Thought I would post the results of many hours spent getting my 5350SE up and running after it sat idle for months with a channel dropout issue. I suspect there are many of these units sitting in garages and storage bins for similar reasons. After all, these amps are now over 20 years old and who knows how many of them are still working. I bought mine new at the Audio Connection in Seattle in 2002 and it has been in daily use since. The takeaway is that the 5350SE can be brought back to life, with the potential of sounding as good, or better, than ever.

Here’s a list of items I completed on the amp, which I believe is the MK I version, which is a little different from the MK II version and I could not find a service manual or parts list:

1. Removed, disassembled and cleaned the Alps input selector switch, REC-Out switch and speaker selector switches.
2. Re-soldered the headphone jack and hot-glued it to the PCB.
3. Replaced all electrolytic capacitors, including the 14 Samwha caps in the power section. For the power section I used Nichicon UKW 50v/2200uf.
4. Replaced the main power transistors (HUF 76639P3) with IRL 2910 (x8).
5. Replaced Q0, Q12, Q100, Q112 transistors (ZVP 331 0A). **This was the source of the channel dropout issue, combined with failing variable resistor VR101.
6. Replaced Q14, Q114 transistors (BP 140-16).
7. Replaced almost all other transistors on the main board (BC 556B, BC 546B, BC550B, BC560C). (This was total overkill, but I had time on my hands and the parts were cheap.)
8. Replaced speaker relays (TE/Schrack #821024) x2.
9. Replaced power resistors (R28/R44) with 0.33 ohm 7W wirewound flameproof (these are the large ones near the heatsink). The old ones looked a little heat-stressed, although they tested OK.
10. Replaced blown fuses with 6.3A T-type (x2).
11. Replaced variable resistors (VR1/VR101) with 50-ohm, multi-turn 64Y type (x2).
12. Cleaned all speaker and RCA terminals, and the AC input jack.

Modifications: Hardwired the pre-amp out/power amp in connection, bypassing the RCA jack and eliminating the U-shaped jumper pins. Replaced the stock rubber feet with solid aluminum feet.

Results: The channel dropout issue is gone and the amp is working properly. It does sound better and by a large margin--perhaps due to the Nichicon KWs, or maybe it was a combination of many things. Music sounds more open, detailed and transparent and bass has more weight and definition. It sounds like a different amp. Even the headphone section sounds better. The improvement is noticeable across all sources and music types. It’s possible the amp may further improve once all the new parts burn in. Channel balance seems improved also—although I have no way to measure it. Anyway, I’m enjoying this amp more than ever and the time and money invested was totally worth it.

Notes: The most difficult task was removing the Alps input selector, which took about an hour of de-soldering work. You need a very hot iron to get all the old solder out. Good to have a variety of tips for your iron as well. After removal, I cleaned all the contact surfaces with acetone, then 1000 grit sandpiper using a light touch and deoxit, followed by some electrical lube.

I adjusted VR1 and VR101 to achieve a drop across CN2/CN102 of 21.5mV. However, this is the spec for the MKII version and the Destiny. I have no idea if the MKI spec is the same. Any input here would be appreciated.

When trying to isolate the channel dropout issue I swapped Q0/Q12 for Q100/Q112. When I powered the amp on it blew the fuses and one of the Mosfets and produced one of the largest smoke plumes I have ever seen coming from an audio component. I thought the amp was toast--literally.

Some of the failing transistors seemed fine when performing a diode check, but were failing nonetheless. I recommend simply replacing them. This applies to the HUFs, the ZVPs and the BPs. Be careful with substitutes since getting the values right is necessary for a stable running amp.

I’ve never had a problem with the ribbon cables, so maybe I’m lucky. If needed, I will replace them with direct wiring, but doing so could complicate things if I have to remove the PCB in the future. I suspect at least some of the issues others have had with channel dropouts, etc may in fact be due to problems with other components noted herein, rather than the ribbon cables. This is after overhauling four different 5350s and never encountering a ribbon cable issue. It is important to clean the connector pins, however.

It is feasible to remove and open the speaker relays for cleaning (I did it successfully). But the plastic covers are glued on and removing them requires cutting through the glue with an x-acto knife. Then you have to glue them back on. Some degree of mutilation is unavoidable. I recommend replacing them if you have any concerns.

I use the Creek in a mostly analog setup including a Rega RP10 turntable, Sony TC-K777esii cassette deck (restored) and KEF LS50 speakers. I’m probably one of the only ones left on the planet who has a use for two tape loops!

Changed power mosfets and output mosfets.
Outputs are 6 IRF640N and 6 IRF9640.
Amp pulls plenty current. IRF9640 gets very hot. With current limiting resistor amp pulls 3amp and giving very clean output.

Dear sound worriers , the attack on your taste's has already started : Login to view embedded media
Their weakest link is their speakers , you can do even better ones for a much lower price!

Dayton Audio gave you some fine audio SiGNaTuRe weapons , please load your sound gunz ASAP before they will kill ya softly 🙂

Greetz!

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As you may know, my dear friend John Busch recently passed away.
https://www.diyaudio.com/community/threads/john-busch-r-i-p.387923/latest
I am helping his family find a buyer for all his audio equipment. John left a storage unit in Kerrville Texas full of woofers, tweeters, speaker prototypes, tube amps, large amounts of crossover parts and big, expensive inductors. Some of it is NIB, some used, some of unknown condition.

EDIT: New photos and new list starting at post #55​

https://www.diyaudio.com/community/...ivers-speakers-amps-parts.388084/post-7117171

These posts will list what I think is in the storage unit that John left behind. I have not been in the storage space, the estimated inventory is based on John's 2018 inventory, recent photos taken my his brothers and some of what John Busch said a few weeks ago.

IMPORTANT! Since there is no one on site who is capable of going into the unit to ship anything, we want to sell this as a lot. We figure out a selling price, buyer takes all.* John wanted to find good homes for his speakers and gear, we hope that someone will be able to take it all, keep what they want and part out the rest to other speaker builders. There is currently no one in Kerrville with audio knowledge or who can ship anything, so I will be your contact point.
* John wanted me to have the pair of P.Audio 18 inch coax and some crossover parts, so those things will be held out of the sale.

What you will see in the next posts are photos of what actually IS in the storage unit. These photos were taken recently by John's brothers. So what you see in the photos is certainly there, although the quantities are uncertain.

NOTE: The Musical Angel 845 is spoken for by someone who can do local pickup. It has been removed from the list.

Yes, I love adventures. I’m a noob (with a little experience) by repairing philips cd players. But I don’t care. As I said, I love adventure. I love risks.

