looking double triode. So I wanted to use it for a headphone amplifier. Then I saw I had a 6c8g which is the same base so I thought why not put these together? One is a medium mu double triode and one is a low plate resistance double triode, should add up to one headphone amp, right? 😁

Looked around and found this on the Web and was thinking I'd adapt it for an autotransformer volume adjuster and obviously redoing the input stage along with larger value caps to get a better low frequency response. Also want to do a different PSU.

https://www.gammaelectronics.xyz/ax_06-08_tube-headphone-amp.html


Not sure if there are any other glaring flaws in the design i am missing. The input signal to the 6c8g should be around 0.5V(but obv has no drive or I would need an amp 🙂 ) at max volume and the load will be my 50 ohm headphones.

I'm thinking 300V B+ for the 6c8g and 150V for the 6as7g so I can use OA2s(I'd use OD3s for the looks but I've only got two octal sockets and I have a lot of BG7 sockets and equally huge piles of both tubes 🙂 ).

Not sure if I want to do tube rectification or solid state, I'll have to look through my tubes but I don't think I have any that would really be up for the task. I remember having four 6x4 tubes but I think they would be a bit weak for this, right?

Anyway that's what I've got for now, suggestions welcome as I've probably overlooked a few things!

Help me what can really be the problem for the fan not working on my QSC K10 speaker but it's able to play sound only the fan

Just finished recapping my onkyo m504 amplifier.
I noticed that there are provisions on the main amplifier board for additional output transistors. c
Currently the m504 uses 4 output transistors per channel sanken 2sc3856 and 2sa1492
I would like to add an extra pair of outputs transistors making it a total of 6 outputs per channel.
I looked at the prints for the bigger m508 and both amps use the same amplifier board.
The idling current t is even set the same. I know I have to stuff the board with the extra resistors base resistor, and .47ohm collector and emitter resistors.
So here is my question where to get the sanken outputs and how close do they have to match the ones that are currently in there.
There are sanken transistors on ebay but I'm not sure if they are real.
Anyone have any suggestions

We had two JL Fathom f113 subs come into our shop a few months ago. The customer had blown both w7 13" woofers and there is damage on one of the amp boards. The quote for repair for the subs was nearly 2/3 the original cost of the subs so the customer just left them here for us to deal with, so I took them home to try and repair. I was able to get parts for rebuilding the woofers from the guys at Lord of Bass online. I have both woofers rebuilt and installed and amazingly I have one working sub! Unfortunately the other sub had a loud whine as soon as I powered it on. The noise continued after I put it into standby and only stopped after the caps drained. I tested the transistors on the output and 5 out of the 8 were shorted. This is where my knowledge of trouble shooting amps ends sadly. If I can get any advice on how to move forward, I would be most appreciative. Mostly I need to know how to tell if the drive boards are damaged before I install new transistors. I don't have an oscilloscope.

Hi all,

I would like help choosing the correct thermistor/s to place on the primary of my 400va XO. It supplies dual 25vac to 6 lm3875 gain clones, each with 2 x 1000uF caps. Trying to preempt nuisance blowing of fuse. I have several CL60 CL50 CL80 on hand.

Thanks for the help.

Gary

300 watt subwoofer amp with speaker and line level inputs. also has an LFE input if your using it for home theater.

No hum at all. I have had other amps, all of them with hum, but this one is dead quiet.

Controls include auto/standby power, phase, volume, and crossover frequency.

$125 plus shipping.

To all vintage enthusiast & FM experts, I had this unit on my bench for a while now.
When I feed the unit (via Variac) 60 VAC the FM band is perfect, low noise, sensitive station tuning even without an antenna.
No stereo light (sound is only present when pressing the mono button).
As soon as I plug it directly to 120 V there is distortion & noise all across the FM (stations are still there but much lower sound quality & garbled).
AM & all other inputs are working fine.
The 76 Khz signal on PA1001A demodulator is present until the a certain voltage threshold then it disappears.
The majority of the elect. capacitors have been replaced, perhaps it is a power supply issue or one or more components that are failing beyond a certain voltage. Looking for other opinions. Thanks

I'm looking for a service manual and/or circuit description for the B&K ST-140 or ST-140M. I already have a few low resolution versions of the schematic, the minimalist owner's manual, and a one-pager on adjusting bias that applies to multiple amps. I'm not sure if they ever produced a model specific service manual but I'm hoping somebody can help me out. I've split a stereo version of this amp into two monoblocks, and on one of them the bias is low and will not adjust up when trimmed. Looking for insights into the circuit so I can address that. Thanks in advance!