As the seller says, the laser seems to work but cd is not spinning. That’s the only info I have. Price, 120$. Who can resist?

I checked google and I found some threads about the same issue with the same unit.

I’ll update with more info in the next days. First of all, I need the unit in front of me haha.

In summer will be putting on an event for around 200 people in a large barn space, with electronic bass heavy music. Want to buy a small rig or build one. Doesn’t have to be fancy maybe more like a suicide rig.

need help getting a gage of what specs will be needed, what SPL would be needed for that size crowd in a large high ceiling barn.

Would it be best to calculate overall spl or look at spl for tops, mids and subs separately.

has anyone got any recommendations? Budget is around £600 -£800. Have the facilities to build cabinets. Advice on good drivers, amps and boxes to look out for that would fit Into that price would be appreciated.

Any help is greatly appreciated.

Hello. Need assistance from someone id'ing a disk capacitor in an old crossover from 1980's. I spent about an hour last night researching on how to decypher the code on ceramic disk capacitors but never found one like mine. Attached is a photo. Could anyone assist me in ID'ing the specs for this capacitor, value, voltage, tolerance, etc..
Thank you.

I'd like to use a pair of R-core transformers for a Class A power amplifier PSU.

Around 130w per channel dissipation, dual mono, 28V secondaries with additional 18V taps. I'd oversize the transformers, around 500VA per channel.

I understand the primary goes on one bobbin with the secondaries on the second bobbin on the opposite side of the core.

I'm in the UK - 230-250V AC - so in principle I'd prefer UK or EU suppliers. Those I've found include:

James Transformer, China: http://jamestransformer.com/en/transformer/R_core_transformer.html
Yuan-Jing, China: https://www.yuan-jing.com/r-core
Shilchar Technologies, India: https://shilchar.com/ent/product/linear-transformers
Kitamura Kiden, Japan: https://kitamura-kiden.co.jp/r-core/

Has anyone had experience of these or other suppliers?

Any advice or thoughts on specifications or options to request?

Thanks!

John

does anyone out there have a block diagram or any idea of the circuit configuration in a fm acoustics linearizer...? regardless of model i suspect they are the same.. i would REALLY like to see how to achieve frequency manipulation without destroying frequency phase relations in an analog circuit... IF this is truly possible it would mean the end of cable swapping and such tweaks because i highly suspect this is what occurs in the whole cable "sound" phenomena... please any ideas or suggestion for such a circuit?

I picked these up from a friend that is an audio engineer. He said they came out of a regal cinemas which seems kinda strange. The cabinets are homemade, but are really well made with 1.5" thick mdf. The woofers have no labels which makes me think cheap, but everything else from this regal cinemas has been nice stuff so who knows. I just thought I would check to see if they caught anyones eye. They are 18" and have different dust caps, but are the same woofers. If they end up being crap oh well, I didn't pay a whole lot and just got em to mess around with.

Hey guys!

Looking for the last piece to my puzzle as both of my output cards have the same resistor(s) blown/missing.

These are pictured attached as R206, and R211.

The R206 resistor (although blown) reads 3.3k ohm on both cards although I dont trust it. And sadly R211 SMD resistor is missing. Does anyone have any insight as to what these should be? If im not mistaken they help set the output voltage and its the last piece to my puzzle of getting this amp back up and running from a blown power supply section, and quite a few blown output transistors. Im getting beautiful power supply and output operations on my scope, but dont want to install these cards until they are properly functioning 🙂. It looks as if all the transistors on the output cards survived from my testing.

I appreciate all and any help here!

It's been a long time since I had any experiments on the bench and I decided it would be interesting to see what a type 30 could do. So I wired up a simple gain stage with a 10M45 as a plate load and captured a few numbers. Nothing really surprising except for the poor HF frequency response. Later on I plan to use a plate resistor and see how it behaves. Anyhow here's a basic schematic. The filament is lit with DC.




1 volt RMS input


I'm starting to suspect the 100k input impedance of my analyzer is causing the rolloff. While verifying the 50KHz reading I put my bench meter in parallel and it loaded it down further to 5 volts.

I'm a budding DIY audiophile who recently bought a tiny two-seater convertible (BMW Z3) project car. The largest space to install a subwoofer in the cabin is on the floor in front of the seats with the thighs resting on top of it. The space available is about 9" tall, 9" deep, and 18" wide- which is about 0.84 cubic feet.

I'm picturing building a "bass tube" style design similar to this to put right in front of the seats:


I would just buy one of these except for:
1. The enclosure is slightly too tall to fit
2. From what I understand, I could possibly achieve a smaller enclosure by utilizing a passive radiator design.

So now I'm trying to figure out how to design the ultimate daily driver subwoofer to fit with in this small space. I'm picturing an enclosure similar to the one pictured above with an 8" subwoofer on one end, and a passive radiator on the opposite end of the tube.

I'd like to squeeze a lot of power out of this thing so I'm looking at something like the Dayton Audio Ultimax 8" subwoofer and pairing it with something like the Earthquake Sound SLAPS-M8 passive radiator. I understand the passive radiators should displace 1.5-2x the volume of the powered driver and the SLAPS-M8 has 3.5in (88mm) Xmax so I figured that should be plenty.

However: I can't quite figure out the math to see if these would work together.

Dayton Audio recommends this ported enclosure:
Volume: 0.75 cubic ft. (net internal, not including driver or port volume)
Tuned to: 30 Hz
Port: 10" wide by 1" high slot port that is 30" long, which yields an f3 of 30 Hz.

I read that the passive radiators MMS rating should roughly match the weight of the of air within the port volume. If my calculations are correct, the port volume is 300 cubic inches and the weight of that air is about 6 grams.

However, the SLAPS-M8 passive radiator MSS is 75.6g, which seems way off by an order of magnitude. This is surprising to me and I don't really understand where to go from here.

Hoping some of you veteran passive radiator guys can give me some direction, clarification, correction - or maybe just a reality check on this project.

Thanks, guys!

PS: I'm not using any software right now (just home brewed spreadsheets) and am open to any recommendations for software that could aid with this type of design.

The title being an homage to Star Trek TOS.

Conventional audio wisdom says that in most stereo recordings, the low frequencies are mixed to mono. Usually this is stated as anything under 100Hz has been mixed down to mono, therefor there is no need for stereophonic subwoofers. But is this true? I have found that it isn't, and in this thread I will attempt to show that many recordings, be they CD, MP3, or LP vinyl - do have significant stereo under 100Hz.

For a bit of history on this discussion, you can see these two threads:
https://www.diyaudio.com/community/...-ear-really-localize-bass.247583/post-3748187
https://www.diyaudio.com/community/...-subwoofer-system-provide.411881/post-7670252

Using common audio software and common recordings, I'm going to show the stereo content - or lack there of - in many recordings across several genres.
The software used will be Audacity with an M/S plugin, Goldwave for levels and REW for frequency plots. Other software should give very similar results.

Some people here know that I started out building guitar amps as a kid in 60's. In a time long before the internet was even a dream, the only way to learn how guitar amps worked was to take one apart. Anything I found in the trash was usually a hot chassis shocker or a popular 50's vintage amp that was beyond repair. My father decided to upgrade the old Magnavox mono console HiFi to a stereo console and the Maggie became my guitar amp by splicing half of a guitar cable to the wires in the tone arm with masking tape. Oddly the creation sounded pretty good and was plenty loud with a pair of 6V6 tubes driving two or three speakers.

One day the older brother of a school mate who worked at a radio station and was a ham radio operator decided to take his younger brother's Fender Champ apart. We traced out it's schematic and I had a place to start. Several smoking failures later, I had DIYed my first real guitar amp using parts recycled from dead TV sets. Several interim amps were constructed and by the time I was in high school I had a bunch of amp clones both tube and solid state. After a few years of consumer electronics repair I got a job at a Motorola plant where we could get free silicon (within reason) by filling out a sample request form. All my amp builds both HiFi and guitar were silicon based life forms from the early 1970's well into the 1990's.

The Motorola job was my escape from the reality that was running the service department at an Olson Electronics store and living in my parents' house. The separation did not occur on the best of terms and most of my "stuff" was left behind and subsequently discarded. My Hagstrom guitar was stolen sometime in the early 70's so I didn't play guitar at all for a few years. I got a Univox guitar in about 1976 and a dead Kustom amp sometime later. I still have the Univox, but fixed and sold the Kustom within a few years. Several guitars and amps came and went over time, but I never took it seriously and my playing skills have degraded pretty badly. After 41 years at Motorola, I retired and moved north. I gave away the unique Ulraflex / Magnatone guitar amp with two uniquely voiced power amps each feeding a different sized speaker in the combo cabinet due to lack of storage space. I liked the wide range of tones that amp could produce.

Sure I can (and do) stick the guitar cable into the Focusrite and call up any one of several killer amp sims on my PC and jam with some backing tracks from a DAW, but..........

I look around the room and I can see 10 guitars or basses and a few more in pieces, but no real amp. The Hundred Buck Amp Challenge got me to build a few amp prototypes, four of which are pictured here. The little 4 tube unit in the black case is the only one that still works, though the 5 tube unit on the bottom just needs an OPT, as I "borrowed" the one it had.

I have the skill set and knowledge to make just about any amp I want, but I can't make up my mind what that is, so nothing has been built. The music I grew up with and played from age 12 on was 60's surf music, so reverb is a "must have." The little 4 tube 4 watt amp is loud enough in the concrete basement, but falls short outside with my 91 dB speakers, so more power and better speakers are a given. My musical tastes wander from mellow to metal, and I occasionally will beat on a bass guitar, so it's hard to figure out what kind of amp or amps to make.

For another perspective, I looked at all of what's out there today and watched far too many YouTube videos to realize that much of it all sounds the same. The Hughes and Kettner Triamp Mark III looks like the most flexible design out there, but it is $4000! I like, and will likely use the idea of multiple preamps and multiple power amps with relays or other means of switching them. I'm sure that there will be several roadblocks and detours on this journey, but I need to start somewhere.

Obviously, this idea has been kicking around inside my head for quite some time, since I found an unbuilt DIY PC board in my junk box that had a pair of 9 pin sockets, a 1/4 inch jack and places for 6 pots. It had a 2011 date on it so I made this when I was still working at Motorola and living in Florida. A journey through my 10 TB hard drive found a matching Eagle layout with an associated schematic. It looks like a typical 4 stage Fender, Marshall, Vox preamp without a phase inverter, so I must assume that I intended to drive one of my existing amp boards with it, most likely the SPP which uses EL84's. Yesterday I had a nearly empty PC board. Today I have one that is populated, albeit with whatever I could find quickly in between periods of shoveling snow. Now I have a place to start. I will apply power today, in between some more snow shoveling.

Any thoughts or ideas on features to include and comments in general are welcome. If I follow this path wherever it leads me there will likely be more than one amp created. I have created an output stage concept called UNSET that works well for HiFi. It needs to be tried for guitar amp use as well.

Have 4 of these SEAS L26RO4Y woofers in excelent condition. Asking 220 euro each.

https://www.bbc.com/news/health-68921561

dave

Good day all,

I am currently working on design of a PP class A amplifier (power monoblock) with KT88. Switching between UL and triode. Both modes output power max. 20-22W. Now is amp designed without NFB, but in the future I am thinking about introducing a weak NFB 5-6dB. I assume an input sensitivity of at most 1.4-1.5Vrms in Triode mode with NFB 5dB. In the UL mode, the sensitivity is lower. Input only balanced. In attachment is the schematics with assumed values. It is my first PP amp, before i designed only SE. I did not use LTspice when designing. I confess, I don't know how making simulations in LTspice. Until now I always used paint_kip/kit. I also used this program now.
Please, I want to ask you four questions (ranges of questions):

1) Do you think my design is okay? Or did I make some fatal mistake? What do you think of him? I want to avoid unnecessary expenses. And I want to achieve acceptable sound (i know subjective) with acceptable distortion.

2) What ccs do you recommend for Driver? LM334, or do you prefer cascode? Its no problem make a negative supply rail...

3) What ccs do you recommend for Power stage? LM317HV, or do you prefer cascode? I quite like the CCS in the attachment by Walt Jung.

4) Do you think that the ECC81 will be enough to drive the KT88? Either current or voltage? Or should I plan a two-stage driver? I prefer a minimal number of elements in the signal path. It looks fine on paper, but reality can sometimes be more complicated.

Unfortunately, I am not familiar with CCS and their designing and performance, so I am asking for your help with the design of this part of my amplifier.
One more note (I don't know how important it is in the cathode CCS design, but I'll mention it just in case) max. HF for output transformer is 90KHz, and I want to make full use of this frequency band. I am also attaching the designs of the operating points ECC81 and KT88 UL.

Thanks for answers

Hi guys,

I'm working on a 3way design with a 12" woofer, 6.5"mid and 30mm tweeter. I built a nice passive crossover for the mid\tweeter but want to use active to the woofer. For amps I'm using Fosi small format class D. I'm looking for an active crossover that's reasonably priced to be similar in size to the Fosi class D amps.