A question for you digital aficionados.
I have been playing around with a Up2Stream board, I note that the supplier offers an optional DAC expansion board (ESS9023) which allegedly improves the sound quality.
Having an old DAC laying around (HIFIDIY 8*TDA1543) I am wondering if it’s possible to bypass the SPDIF receiver chip and connect I2S directly to the DAC, or is something more required?

Looking for 1x LL1638-4H

Anyone have one lying around or can point me to where they have stock?

Amperex MR-123A DHT transmitter triodes, aka FR-123A. Four of them.
Similar specs as 211, 845, trioded 813, etc. 1kV-1500V plates, 10kohm OPT... With minor mods (top cap for plate) these can be rolled in 211 and 845 amps.
These are unused but the boxes rotted away so they have no box. Carefully packed into a relatively solid cardboard box. Ships from Norway, so that is probably coming at 100USD for non EU, and perhaps 50EU for EU.
Will make a great DHT SET amp at roughly 20W output. I just don't have time so want them to find a new home...
Asking 600USD for all four + shipping. OBO...
Compare to new Chinese 845 and 211, or other NOS 211s and 845s on ebay this is a great deal! Besides if I don't sell, eventually I can build an amp with them, I just don't have time for a long while and if good offer (600USD) I will let them go... (I have them on 'bay for 800USD)

Looking to build smallish portable set.

Powered by Bluetooth 2.1 amplifier with batteries .
The idea is to have 2 speakers being joint most of the time to carry around easily but also be able to separate both of them when I want to hear stereo.

So what are some ideas for locking mechanisms to join the two speaker boxes. I am thinking of having a sub that might also be attached at the bottom of the two speakers
The sub I'll probably not carry around too much..
Speaker boxes are around 6x6x 12 each.

The cheapest might be using wellpro to join 2 speakers but was hoping to find something slicker

Is a pair of IRFP150/9150 in class AB possible to operate in 60V rails ?
Thank you

Please, please forgive the newbie amateur post. I purchased some of the red LM4780 boards designed by Peter Daniel and Brian GT many years ago. When I turn on the power, you can hear a soft turn-on thump, but it will not pass signal. I assume the chips are in muted mode. After looking at the datasheet, I am still unclear as to the method of disabling the mute, so the amp stays on. Pins 14 and 20 are the mute pins; do I apply voltage or ground to turn off the mute?

Hi all - just took delivery of a new pair of Faital Pro 10PR320-16 drivers, and was surprised to measure fs at 65 & 68 for the two drivers (out of the box) when spec fs is quoted at 50Hz.

They've come down a bit (both to c 60Hz) after a few hours of burn in - but on last measurement they had both stopped changing.

Is this level of difference (c.20%) from specs normal for Faital drivers? Given I need a pair of 50hz drivers, I am feeling a bit hard done by.

Anyone have any thoughts?

We just discussed ultrasonic noise from Class D amps in a different thread but it would probably fit better here.

It seems people are concerned about Ultrasonic noise polution and I want to have a look into that. So it's about HF noise through your speakers from left over switching frequencies (and every design has some of that).
So I made a few quick measurements with an amp of mine based on Hypex NCore. HF peak is at 70kHz and up to 20uV there, summed from 10-90kHz it's about 600uV. 10-20kHz it's about 19uV (15uV(A)) - so the main part of this is actually HF from 20kHz to 60kHz.

So in my opinion that's absoutely no concern about! Actually you have to search hard for tweeters which will do anything at 70kHz (Bliesma T25B can do this).

But there are so many Class D designs out there - what are your experiences and measurements? How doe ICEpower and Pascal modules do in this regard? Or cheaper chip designs? Any measurements available?

Has anyone reviewed or looked at the new Alpair 7MS or 10M?
Also what are people using for cabinet construction since Baltic birch has disappeared from the Market place?
Rockler has American birch plywood in 3/4" 24"x48" in stock & 1/2" on back order into January- is this a good substitute?

Would the new 7MS work well in the Slim Classic GR dMar-Ken7.3 2v03 cabinet? I used this cabinet for the 7P & it turned out very well. I do keep it out of direct sunlight.
I have 3 sheets of 1/2" Baltic birch I intended to use for the Aplair 7 that I missed buying and now currently unavailable, replaced by the new 7MS.
I veneer 1/4" cherry over the Baltic birch to achieve 3/4" for cabinet density and 3/8" round for the driver opening.

I have not been active on the site since before the Alpair 7 was discontinued & Baltic birch has been hard to find.

Itch'en to start a new speaker project for the Livingroom.

A year ago lost a month apart to the day a father-in-law from Covid & brother-in-law as a collateral death- could not find an open ER due to ER's being too full to see him in time & he bled out from a non Covid health event.


Hope others here have faired better and are in good health.
Thanks in advance. Happy Holidays present & forthcoming....

​

Hello everybody happy thanksgiving ! i have a question about some resistors using in my old speaker ..... I was try to swap some old oxy cable inside and had a chance took out both crossover out of the speaker and found out the manufacture had used two difference brands of resistors in midrange drive section L and R crossovers ......had measure for all the resistors, fortunately they all had the same value , they are in Series 1.3ohm 20w x 3 .. 3.9 ohm total , i feel weird and bad why they did that ?? I think i have to change it. go to the store , the only had 1.2 ohm 20w and 1.5ohm 20w in stock , should i go for it ?? using 2 x 1.2 ohm + 1.3 ohm ?? or go for all 1.2 ohm x3 , sound may be difference ?? please suggest. Thanks .

Hallo gents,

has anyone out there already compared the Telefunken open baffle which can be seen at "glow in the dark audio" by Kevin Davis with the open baffle from the japanese magazin "Stereo Sound" in the artikle "Tube Kingdom" which also can be seen at "je labs" by joseph Esmilla? Regards from germany, Stefan

While browsing through some old Audio magazines I came across this article for an amplifier which uses a three triode phase inverter. Since I like the Van Scoyoc cross coupled inverter, this one stood out. The author has a patent on it (below), but uses a modified version. Here's the article. Thought someone might be interested.

I also saw an amp that uses this version but with type EFP60 secondary emission tubes. I have some of those but no sockets. They're a strange looking loctal style but with 9 pins.

I’m in the process of moving so it’s time to list some excess after figuring out what I’ll need for two speaker builds. Shipping from MA but would prefer pickup for the drivers because I don’t know how well they’ll survive the trip. I have no idea what to price the drivers at so I’ll list them at 75% retail at most, or parity with used market for anything I can’t find new. I would be glad to do bundle offers.


2. Audio Technology 4H520613SD - Works great, just not what I’m looking for (I’m using a similarly sized C-Quenze version). 270 euro each new, listing at $400 $300 $250 $225 for the pair.

3. Audio Technology 6H521706SD - also works great, using the 8 inch version instead. 400 euro each new, $600 $450 $375 $325 for the pair.

4. Usher 8945A - a little dusty but works great. $130 each new, $195 $125 for the pair.

5. Unknown Usher 7 inch - I don’t know what these are. The box says 8836AC but these are definitely paper. The 8836AC was cleared out for $49 each so I can do $80 $60 for the pair if you buy another pair.

6. Scanspeak 21W/8554-00 - Probably needs to be refoamed. I’ve seen people sell them for $200 a pair but if you buy another pair of drivers I can do $125 $100.

Hello, I'm looking for some genuine Supertex DN2540N5-g possibly in EU.

These M2 boards came out of a working amp a couple years back. Just to be safe, I recently inspected, cleaned (some residual flux), bolted them to heat sinks, and tested on the bench...they work fine. They have the Harris 9240s installed. Also, they have Faston 110 spades installed (input, output, ground etc.). I can remove the Fastons if you like. Asking $100 plus shipping. I'll include the Tea Bag PS board as well.

i have some older analog sources i would like to connect to my mixer (portable record players / reel to reel players) that only have speaker outputs.

when plugging these into the mixer, the signal is way to loud and causes a lot of overdrive - and when i turn the volume down enough to get rid of the overdrive i get some sort of tone that drowns out the signal.

so i figure i must need to create some sort of box that i can plug in-between the units to convert the speaker out into a line level out - how can i go about doing this?

can you make a universal box that i could use with all my units (maybe with a pot to determine how much the signal is attenuated?) - or would you recommend modifying all the units internally somehow?

thanks for your help on this

Hey all - a request for a bit of an oddball amp, but I am looking for a Sonab P-4000 in good cosmetic condition.
Just shooting my shot, as unlikely as it is to hit.
Thanks!