I usually know of these things I want but for some reason can't find a crossover in the size. I can get great prosound units all day long and have 5 already. If need be, I'll DIY but would like to save the labor.

At this time I don't want DSP, I'm waiting for one more technical generation to get on that bandwagon.

Thanks,

Scott

Does anyone have schematics or information on VTL De Luxe 120 mono blocks or VTL The Ultimate Preamp?

Thanks,
Brandon

This might be the simplest active tone control circuit, but is there a way to modify the gain and frequency response?
The circuit as given gives a gain of +/-20 dB which I think is huge and distorts given today's digital sources with 1vpp output.. Is there a simple way to modify the gain to +/-10 dB?

1. What is the effect of reducing the variable pots 100k to 47k?
2. What is the effect of replacing the Emitter resistor 1k and connecting to ground?

Hi guys,Im looking on a pcb board of Glassware ACF or ACF2.
If someone have this and would sell this plese contact me.Thanks😉

Hi guys!
After few years with Dallas II horns with Fostex FE206EN and super tweeters,i'm looking for more mid range purity. What is your experience with phase plug on this setup,is it worth or not? I still have litlle scare to cut membrane,but if result is worthy,then i will find courage 🙂.
I see also that there are diferent shape and size of plugs avilable. From 35-80 mm long and diferent shapes,from bullet like shape to konus shape. What are diferences and what is the best for mid range purity?
So,any one with experience,please share.
Setup:
DALLAS II with Fostex FE206EN and MONACOR supertweeter
Monoblocks SE with Eimac 100TH
Streamer Rpi based,allo kalli reclocker and i-sabre DAC 9038,powerd trough extra stable linear power plant
Woofer ACE BASS B2-50
Cables:
interconect- quad star 8x0.4mm silverplated coper
speaker- quad star 8x1mm silverplated coper
power-shielded 7x1.5mm squere coper

Everything except woofer is hand made. Woofer with 18" spesker is also in production,so after is finished,hole sistem will be hand made.

Near perfect response with passive filter , nice drivers - well done guys :

https://sbacoustics.com/product/5-satori-mr13tx-4-textreme/

https://sbacoustics.com/product/6½-satori-mr16tx-8-textreme/

Regarding the price - better buy something nearly perfect instead of wasting more money on mediocre drivers year after year and even more money on several cabs!

Crazy hobby - some like to torture themselves , pain must be fun to them 🙂

Who taught you such a luxury lifestyle?

But maybe all this expensive machinery in your garage or hobby room needs a justification?

regards , sawdust is our cocaine 🙂

Our friend @bikinpunk recently reviewed the KEF Blade 2 Meta
Really not much to complain about that speaker. Well, other than the price, that's a bit of stretch goal.

What's interesting is that it answers a question that is posed on sometimes- what happens when we use multiple woofers.

Here's the Reference 1 Meta, which uses a single 6.5" woofer.


Here's the Blade 2 Meta, which uses FOUR 6.5" woofers.



Now what happens at 96dB @1m.
Again, first the Reference 1 Meta:


Blade 2 Meta:



Let's also look at the dynamic range compression tests:
The Reference 1 Meta:


Blade 2 Meta:




How does this compare to a single large woofer?

Here's the JBL 4367, with a single 15" woofer...






www.erinsaudiocorner.com is a treasure trove of hard data like this, and if someone wanted to do a study to see if there was a correlation between distortion and dynamic range compression, there are almost 200 speakers on that website...

Hi guys
I have a Washburn PB30 bass amp with a shorted power transformer, some guy brought it a few day ago, asking me to fix it.
The primary winding (120VDC) seems to be ok but the secondary is shorted. Its supposed to be V-0-V (symmetrical).
I used an 18-0-18 volt transformer that I bought a few years ago for a console but it is way to big for this amp. Anyway, it started the amp right away.
It has a pair of TIP41C / TIP42C power transistors and no additional regulator. Its a quite simple amp design.
I have no clue what the original voltage on this transformer should be, since I cannot find the schematics on the internet.
But I'm quite sure its more that 18VDC.
I know a guy who makes transformers for a living and he would help me out.
So, any ideas?

Hi all,

I am selling 20 pairs of 2SK1529-2SJ200, NOS.
I bought them 10 years ago when I was planning my F5 Turbo and never used. I can sell pairs/quads or all in one lot.



All have been matched in pairs within 0.05V VGS, there are 3 quads matched within 0.02V.
VGS matching has been done static at 500mA with CCS power supply and at 30 Degrees C on transistors.



PM for the price and details.

I live in the Netherlands, I can ship worldwide with PostNL, you can check rates here:
https://jouw.postnl.nl/online-versturen/en-GB/pakket/kiezen

Payment with paypal.

Thanks!
Daniil

I have recently come in to possession of a dual mono mosfet amp from the early 90's
It's a Linx branded amp but I understand it was a small custom production run and doesn't have a model name per se. It appears to be a dual mono version of a Linx Pulsar - regardless, there is little info about these amps online. Linx was a small but well regarded New Zealand amp maker that Wharfedale picked up in the late 80's and then ceased to exist some time in the 90's.

The seller claimed 2 X 280W RMS ino 8 ohms, 450 watts in to 4 ohms which seems like a lot of power. I haven't measured the amp's power output (don't have equipment).

The amp itself is quite heavy (15-20kg?)
Each channel has its own power supply supplying +/- 75VDC.
Each power supply has 2x 10,000uF 75V caps (Sprague Powerlytic 36DE).

There are 4 output devices per channel, marked SML BUZ906D G9418Y and SML BUZ901D R9404Y.
There are 3 small-ish electrolytic caps per channel (2x 47uF 100V, 1x 25v 220uF)
Near each line input there is a polypropylene (?) 5.0+/- 10% 200V SiderealKaps capacitor
There is one potentiometer per channel
I have measured the DC offset at each channel's output, left = 1-2mv (fluctuates), right = 7-9.5mv (fluctuates) (was 20mv at cold turn on)

I fixed a buzzing noise coming through the speakers by re-tightening the star ground nut for each channel, there is now only a faint hiss/hum from each speaker which is only audible with one's ear right against the speaker


I have 4 questions:

1. The heatsinks on the right channel are somewhat hotter than the heatsinks on the left channel. I can rest my hand on the left heatsinks for about 10 seconds before feeling burned, while I can only rest my hand about 2.5 seconds on the right heatsinks before feeling burned.

I am assuming this is because of the higher DC offset voltage. Can I fix this by simply adjusting the potentiometer until I get 0VDC at the speaker terminal? If not how would I go about fixing it?


2. I like the amp's sound but it doesn't seem to have the resolution/soundstage I was hoping for. Are there any ways I can service or modify the amp to increase the sound quality?

I have a few ideas:

• loosen, clean, and tighten any mechanical connections
• replace the small electrolytic caps (there's only 6 of them in the amp)

Is there anything else that I can do short of reverse engineering a schematic and redesigning stuff?
I am handy with a soldering iron and multimeter but haven't worked on amps before. Also, I don't want to spend too much.


3. There are some small silver coloured caps on the input/driver boards that look like they may be electrolytics but I am not sure. Are these electrolytic caps? And would there be worth replacing? You can see these in the photos I've attached.


4. I am under the assumption that it wouldn't be a good idea to replace the main PSU filter caps if the amp seems to be working OK. (They're big, and there's four of them ($$$).) Am I correct in thinking this or would replacing them have a good impact on sound quality?


Thanks in advance!

Items have been removed

Hi,

First of all I'd like to wish you all a happy new year! To start the new year properly I want to build a good DAC.

I want to use the AK4493 DAC. The reference voltage source I have found to be quite high spec'd is the LTC6655 from Linear technology. The problem I have come across is that the AK4493 requires a really high value capacitor (470uF minimum, value dependant on quality of power supply). The LTC6655(5V version) should not be used with capacitive loads larger than 100uF. At 100uF there already is a noise peak, the ideal capacitor should be around 10uF.

My question now is, how do I optimize the VREF capacitor? Should I just go for the 10uF and put the LTC6655 as close as possible?

Thanks in advance!

- Hidde

I am looking for 2 Qty of each of the following:

2 qty SEAS W22NY EXCEL 8" Woofer
2 qty SEAS CA22RNY 8" Woofer
2 qty SEAS 27TBCD DXT Tweeter

I have a US Mailing Address (Port Huron Mi 48060) and I will pay via PayPal.

Hello. I've tried to know how to change the laser diodes in the CDs laser pickup and today finally I've changed a diode in a KSS-272A successfully.

As in other thread about the KSS-190A I said, I tried to change the diode laser and to adjust it, but it don't work. It works in KSS-121A and BU-1C, but no in KSS-272A.

For to adjust the KSS-272A, and others I suppose, you have to adjust the position of the Photodiode array IC. This is main trick.

This is the process.

1) Remove the diode, remove all the glue, clean it, blow with air under pressure.
2) Then place the new diode, type M (both diodes with common cathode), I put a Rohm RLD-78MA. Put glue, I used glue of two components. Wait until the glue is dry.
3) I change all potentiometers. Original are right, but are very hard for to manipulate. All are 2k2.
4) In the photodiode array Ic, remove the glue
5) Place the laser pickup in the mirror, with the 2mm pcb with a hole for the light to the laser.
As I said in the other thread, you force the laser ouput, extend the laser cable and cut the focus conection. In focus conection you conect a power supply(no more than 1 volt) and a low frequency generator.
6) Conect the A-B-C-D-E-F to a signal amplificator, six amplifiers in fact, and conect it to the oscilloscopes.
7) Place a piece of plastic in the fotodiode array with soft glue. It is used for to grab the fotodiode array with care.
8) Conect all, power up the CD, and find the signal. The first signal in appearing are the E-F signals. They are very usefully for to find the signal. In my case the power supply is 700mvdc and the signal generator between 21 or 23hz and between -4dbm or 0dbm.
9) Then you try to find the point like in the pictures appears, where A and C and B and D must be in phase, but 180º disphased between AB and CD. You must build a device like mine with a screew for to lock wheh yo have the right signal.
10) The signal is right and the screw lock the photodiode array for it can't be moved. Now you put glue where you retired the original factory blue. Wait until the glue is dry.
11) Now, without the screw lock the photodiode, you must confirm the signal is right.
12) Install the laser pickup and and ajust power laser and focus. And yes, it's difficult, for this in the point 3 I changed the potentiometers.

The laser power at the output for 1,5Vpp are 204uW.

There's only one problem, in my case the focus potentiometer is all at the left, the signal is clean but I think it could be more clean. I think it's due the RLD-78MA diode is different than the original, and the tolerance is at the limit.

I hope do the experiment again with other diodes that I've purchase and are on way. I want to do the experiment with a KSS-151A too.
I don't have any KSS-190A, but the process must be equal like KSS-151A.

Some pictures. I know, I'm not a great photographer, and the workshop is mess but, what workshop isn't?

KSS-272A June 2020 - Google Photos

Regards

Hello everyone,

Currently our church's activity center PA system consists of arrays of 3 JBL VRX928LAs on each LR and stereo Martin Audio subs all controlled by DriveRack PA2. The PA2 works well for our needs, but we're thinking of relegating it to 2nd duty on a mobile PA rack running Bose F1s and couple SA subs and upgrade the DSP for the main system. We're debating between BBS FDS366T, Ashly Protea 3.6SP or miniDSP DDRC-88A all on the used market (trying to save the church some $$). What are your thoughts on which we should go with? What are the pros and cons? I've done some initial research on these, but would appreciate your advice and first-hand experiences with these units. Also tips on best places to find them would help too. I'm mainly looking at ebay and Reverb. I saw that a diyAudio member here may have a DDRC-88A on sale, but since I'm new, I'm blocked from contacting him atm.

TiA

I've had a few speakers kicking about and found a nice box that they fit in. I've also found a couple of D class amps that can power the 2x3.5" speakers (140w) and the 6" sub (250w). The only problem is when running through a port calculator I'm getting a port length of 442.4cm @35hz which isn't gonna fit in the box! I'm not sure if I've messed up on my calculation and should have used a larger box. Can anyone advise if it's worth carrying on with the project either with a short port or as a sealed sub? I'm trying to build a system to run off of 12v for days out during the summer.

The box is 22x20x24.5cm and was thinking of sealing off the 2x3.5" speakers so would loose a bit more space.

Apologies if newbie questions it's my first build and struggling to get my head around it. 🤔

How do you reckon these two compare? I value clarity and neutrality. What one would you go for?

Ok, this is some older stuff. BUT, you can still upgrade SoundEasy to the current version (US$ 290 at PartsExpress). USB dongle included.

$100 incl. shipping from Europe.

I have bought some used transformers and chokes. Hammond 1650E, and some 193J and 193C chokes. Have built a Tubelab El 84 PP clone and am very happy with the sound. This uses the same output transformers that I have now bought. I want to build an amplifier where I can use the parts I have bought. Thought a push-pull with 6v6? Does anyone have any good advice regarding forms? I build with point to point soldering. Haven't bought a power transformer yet, but that will be done very soon. I have built a few EL 84 PP amplifiers over the years, but was not really satisfied until Tubelab's EL 84 PP was built. Have a lovely winter day! Yesterday it was minus 15 degrees Celsius here, maybe a little warmer outside today?