Hello. I really need help finding a service manual for the YAMAHA B-4 . Thank you in advance!!!

Due to the cancellation of speaker project, I have for sale 4 SB Acoustics Satori MW16P-8 speaker drivers. All speakers units are like new, used only for few tests. Selling in pairs only.

Price: SOLD

Not responsible to any import duties, taxes, customs fees!

Hi,

As I have little knowledge around this topic I would like to ask a question and seek advice.

The system that I am about to buy is made out of these 3 components:

-Onkyo TX-NR 6050 receiver
-KEF - Q Series 6.5" 2-way Bookshelf speakers (pair)
-Audio Technica ATLP60 XBT Bluetooth stereo turn table


1) the receiver model and brand I wrote would work fine with those speakers?

2) the turntable would also run with the receiver I hope. is this fine ?

3) what kind of subwoofer would you recommend that works well with this receiver and speakers?
I checked the nearby stores where I live and these are the available products it seems I can choose from that fits my budget:

Polk Audio PSW108 10" Powered Subwoofer
Polk Audio PSW10 10" Powered Subwoofer, 100W
Klipsch - Reference Series 10" 150W


Thank you all for your recommendation
Cheers

Hi,

I was thinking of a design for the MoFo that that could operate from the Mofo power supply itself. The only problem is the pre amp swing needs to twice that of the MoFo to fully run it. I was looking at using an inductor based as well, similar to the LÁmp Inducted but with negative feedback utilising a IRF610. I was planning on biasing it at about 100mA. The inductor can withstand up 150mA.

Just wanted your opinion on if it would work.

Circuit is as attached.

Hi Everyone

Check out the new RedRoo tube preamplifier at www.redrookits.com

It's a bit non-traditional, but it sounds fantastic.

Phil

Powered up my Luxman T-2 tuner after many years sitting idle. FM works perfectly, but AM reception is gravelly, distorted, and only comes on after brief warmup. Last time I used the tuner, AM was perfect.

Now I've never worked on a tuner, but my gut feel is its an electrolytic capacitor gone bad with age somewhere. Any hints on where to start?

So i had an idea for a 4 layer board designating one layer as shield (or call it earth) layer that will fasten directly to the chassis, and the dc ground plane connecting to this layer at only single point. I can see how the shield layer would benefit pwr and signal traces but for a ground layer perspective wouldnt it just look like an antennae/oppportunity for a lot of parasitic capacitance? And is that actually still benefitial for audio?

For sale: J313 matched quad
They are matched for Vgs at Id=40mA. They are genuine Toshiba parts.
$50/set. Should be good Aleph Reloaded?
Shipping to the US:$14, Europe:$12
Please PM me if interested.

Good morning everyone. Some time ago I bought the IFI ZEN PHONO phono preamplifier.
I am satisfied with its performance. If I compare it to other preamps I've had, it seems pretty good.
The only thing I have noticed is its low output level when using the MM selection (36dB), but I have solved it by using its balanced output that adds 6dB of gain.
I have seen that there are power supplies for sale with better features than those that come in the original package and that, according to what they say, improve their performance.
My question is: since it is powered by a 5 volt source (which later becomes +12 -12 volts with an internal switching source), could a 10000 mA power bank be used instead since it also supplies 5 volts?
It would be 5 volts DC pure, without the ripples and interference of the network.
Would it be an improvement compared to the wall wart that it originally brings?
Cheers

Hello everyone

I'm struggling to understand how works a capsule/condenser mic , I would like to design a pream based on the THAT1512 ( see attached )

First question : What kind of stage is there in the body of the mic ? , I mean, is there a pre-preamp just for the capsule ?

In the schematic attached below i guess the capsule is not wired on J1 ?

if i would like to desing a PCB where evething would hold into the body of the mic , a 3 pins XLR would not be enough ?

Thx you for your advices

Hi, first post. Interested in making some small desktop transmission line speakers with a full range driver. Only 300mm high but want to know driver size and recommended spec.
Bit of a transmission line fan owned a couple over the years and have a pair of PMC Twenty 23 now. Never made a speaker before but have built a Bottlehead Crack headphone amp some years back.

WTS: "RARE" NEW OLD STOCK (NOS) GENUINE SANKEN / NEC / TOSHIBA / MATSUSHITA / PECOR
( Sansui / Luxman / Pioneer / Accuphase..etc)

PRICE : Usd $10.00 each (World Wide Shipping included)

Accept Paypal ; vintagerepairparts@gmail.com

Email me to purchase: vintagerepairparts@gmail.com

Thank you, HAVE A NICE DAY.

SANKEN
2SA745 - 6 UNIT
2SA747A - 6 UNIT
2SA744 - 11 UNIT
2SC1403 - 5 UNIT
2SC1116A - 3 UNIT
2SC1116 - 1 UNIT

NEC
2SB539 - 5 UNIT
C2337A - 2 UNIT
A1007A - 12 UNIT

TOSHIBA
2SB531 - 17 UNIT
2SB554 - 20 UNIT
2SB557 - 18 UNIT

PECOR
MJ2955 - 4 UNIT

MATSUSHITA
2SB481 - 39 UNIT @USD6.00 ea

$ logo
2SC2323 - 13 UNIT

MOSPEC
MJ15004 - 1 UNIT

Hey,
I am building a fully active / DSP controlled system, the midrange uses a line array of 6 dedicated mid drivers.
To achieve my target performance each driver models best in a 10 litre sealed box, so far so good!
My question is regarding the cabinet loading of the drivers... What are the pros and cons of 6 individual sealed chambers Vs all 6 drivers sharing one sealed chamber of 60 litres?

Please ignore the better cabinet rigidity using 6 sealed chambers Vs one large box and the corresponding savings in labour and materials.
Thanks in advance!
Alex.

Book by Susan Rogers.

https://gizmodo.com/music-neuroscience-susan-rogers-book-1849801399

https://tapeop.com/interviews/117/susan-rogers/

In the attachment there are some images from PS-PCB's of Pioneer's vintage receivers from the 70'. Main reason therefore is the fact, that no chassis mounting for the TO220 parts was realized - instead this only mounting on a actually too small heat sink.
All images in the web after performed refurbishing procedures show the same result - this means that thermal stress continues to occur during operation. This I don't like.
With the SX-939 I plan to screw the TO220 parts onto the chassis in order to achieve better cooling properties.
Maybe there are user's that have done this in such a kind and can upload images - thank you very much.

I’ve got a pair CDX1-1745 that have been written off that I’d like to experiment with removing the bug screen on.

Anyone know how to do this?

I’d assume all CDX1 drivers are alike in this respect.

I have six 33uf Sonicaps Gen 1 for sale. These currently sell for $97 each. Asking price is $250 plus shipping. Will add pictures later.

Anybody familiar with this seller? I read some opinions that C-core OPTS from Ebay suck big way but with low primary impedance there is a better chance of success methink (but what do I know) .TIA L
https://www.ebay.com/itm/1853730798...1291&msclkid=c4e49141647f180b46c3f24cff39da37

I have a Sugden Audition T, a model without tone control, the board is written on Optima 80. There is a light hum after I play music, hum occurred when there is not a signal. But if I turn on and I don't listen to music there is no hum.
In which direction I should direct my inquiry?

Regards,

Jean

In the process of making my own design with components made in U.S.A as one of my guidelines (hope thats not considered political?) Just got a smokin deal on 12 of these custom ordered eminence 10” (based on delta 10b) with cast frame/altered specs. (see pic below for specs.)
These model in a sealed 2 ft3 box (see pic below for curve) perfectly for 60hz hp and 1400hz(+/-) lp

plan to use them with n314x-8/h14ea combo……and maybe a ported lab12 bass bottom (as in stackable)

Then it dawns on me that these 10” custom specs kindly lend themselves to a TL setup, i’m slightly versed in how they work (have read some Martin King and others stuff) and seeing as how i have enough woofers to make 3 pairs of mtm’s why not try some different stuff and choose/keep whats best for my room and sell the others locally.