I’ve recently bought a number of Epcos/TDK DC-link caps. They are a fairly recent developement and look quite different from other DC-links i've seen in that they are cylindrical and much larger than your usual DC-link. They are also somewhat cheaper. The colour is blue. One of the electrodes has four pins around the circumference and the other electrode is in the middle. The datasheet gives no clue on how they should be connected. I’ll be using them in tube amp power supplies and I wonder if anybody has any idea what is best. Should one or four of the outside electrodes be connected to positive, or should the middle electrode be connected to +?

These days I only use DC-links in power supplies and I retrofit DC-links in existing amps. All DC-links are bypassed with GTO caps. This is an explosive combination. You try it or you don’t know what you’re missing.

Have an Adam P22A woofer which makes a harsh clicking sound when being driven hard, but sounds fine below a certain threshold. No visible damage to the cone, makes the same sound when i put it into the other active cabinet so its not the amp either. What could be going on?

I received 3 pairs of AD1862 from Chip1stop . I will keep 1 pair for me and i am selling 2 pairs .
Asking for 80€ per pair (2xAD1862) .
Registered shipping with tracking included in price .
PM me if interested .
Thanks

Hi all,
I exchange a pair of CSample's PCBs for DIY version of FW F1 (for a stereo set) with F2 PCBs.
EU in preference. Thanks.

All the major vendors have listed lm3886 as nonstocked and their prices have almost doubled. Yet nothing like that indicated on the texas instrument page.

Anybody have details on whats going on?

Dear Everyone,

Some of you are probably familiar with the works of AMB Labs. One of their project is called the M3 headphone amp which is a 3 channel hybrid opamp-MOSFET based headphone amp. It is a pretty decent amplifier which I have been using for 15years now. I decided to build a fully differential DAC which could directly drive a fully diff headphone amp (https://www.amb.org/forum/my-gamma3-build-with-a-built-in-fully-balanced-m3-amp-t4735.html) without issues with volume control and the low input impedance of the fully diff headphone amp. This is where my struggle began.
I found a design where a user on head-fi designed a fully diff amp based on the M3. He called it the M4: M4 head-fi link I decided that I wanted to put this into my Gamma 3 DAC until I get an AMB B22 or something similar done (there nothing similar I know, but I have something in mind).
I designed and built the module but I cannot figure out what is wrong with it. I get stuck at the very first initial setup step where the opamp bias current needs to be adjusted. On one side of the differential amp, the one which has the positive input, everything seems fine. On the other side, the R5 resistor (R3 in my design) is stuck at 2.5V = 25mA no matter what I do. The trimpot U$2_1k has no effect on the voltage. If I remove the R3 resistor, the trimpot adjust the voltage on the JFET current source's leg (although it's not a current source at that time). When I removed the MOSFET stage from the amp, I got the same symptoms. I tried to bias the JFET current source (CW pin of U$2 trimpot) to the positive PSU_OPA (V+) instead of the negative, same result. When I removed the Q2 MOSFET bias transistor, the currents were the same and were correctly showing 0.5ish voltage on both R5 resistors (R3 and R10 in my design).

Could someone take a look at my circuit and the PCB design if some error is screaming at you instantly?

I already found the following issues, but resolving them didn't resolve the issue with the CSS or the fact that I couldn't force any current on the MOSFET:

• MOSFETs are mirrored
• Capacitance multiplier is wired wront at the JFET
• VOCM on the OPAMP shouldn't be connected to GND

One solution I was thinking about is to remove the two constant current sources because the JFETs have high tolerance with the Idss and probably ruins the symmetry but I don't know what would happen to the OPAMPs behavior if it was not biased to class A (AMB is saying that is the CSS for but I have never seen any other design having this feature).

Please don't bash on me for not knowing what I am doing. I already know that 😀 although I am trying to get up to speed with the fully diff opamp behavior and basic principles.







This is how the module looks like IRL (the PSU doesn't have a GND wire to avoid the ground loop, would come from the same GND as the balanced input):

I would appreciate if someone could help me out. Also, after we find the error(s), if you are interested, I could send you a pair of PCBs for free so someone else could build this, as well.

My first set of floor standing speakers. Ignore the guinea pig cage, it is time for its cleaning. Using a pair of Tang Band W5-1611SAF 5" Full Range Speaker each. Hindsight being 20-20 I know I made some design errors but it doesn't seem to have affected the sound any. Cut out for the speakers was much better using circle jig and razor to cut the veneer. What do you all think about the way they look. Total of 16 ohms each. Random question, is there anyway to re balance the speakers to 8 ohms using resistors? Either way I'm happy with what I've made so far.

I am planning to build one of the preamp/headphone amps from the diy store.
Was wondering if these linear pots would work as volume control or I really need a log pot?
These are 5K pots, and I have 6 of them. Not sure what else these are usefull for.h

Hi all, Does anyone here have the schematics / service manual covering SA3/S300 amps?

I am working on an hybrid amp
iTube Fatman carbon edition, without an output signal. After sometime of troubleshooting I found one part that was burned labeled U6 on the board near the TDA7265 amp chip and with a smd code A1xx encircled in red in my photo. Can anyone Identify this part since it was burned I can only see A1 but some letters after it are not visible. Since the label is U6 on the board I believed this not a transistor.

Hello all
I am personally sick of the increment system on home sized table saws. I wish they had an indent every mm so that every time I set 10mm I get 10mm, not try to point a dull needle to a wide 1mm mark!

A saw where you can set the fence electronically would be perfect. A small brushless circular saw would make the perfect donor, together with an electronically adjustable fence on a pair of threaded rods. Similar to 3d printer head height mechanism

A good system like this would be faster for panel cutting than CNC, especially for prototyping. I am making a non-electronic system using indentations every mm. Would be awesome if there is collaboration to turn this electronic

A newby here hoping to see if I am on the right track with this schematic and advice. Firstly everything to the left of the JFET came from the LT3080 datasheet application notes. The LT3080 is unique in that it can regulate down to zero volts instead of the usual 1.25, thats why I want to use it. I need a simple variable regulator board that can output from 0 to 35 volts, the 0 to 3 volt range will be used most often in fact so an LM317 wouldn't work here.