So question is can the collective knowledge here help guide me in getting a TL box going? See pic below for what i’m thinking (imagine the tweeter as a horn!)
i need to know the desired bottom limit and then base length on 1/4 wave, is there a way to calculate bottom useable frequency from driver specs? I’ve read (unless i interpreted wrong) that you will get 1/2 as much of driver fs lower? Also port opening needs to be equal to sd of both drivers? Also that tapered works better for resonances but is more complicated to get right?
I read if you taper (big chamber to smaller exit) it needs to be 3:1 so if straight with 3 channels (as in pic) would it go 3-2-1 ratio? And is there a formula for starting/main chamber size?

Thx Bob

Wanted: SE transformer for the 6C33C with armorphous core, preferabel EU, 300 mA or more.

Also welcome information where I can order such a pair (also EU if possible).

br

Helmut

Hi!

I have built some tube amplifiers, so now I want to build a preamplifier!
Preamplifier and linestage is the same thing, right?

This is what I am looking for:
*Low Distortion
*Low output impedance

Then I read about the Aikido 🙂

http://www.tubecad.com/2004/blog0011.htm
http://www.tubecad.com/2005/January/blog0030.htm

So I started with the enclosure:
It's a modified printerswitch in aluminium 🙂






The tubes are 6N1P:s and 5687:s!
But a friend told me, he had bought pcb:s and in the documentation there was another shematic, not the one I found. He is using the same tubes...
His schematic was called "Revision A Line Amplifier" It was a bit different, so I wonder:

Which schematic shall I use?
I want to use the best one! 😉


ps. I don't want to use pcb:s. That's uncool 😉

A truly fantastic sounding amp, designed by Nelson Pass. I'm only selling it since I have another Pass designed amp (VFET), that has more synergy with my system (low power requirements).

This s/200 has the optical bias.

It's heavy so id prefer not to ship.

$1300

(Mods: feel free to move this post if it's the wrong place, it doesn't neatly fit into tube or solid state as it's about the balance between them both!)

Hi everyone, I have the following hifi setup.

Turntable w/ AT440mlb cartridge & stylus
Preamp: Croft Super Micro
Amp: Quad 606mk2

The noise floor is getting quite high and it periodically makes weird crackling sounds. I suspect the valves in the pre have had their day and the 606 could do with recapping (1 of the 4 main caps is different to the others - suggesting it's been half(quarter?)-jobbed at some point before my ownership.

I want to take this opportunity to make any worthwhile modifications to it, specifically:

1. I'd like to match the Output Sensitivity of the Pre to the Input Sensitivity of the Amp.
2. Ensure their is appropriate loading for the stylus
3. Balanced the difference in gain between between the line level inputs and the phono input.

One, is balancing the sensitivities a simple case of matching the numbers together? I keep reading that Croft Pre-amps have a high gain however I can only find the stats online for the Croft Micro 25 which has a states output sensitivity of 0.5mV and the Quad 606's input sensitivity is also 0.5v. So is there anything to do here?

1. https://www.dadaelectronics.eu/uplo...vice-Manuals/Quad-606-Service-Manual-V2.0.pdf
2. (this is for the Micro 25) https://web.archive.org/web/20210922142521/http://www.croftacoustics.co.uk/micro25.html

Two, the AT440mlb cartridge apparently has a recommended load impedance of 47k ohms; I am not an EE person, but according to this schematic the Croft Super Micro has a 47k resister on the phono input - does that mean the pre amp is ideally suited to the stylus as is? What about input capacitance, is that "tuneable"?

1. http://soundmovements.co.uk/diyaudio/Croft_SM_III_circuit.gif

Three, when I play from the phono sources the output level is considerably higher than if I play the same music from a line in source. For all of my sins, this usually a line in from the headphones out of my iPhone for casual/background listening - I promise!

I have no intention of carry out these modification myself, I have an amp tech I have used before - but he tends to do what you instruct him and no more, so I want to be quite specific about the work I want carried out.

Thanks for any advice in advance!

Hello, I would like your opinion on building a tube preamp for my car, this is going in the head console which is something I have never seen before, each parts has to be under $50. So far I've been looking at a few ebay/aliexpress kits, let me know your thoughts, thanks.

Kits so far:
https://www.ebay.com/itm/313757694352?var=612529018280
same kit but on Aliexpress: https://www.aliexpress.com/item/2255799850275299.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8
https://www.ebay.com/itm/325203864221?var=514101376212
https://www.ebay.com/itm/125318368510
https://www.aliexpress.com/item/2251832832888687.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8
https://www.aliexpress.com/item/2251832694961293.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8

Two great drivers with similar pricing and somewhat similar specs: they can both be used for a small fullrange speaker project.

But I wonder if someone compared both?
And also which impedance version(s) ?

Soooo, Witch one is positive? Maybe it's a European thing? In the states Red or a + sign. But Blue?

On the back ofvthe board I notice d14 and d15 rectifiers are burnt up....I tried getting schematics from fosgate but have not heard back from them yet.
Does anyone know which mbra160 rectifiers I need...I've seen a couple of them but need to know the exact part number , a link would be great.

I have a set of Honey Badger boards that I put together. I used it for a few weeks before eventually having a thermal runaway problem. I was told that it simply was not possible with this design and But I'm not able to troubleshoot it myself.

Nothing smoked but it got quite hot. I don't know if any parts got damaged.

Whoever buys it needs to be able to troubleshoot. I haven't tried to use it since having a problem. I also have 12 Panasonic 8200uF caps, and a DIY Audio soft start and DC protection circuit. This was all bought new in 2014. Everything is sold as-is.

Price updated to $150 US shipping included anywhere in North America.

Hi, I am selling the following items. They are used "genuine" parts but in good condition. Most of them are pulls from precision instruments. All op amps are tested before shipping. Shipping is $5 worldwide for up to 50g.

Used parts:
BUF03FJ (TO-99) $5.5ea ->6pcs. DIP converted (including the DIP converter board).
Signetics NE5534A/BPA (DIP) $10ea ->only 4pcs. military grade. very hard to find.
ADEL2020 (DIP) $1.5ea
AD844AN (DIP) $1.5ea ->best for I/V. Read the AD844 thread.
OPA627AU (SOIC) $2.5ea
AD797A (SOIC) $3.5ea
LT1028 (SOIC) $1.5ea ->ultra low noise op amp.
LT1763CS8-5 (SOIC) 20pcs $2ea ->ultra low noise +5V LDO, excellent for digital receivers

NEW TDK C4532C0G1H224J320KA MLCC, 1812, C0G, 50V, 220NF/0.22uF $0.4 ea. Check here
NEW Single SOIC-to-DIP OP adapter 1cm x 1cm (include 8 high quality golden pins from Taiwan) $1 ea.
NEW Dual SOIC-to-DIP OP adapter board 1.2cm x 1.2cm (include 8 high quality golden pins from Taiwan) $1 ea.
*convert two single soic ops into one dip dual op

I've been working on a pair of Omni's. I'm looking for a different listening experience that is closer to the way real natural instruments project sound and use the room. I am willing to post pictures, and test results to share what works or doesn't, hoping for some insight and suggestions to improve it.

The starting point is this simple 2way setup. There were initial problems with them, but I'm enjoying them now, wanting more improvements. I'll post the those issues and my solutions up to where I am now.

Index to versions:
V1 : starting point, LR4 XO, soft dome tweeter with reflector, 32L BR woofer
V2 : circular waveguide with compression driver, 32L ABC woofer, new cones
http://www.diyaudio.com/forums/multi-way/303941-omnidirectional-work-progress-4.html#post5000878
V3 : circular waveguide, 16L BR woofer, new cones
http://www.diyaudio.com/forums/multi-way/303941-omnidirectional-work-progress-10.html#post5051183
V4 : circular waveguide, 16L BR woofer, same cones, new outer shell to reduce diffraction
http://www.diyaudio.com/forums/multi-way/303941-omnidirectional-work-progress-14.html#post5118639
V5 : new 16L sealed chamber, new discs and cones, added notch filters, same drivers as previous, using all previous lessons learned OmniDirectional - work in progress

Hi All,

I have the Exposure 2010s2 integrated amplifier, it's remote controller gone missing and I'm looking for a universal remote controller that can control the amplifier, any suggestion for a remote controller?
Or....I know that some brands use the same remote controller protocol as others, long time ago I had a Marantz NR-1604 receiver that every time that I changed the volume it used to change my Naim Nait XS volume as well, does anyone have an idea if Exposure use the same protocol of another brand ?

Thanks

anyone know why this old 1950's driver was designed like this with a perforated whizzer cone?
was it just a sales gimmick or does this create better sound/response?
Maybe this reduced some unwanted peak in the treble response?