This circuit will be for biasing tube grids experimentally, so there will be no current draw when its used, bias on a tube grid just creates a negative field no current draw. This presents a problem, the LT3080 wont work unless it has a minimum load of 1mA. So I thought I would add a constant current sinking shunt at the output, as simple as I can.

So, I want to ensure that 2mA of current is being drawn at any output voltage setting. I want the simplest possible current sink to do this, I think a JFET with a resistor is simplest correct?

If I am on the right track here what would be a good JFET device number to use? I suspect the resistor will be somewhere in the 100 to 200 ohm range depending on the JFET used correct?

Thanks for any help on how I can sink the output of this supply to a constant 2mA so the LT3080 regulates, even in use it wont be drawing any more than that unless I have a gassy tube.

(I corrected the original schematic in post #6)

I received an NAD M3 in a small pile of broken gear. It is in mint condition otherwise, it powers up, but won’t come out if it’s protection mode. It isn’t very old, but seeing the four main filters all bulging I had an idea of what was wrong.

I disassembled it and am currently working on the two amplifier boards. Nearly every capacitor on the board has very high ESR, like a 330uF 16v with and ESR of 27 ohms. Not sure why they choose to use garbage caps, but I find more bad caps in NAD gear than anything else lol. Other than that it seems to be a really, really nice dual mono design.

I was thinking that while I had it apart that maybe I should do some modifications to it, see if I might be able to get some audible improvement.

First: transistors, it uses decent signal transistors throughout the board, mostly being 2SC2240, 2SA970 and 2SC1815, 2SA1015. It also has a pair of 2SA1360 and a pair of 2SC3423. For drivers it uses 2SC4793 and 2SA1837, which I’ve read are actually pretty decent and make good drivers for the outputs I’m thinking of swapping to.

So it originally came with 4 2SC5200 and 4 2SA1943 in each channel. When asking about a transistor sub I learned that while this pair is okay (would have been a downgrade from what I wanted to sub), that a far superior pair would be the MJL3281 and MJL1302. I have several of each from Onsemi/Fairchild. Would this be a worthwhile improvement? Would there be an audible change noticed? Or would I just be wasting money and parts?

Next would be the opamp on each board. Currently uses TL082CP and thinking of an upgrade to maybe a an OPA device like 2134, maybe a 5532, maybe if I’ve had a few too many to drink order the Muses02??? I’d love to hear some suggestions as to what people think would be the best replacement in the $20 or under per device would be. Unless you think of something that is worth more than it’s cost like a Muses02 or a Burson Audio. I wouldn’t mind trying one of these exotic as long as people think it’s worth it.

I think I’ll keep it at there before this post gets too long and add to it as I make progress on the amp.

So first what are thought about upgrading the 2SC5200/2SA1943 to the MJL3281/MJL1302 and while we’re at it if anyone recommends upgrading the drivers or any of the 1815/1015 with lower noise devices. Have plenty KSA1220/KSC2690 and KSA1381/KSC3503, and more. Haven’t peeled at the spec sheet to see what would be a good drop in from the originals, and neither may perform as well as the originals. Just asking though.

Next would be the upgrade to the stock opamp. Would love to hear some suggestions.

For the capacitors I’m using Panasonic FC and Elna Silmic II (or I have Nichicon FG, I have Muse too, but they’re physically too big). Oh which brings me to the film caps. They’re small and grey, unsure of brand or film type. Was thinking of swapping them all out with Wima polypropylene.




Unsure about resistors. They use your standard metal film. Any benefit to upgrading them as well? Basically looking for improvements that can be heard.

Thank you much!
Dan

Greetings !! I am new here and hoping someone could help. I am in need of a schematic for a Monster MPA 3250. Any help, please? Thank you !!

I have a Paradigm Seismic 110 with a broken rear switch, someone else had removed it and soldered on 3 cables leading to a connector box. I'm presuming this was to bypass a broken 3 pin 3 way switch as you can see in the picture. I can't seem to find the right kind of switch, would it come up as a different name for home AV parts?

Any help would be excellent and, on this what someone has done with this connector, would I just join one piece of cable to the left or right and then tough the centre with the other end to activate it?

I have a Ct sounds 2k amplifier. I am trying to sort out issues in the power supply. The ps mosfets are shorted, a few gate resistors are out of spec and it appears that half of these small transistors are burned. I am having an issue identifying the transistors, I can see L6 stamped on a few of them, I think they are 2sc1623L6TP. Can anyone confirm? Also I can’t confirm the part #’s on the burned ones, any thoughts on how to figure those out?

Anyone built the Bugle2 ?

I went to hit start on my long standing Scott Thompson modded Technics SL-1600MK2 turntable and the tonearm moved straight across the record and plopped itself down near the spindle.

I caught it quick enough. While holding the headshell lift, i hit "stop". It kept pushing back and clicking. Turned it OFF and it STILL clicked all the way back to the rest.

Tried it with the stylus protector down (Shure V15 MKIII) and a crappy record. It seemed to work again, but it would yelp out a click close to setting the tonearm down on the rest. the arm would momentarily stop moving when clicking.
The auto lift rubber O ring is not even a year old. It was easy enough for me to install myself.

Something tells me it has a cracked gear. like this one:
https://www.ebay.com/itm/323707146252?i ... R8bpnZDrYw

IMPORTANT: Scott has since retired and moved out of state... he did just e-mail me, saying the above gear is not exactly right and would have to be modified a bit to fit. does anyone know of the EXACT replacement gear? should i have one 3D printed?

i know this forum is literally called "do it yourself", but is anyone in the san francisco bay area willing to do the job? i'd pay you, obviously.

Regards,
Robby

Hi for sale are two of Alan Wrights books. Asking $30 for Super Cables book (3rd addition) and Tube Preamp Cook book (2nd addition) asking $45. Or both for $70 plus $7.00 for shipping US only please. Some pages Super Cable book are underlined and Tube Pre Amp book has loose page but all pages are there.

hello to the whole group.
is it possible to use the electronics of a cd player as a DAC?
let me explain: I have an old Philips player that no longer reads CDs so I would like to use its DAC (2xTDA 1540) as a DAC for my system.
2 or 3 selectable inputs (optical and coaxial).
possible or impossible?
Thanks in advance.

I need to replace a failing Sanyo SFP1 6/6 in an Audiomeca Kreatura CD transport.

I cannot find a direct replacement anywhere but some vendors are advertising the SF90 as being cross compatible.

Can anyone here confirm?

Hello All...

I need Black Gate N series 1uf 50V. Please message me if you have one.