Hi, I've got two venues that I'd love to improve the PA system at, preferably with the same set of speakers (though being modular may solve this). My primary goal is to improve sound clarity. I've only built home-audio and car audio (sq not spl) speakers systems in the past, but have done a medium amount of live-show sound. I'm familiar with hornresp (though not an expert) and the principles of quarter-wave designs.

Space 1: This is an intimate 180-seat theatre with circular wood-panel walls, high ceiling, large stage (at least 30% of the space is the stage), gently sloped and well-padded seating.


I'm involved in putting on some hall-of-fame level acts here, but the house speakers are leaving me wanting.

Space 2: It's an outdoor bandshell (~40ft wide) at a flat grassy park with 100m² of space. The shows here are afternoon events with lawn chairs setup, not densely-crowded, mostly classic rock, blues, and jazz.

Both spaces have rigging available.

So my question is, where to start researching?

Are multi-entry horns the de-facto build around here for sound clarity at volume?

Are there brands or driver lines that are much higher regarded than others?

I'm open to almost any budget plan below ~$4k at this point, and I understand the challenge of the two vastly different acoustic environments. A compact-ish setup would be nice, but certainly not a limiting factor at all. Sound quality is the main goal while meeting the SPL needs of each space.

HELP? Screw Sizes - Krell KSA100S - American Sizes

I am based in South Africa and we use the metric system. I need to contact suppliers to get a couple of screws thats missing from a Krell KSA100S that I am restoring.

How do I communicate the sizes? The fractions are one thing as well as the No. size. But I am concerned about the thread pitch/coarseness?

There is basically a couple of screws missing for each type.

Odd question but any help will be highly valued. I am in a remote area and cannot simply visit a supplier. Africa...

Got my hands on 2 of these. Are they of any use as coupling capacitor on the SSE?

Hi,

I'm using a Linn LK100 (1995) with improved Capacitors on the power supply.
It performed great for a few years and now suddenly started going crazy.

After switching on, it plays great with power and oomph and all. Suddenly after a few minutes it dies out. No sound on Left or right speakers.
Dying out is pretty fast, but no 'click or pop' noise. Just as if someone had switched it off.

Switching it off (via the button) after it stopped playing has no effect, until about ~10-20 seconds after switching it off (pressing the On/Off button) - it suddenly plays for a few more seconds and then dies out.

After measuring, I can say that the Toroid transformer receives the mains power and outputs two +33 VAC (Vs. common ground) voltage.
On the PCB it says '86V' next to it...

Any hint on what I should replace?

I would think that the capcitors on the AC-to-DC (power supply) part which seems to be common for both sides are not working OK.

Any other ideas or directions?

Tube rectifiers often specify the minimum resistance required in series with each rectifier to limit peak current. For a full-wave supply, is the PSUD source resistance for the whole secondary winding or, as with the voltage, one half of the winding?

I have used PSUD2 with Ubuntu for a while now, installed with "PlayOnLinux" . A problem created by Ubuntu imposing the snap version of Firefox is that the PSUD help files are not available from within the program.

Before I place it on ebay, I will ask here. I am willing to part with my favorite rtr. I have digitized all my valuable reels and do not listen to it often enough to keep it. I hate to pack it and ship it, but if someone is willing to pay for substantial shipping charge, since its heavy, no problem. I would prefer if someone picks it up or i deliver within 50 miles of Washington DC. I am in Germantown, MD.
Pioneer RT-707 is in great working shape and sounds awesome. Heads show normal wear for age. One light is out. Belt for counter is worn and needs replacement. Otherise all good. Normal contacts cleaning and you are good to go. These sell anywhere from $250 to $700. Make a reasonable offer and its yours.

I am trying to find an Owners Manual, schematic and Repair Manual for a Krohn-Hite 4300B Oscillator. Anyone know what the difference between a 4300A and a 4300B is? I noticed the circuit board says 4300A.

Hi,

I'm currently working on a PP 807/6AU6 pentode amp with mosfet regulated screen grid supplies. I have some 0D3 VR tubes on the shelves, two in series should provide the desired 150 and 300V reference voltages for the mosfets. I know VR tubes turns into oscillators if they are shunted by caps larger than 0,1uF or so, but would it be correct to assume that this behaviour could be stopped by a big resistor between the tube and the cap as in my LazyCad drawing below? (Please ignore the lack of gate stoppers, protection diodes etc):