Thanks

Avr 5805

Anybody out there who is able to help with a question on the Denon
AVR 5805?
Last weekend the unit suddenly stopped output to the speakers.
The part of the movie being watched was not even overly loud.
For several reasons i can not afford right now to bring the unit to
a repair center, plus every time it ends up costing about $ 600.00 .
So i got the repair manual and started to check it out.
I found that the main transformer (which runs the output amps) did not get any power. The power to it is controlled by a relay. The logic circuit controlling the relay have several inputs. Two of these signals are called "POWER" and the second one is called "AC_P.DOWN". The later seems to be used to shut things down.
Does anybody know under what circumstances that signal will be send out?

Thanks Gernot javascript:smilie('😀')

For sale 2 pieces of SiderealKaps Premium Audio Grade Capacitors. 5.0 microfarad +/- 10% 200 V.
Used but fully functional (burnt-in 😉).
15 EUR + postage. EU buyer preferred due to customs.

I have a diy store universal power supply that I built for my aleph j. It was the first thing I built for this diy hobby. I haven’t had any issues with it, I just wanted to try something else. I would love it to go to another diy’er. No strings attached, no guarantees, US shipping only, totally free.

Im on search for a pair or 4 pieces empty or completed boards of chipamp aka gainclone with Lm3875 or Lm3886.Maybe some boards from Brian GT(chipamp.com) or some other good boards maybe some Neurocrome Lm3886 (doit right)......
If you have some for sale plese contact me.😉

I want to start by saying thanks for those who responded.

I’m attempting to build my first speaker setup. I have chose the TDA7850 IC due to its simplicity and have concerns about multiple audios sources.

I’m planning on adding a Bluetooth module, 3.5mm jack, and an iPod connector since I have it lying around.

My question is how do I handle the different audio voltages. For instance if I feed the 3.5mm input and have the volume set at a particular level, when connecting Bluetooth wouldn’t the volume level change if it has lower or higher input voltages?

How would I handle this? I’ve stumbled across Automatic Gain Control so would this be a viable option? Or does anyone else have a recommendation?

Hi,
I received a powered subwoofer for service.
It has an opamp input stage followed by collector output.
Kindly help me get the schematic.

This amplifier was damaged by shorted output leads.
Kindly help

Hello all...

I would like to make this project, but I don't know what to use as a bluetooth module with APTX LL

I have to have:
Blue socket - Black 3.5 mm jack cable (used to operate remote controls)
White RCA jack - White RCA cable
Red RCA jack - Red RCA cable
Black 3.5 mm jack - AUX port ( will turn everything else off)
Pink 3.5 mm jack - Microphone
Black DC jack - Black 12V DC power cord

a few questions, wanting to proceed using the BK8000L, I don't know where to connect the two wires from the blue socket for the steering wheel remote controls
it is appreciated to be able to program the bluetooth name how to do it?
Thanks

Translated with DeepL.com (free version)

Just found, maybe of interest:
Vorverstärker mit diskretem OpAmp und komplementärer Differenz-Eingangsstufe

A long time ago I purchased an MC cartridge from a seller on ebay - I forgot all about it until recently and then found it hidden away somewhere - I fitted it to my Pro-ject turntable (needed additional weight - I don't think that is optimal so further work to be done).

I can't find anything in my e-Bay purchase history and there aren't any identifying marks on the cartridge itself so I was hopeful that someone could chime in and tell me what it is.

Hi guys,
I am going to start a new project a subminiature Fender Champ clone, but with tone control (more similar with the 5F2).
Regarding the valves, the 12AX7 will be replaced by a 6N21B and the 6V6GT by a 6P30B-R. I like to use a pot on the cathode of the valve, so I can change the bias of the first stage. With the bypass cap, I won't loose signal level when I mess with the pot.

I've done a first schematic. Please tell me what do you think?

Cheers,
Pedro

Hi, I have a Velodyne Impact 12BG sub with a rattling cabinet. I'd like to make a folded horn cabinet for the driver and amp and was wondering if anyone has a starting point I can use?

I am not a designer, but am very good with wood working and minor electronics

Thanks in advance,

Why no such comparisons here? Too anxious about the results 🙂

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Around 05:00 is a nice mid-tempo sequence for testing!

Greetz - The ReSultanz of Zound

Still unbeaten til today :

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I ve googled around a bit, but did not find e.g. the monkey from Th.Loesch in PP anymore as the lnks are down...basically a DRD, but in PP. But besides this, any direct-coupled version would be interesting to compare...especially if you can comment the sound as you have build it !

Thx a lot

Is there a way to use a touchscreen monitor with Daphile without using another computer? I'm trying to build a music player (not server) and would like a all in one solution.
I might not have explained my question well enough. Nothing is wrong with the computer I have Daphile installed on. Daphile uses a web interface to control it. I want to use my touchscreen monitor to control it.

John

Hi all, been off the forum for awhile but slowly getting back into DIY, something that will enable that, is getting my main "family" friendly, commercial system to the point where I am mainly happy 🙂.

Looking to finish it with something for sale on Subito, but I have sofar been unsuccessful in getting an account. If someone has an account could you please pass on my contact details? Please pm me if able. Cheers.

I built a few different Pearl 3’s and wanted to try one with a VRDN in the same chassis with Wall Wart instead of the transformer and I was very happy with the result and built one the same way for a friend. This is a spare one I do not need.

Galaxy 1 U chassis
VRDN PSU set to 18V
16 Volt AC-AC Triad Wall Wart (with added ferrites)
Opa 1656 dual opamps
Closely matched resistors and Caps on both Pearl boards.
Xlr and SE outputs

Asking $425 with free ship anywhere in the continental US.

FS Twisted pair Audio Metronome ASRC new in box

Again from Job lot, don't know what it's for but here's the link to the products webpage


http://www.twistedpearaudio.com/digital/metronome.aspx


£25 plus shipping at cost anywhere

I'm redesigning my system starting with speakers. I have just purchased a set of black Rogers LS5/9 stand mount speakers which will be on 600mm custom stands. I know having these on high stands will effect the lower frequency. I'm thinking they will roll off around 80Hz. The plan is to build two passive enclosures running a set of classic AD12100W8 12 inch Philips drivers per box, one each channel that will be placed horizontal behind the Rogers against the wall that will cross from around 120Hz but run the Rogers at their full frequency response. I want to achieve these to go down to around 30Hz. The room has terrible bass response reason why I want to go this way.

Has anyone gone in this root?

I have 1,5 of these boards. And yes, the LM394 is intact. And lots of other components.

$150 + shipping at cost.

R

Hello there,
I have noticed the ever increasing use of 'simulation software', with both success and problems.
I would like to hear peoples thoughts & opinions.
EG. Are cheap USB microphones really up to task?